owners manual/ maintenance manual digit™ fm exciter 994 9410

owners manual/ maintenance manual digit™ fm exciter 994 9410
OWNERS MANUAL/
MAINTENANCE MANUAL
DIGIT™ FM EXCITER
994 9410 001
988-2333-001
T.M. No. 888-2333-001
Printed: December 14, 1994
© Copyright 1993, 1994, 1995
Rev. F: 10-09-96
Harris Corporation
All rights reserved
Returns And Exchanges
Damaged or undamaged equipment should not be returned unless written approval and a
Return Authorization is received from HARRIS CORPORATION, Broadcast Systems Division. Special shipping instructions and coding will be provided to assure proper handling.
Complete details regarding circumstances and reasons for return are to be included in the
request for return. Custom equipment or special order equipment is not returnable. In those
instances where return or exchange of equipment is at the request of the customer, or
convenience of the customer, a restocking fee will be charged. All returns will be sent
freight prepaid and properly insured by the customer. When communicating with HARRIS
CORPORATION, Broadcast Systems Division, specify the HARRIS Order Number or Invoice Number.
Unpacking
Carefully unpack the equipment and preform a visual inspection to determine that no apparent damage was incurred during shipment. Retain the shipping materials until it has been
determined that all received equipment is not damaged. Locate and retain all PACKING
CHECK LISTs. Use the PACKING CHECK LIST to help locate and identify any components
or assemblies which are removed for shipping and must be reinstalled. Also remove any
shipping supports, straps, and packing materials prior to initial turn on.
Technical Assistance
HARRIS Technical and Troubleshooting assistance is available from HARRIS Field Service
during normal business hours (8:00 AM - 5:00 PM Central Time). Emergency service is
available 24 hours a day. Telephone 217/222-8200 to contact the Field Service Department
or address correspondence to Field Service Department, HARRIS CORPORATION, Broadcast Systems Division, P.O. Box 4290, Quincy, Illinois 62305-4290, USA. Technical Support
by e-mail: [email protected] The HARRIS factory may also be contacted through a FAX
facility (217/221-7096).
Replaceable Parts Service
Replacement parts are available 24 hours a day, seven days a week from the HARRIS
Service Parts Department. Telephone 217/222-8200 to contact the service parts department
or address correspondence to Service Parts Department, HARRIS CORPORATION, Broadcast Systems Division, P.O. Box 4290, Quincy, Illinois 62305-4290, USA. The HARRIS factory may also be contacted through a FAX facility (217/221-7096).
NOTE
The # symbol used in the parts list means used with (e.g. #C001 = used with C001).
MANUAL REVISION HISTORY
DIGIT™
888-2333-XXX
Rev.
ECN
Date
Pages Changed
001-A
TBD
03-17-95
Title Page and page 2-4
Added MRH-1/MRH-2
001-B
39911
05-08-95
Title Page, MRH-1/MRH-2 and pages 7-1 & 7-2
001-C
39900
05-09-95
Title Page, MRH-1/MRH-2 and pages 7-4 to 7-6
001-D
39948
06-23-95
Title Page, MRH-1/MRH-2 and pages 7-4 to 7-6
001-E
40104
09-19-95
Title Page, MRH-1/MRH-2 and pages 7-4 to 7-6
001-F
41546
10-09-96
Title Page, MRH-1/MRH-2 and page 2-3
MRH-1/MRH-2
WARNING
THE CURRENTS AND VOLTAGES IN THIS EQUIPMENT ARE DANGEROUS. PERSONNEL MUST AT ALL TIMES OBSERVE SAFETY WARNINGS, INSTRUCTIONS
AND REGULATIONS.
This manual is intended as a general guide for trained and qualified personnel who are aware of the dangers inherent in
handling potentially hazardous electrical/electronic circuits. It is not intended to contain a complete statement of all safety
precautions which should be observed by personnel in using this or other electronic equipment.
The installation, operation, maintenance and service of this equipment involves risks both to personnel and equipment, and
must be performed only by qualified personnel exercising due care. HARRIS CORPORATION shall not be responsible for
injury or damage resulting from improper procedures or from the use of improperly trained or inexperienced personnel
performing such tasks.
During installation and operation of this equipment, local building codes and fire protection standards must be observed.
The following National Fire Protection Association (NFPA) standards are recommended as reference:
- Automatic Fire Detectors, No. 72E
- Installation, Maintenance, and Use of Portable Fire Extinguishers, No. 10
- Halogenated Fire Extinguishing Agent Systems, No. 12A
WARNING
ALWAYS DISCONNECT POWER BEFORE OPENING COVERS, DOORS, ENCLOSURES, GATES, PANELS OR SHIELDS. ALWAYS USE GROUNDING STICKS AND
SHORT OUT HIGH VOLTAGE POINTS BEFORE SERVICING. NEVER MAKE INTERNAL ADJUSTMENTS, PERFORM MAINTENANCE OR SERVICE WHEN ALONE
OR WHEN FATIGUED.
Do not remove, short-circuit or tamper with interlock switches on access covers, doors, enclosures, gates, panels or shields.
Keep away from live circuits, know your equipment and don’t take chances.
WARNING
IN CASE OF EMERGENCY ENSURE THAT POWER HAS BEEN DISCONNECTED.
WARNING
IF OIL FILLED OR ELECTROLYTIC CAPACITORS ARE UTILIZED IN YOUR
EQUIPMENT, AND IF A LEAK OR BULGE IS APPARENT ON THE CAPACITOR
CASE WHEN THE UNIT IS OPENED FOR SERVICE OR MAINTENANCE, ALLOW
THE UNIT TO COOL DOWN BEFORE ATTEMPTING TO REMOVE THE DEFECTIVE CAPACITOR. DO NOT ATTEMPT TO SERVICE A DEFECTIVE CAPACITOR
WHILE IT IS HOT DUE TO THE POSSIBILITY OF A CASE RUPTURE AND SUBSEQUENT INJURY.
i
ii
FIRST-AID
Personnel engaged in the installation, operation, maintenance or servicing of this equipment are urged to become familiar
with first-aid theory and practices. The following information is not intended to be complete first-aid procedures, it is a
brief and is only to be used as a reference. It is the duty of all personnel using the equipment to be prepared to give
adequate Emergency First Aid and thereby prevent avoidable loss of life.
Treatment of Electrical Burns
1.
Extensive burned and broken skin
a.
Cover area with clean sheet or cloth. (Cleanest available cloth article.)
b.
Do not break blisters, remove tissue, remove adhered particles of clothing, or apply any salve or ointment.
c.
Treat victim for shock as required.
d.
Arrange transportation to a hospital as quickly as possible.
e.
If arms or legs are affected keep them elevated.
NOTE
If medical help will not be available within an hour and the victim is
conscious and not vomiting, give him a weak solution of salt and soda:
1 level teaspoonful of salt and 1/2 level teaspoonful of baking soda to
each quart of water (neither hot or cold). Allow victim to sip slowly
about 4 ounces (a half of glass) over a period of 15 minutes. Discontinue fluid if vomiting occurs. (Do not give alcohol.)
2.
Less severe burns - (1st & 2nd degree)
a.
Apply cool (not ice cold) compresses using the cleanest available cloth article.
b.
Do not break blisters, remove tissue, remove adhered particles of clothing, or apply salve or ointment.
c.
Apply clean dry dressing if necessary.
d.
Treat victim for shock as required.
e.
Arrange transportation to a hospital as quickly as possible.
f.
If arms or legs are affected keep them elevated.
REFERENCE:
ILLINOIS HEART ASSOCIATION
AMERICAN RED CROSS STANDARD FIRST AID AND PERSONAL SAFETY MANUAL (SECOND EDITION)
iii
Table of Contents
Section I
General Description
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Equipment Purpose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Input Interface Modules . . . . . . . . . . . . . . . . . . . . . . . . . .
The Digital Stereo Generator Module . . . . . . . . . . .
The Analog I/O Module . . . . . . . . . . . . . . . . . . . . . .
Available Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Physical Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Input Options. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Digital Modulation Process . . . . . . . . . . . . . . . . . . . . . . .
Frequency Selection . . . . . . . . . . . . . . . . . . . . . . . . .
N+1, Frequency Agile Configuration . . . . . . . . . . . .
Controls and Indicators. . . . . . . . . . . . . . . . . . . . . . . . . . .
Explanation of Terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Performance Specifications . . . . . . . . . . . . . . . . . . . . . . . . .
Section II
Installation
Unpacking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Removal of VCO Shipping Screws . . . . . . . . . . . . . . . . .
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Physical Mounting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Cooling Airflow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Digital Stereo Generator Module (A5) . . . . . . . . . . . . . .
Program, SCA and RBDS Inputs . . . . . . . . . . . . . . .
Digital Audio Input Connector, J9 . . . . . . . . . . . . . .
I/O and Remote Control, J7 . . . . . . . . . . . . . . . . . . .
Pre-emphasis Selection . . . . . . . . . . . . . . . . . . . . . . .
Digital Stereo Generator Module Alignment Procedure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Select Operational Mode (Dip Switch settings) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Mono Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Analog Backup Mode . . . . . . . . . . . . . . . . . . . . .
Pre-Emphasis and Permanent Mode Selection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Setting SCA and Pilot levels . . . . . . . . . . . . . . . . . .
Setting the Output Deviation and Limiting
Level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Analog I/O Module (A5) . . . . . . . . . . . . . . . . . . . . . . . . .
Program and SCA inputs . . . . . . . . . . . . . . . . . . . . .
Input Specifications . . . . . . . . . . . . . . . . . . . . . . . . . .
Pre-emphasis Jumper. . . . . . . . . . . . . . . . . . . . . . . . .
Input Cables. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Setting Modulation Level . . . . . . . . . . . . . . . . . . . . .
Setting Monaural Level . . . . . . . . . . . . . . . . . . . .
Exciter RF Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Remote Metering and Control, J2 . . . . . . . . . . . . . . . . . .
Remote Frequency Select, J3 (Optional) . . . . . . . . . . . . .
1-1
1-1
1-1
1-1
1-1
1-1
1-1
1-2
1-2
1-2
1-2
1-2
1-2
1-2
1-2
2-1
2-1
2-1
2-1
2-1
2-1
2-1
2-2
2-2
2-2
2-2
2-3
2-3
2-3
2-3
2-3
2-4
2-4
2-4
2-5
2-5
2-5
2-5
2-5
2-5
2-6
2-6
2-6
2-7
Section III
Operation
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
Fault Indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
Modulation Level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
iv
Metering and Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Display Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DC Power Indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Emergency Operating Procedure . . . . . . . . . . . . . . . . . . . .
Switching to the Analog Backup Mode . . . . . . . . . . . . .
Section IV
Theory of Operation
General Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Block Diagram Description. . . . . . . . . . . . . . . . . . . . . . . . .
Input Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Digital Stereo Generator Module (A5) . . . . . . . . . .
Analog I/O Module (A5) . . . . . . . . . . . . . . . . . . . . .
Digital Modulator Board (A3) . . . . . . . . . . . . . . . . . . . .
5 MHz Filter Board (A8) . . . . . . . . . . . . . . . . . . . . . . . .
PLL Board (A7). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
VCO Module (A6). . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Upconverter Board (A4) . . . . . . . . . . . . . . . . . . . . . . . . .
100 MHz Filter Board (A9) . . . . . . . . . . . . . . . . . . . . . .
55 Watt PA Module (A1) . . . . . . . . . . . . . . . . . . . . . . . .
Regulator Board (A2) . . . . . . . . . . . . . . . . . . . . . . . . . . .
Remote Frequency Tuning Input, J3 (Optional) . . . . . .
Remote Control and Status, J2 . . . . . . . . . . . . . . . . . . .
Exciter PA Status (FWD PWR, RFL PWR,
PAV, PAI). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Exciter Fault and No Program Status (Fault,
NoPgm) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Exciter Mute (Mute) . . . . . . . . . . . . . . . . . . . . . . . .
Automatic Power Control (APC) . . . . . . . . . . . . . .
Automatic Fault Control Interlock (AFC
Com, AFC NC, AFC NO) . . . . . . . . . . . . . . . . . .
RF Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AC Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Regulated Power Supplies. . . . . . . . . . . . . . . . . . . . . . . .
Detailed Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Front Panel Interface . . . . . . . . . . . . . . . . . . . . . . . . . . .
Front Panel Controls . . . . . . . . . . . . . . . . . . . . . . . .
Power Supply indicators . . . . . . . . . . . . . . . . . . . . .
Modulation level . . . . . . . . . . . . . . . . . . . . . . . . . . .
Digital Stereo Generator Module, A5. . . . . . . . . . . . . . .
Data Rate Conversion . . . . . . . . . . . . . . . . . . . . . . .
Analog SCA and RBDS Injection. . . . . . . . . . . . . .
Composite Compression . . . . . . . . . . . . . . . . . . . . .
Analog Backup Mode . . . . . . . . . . . . . . . . . . . . . . .
Operational Mode Control . . . . . . . . . . . . . . . . . . . .
LED Meter . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ANALOG (Switch). . . . . . . . . . . . . . . . . . . . . . .
MONO (Switch) . . . . . . . . . . . . . . . . . . . . . . . . .
25uS, 50uS (Switches) . . . . . . . . . . . . . . . . . . . .
ERR (Switch) . . . . . . . . . . . . . . . . . . . . . . . . . . .
WATCHDOG (Switch) . . . . . . . . . . . . . . . . . . .
Digital Stereo Generator Module User Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SCA (Pot Adjustment) . . . . . . . . . . . . . . . . . . . .
DEV (Pot Adjustment) . . . . . . . . . . . . . . . . . . . .
PILOT (Pot Adjustment) . . . . . . . . . . . . . . . . . .
EQ (Pot Adjustment) . . . . . . . . . . . . . . . . . . . . .
888-2333-001
WARNING: Disconnect primary power prior to servicing.
3-1
3-1
3-2
3-2
3-2
3-2
4-1
4-1
4-1
4-1
4-1
4-2
4-2
4-2
4-2
4-2
4-2
4-2
4-2
4-2
4-3
4-3
4-3
4-3
4-3
4-3
4-4
4-4
4-4
4-4
4-4
4-4
4-4
4-4
4-4
4-4
4-4
4-4
4-5
4-5
4-5
4-5
4-6
4-6
4-7
4-7
4-7
4-7
4-7
4-7
4-7
12-14-94
LIMIT (Pot Adjustment). . . . . . . . . . . . . . . . . . . 4-7
Digital Stereo Generator Module Outputs . . . . . . . 4-8
PLL UNLOCK (Output). . . . . . . . . . . . . . . . . . . 4-8
RBDS SYNC (Output) . . . . . . . . . . . . . . . . . . . . 4-8
Analog I/O Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-8
Analog Inputs (J2 through J7) . . . . . . . . . . . . . . . . 4-8
Balanced Composite (J6) . . . . . . . . . . . . . . . . . . 4-8
Unbalanced Composite (J5) . . . . . . . . . . . . . . . . 4-9
SCA1 SCA2 SCA3 (J2, J3, J4). . . . . . . . . . . . . 4-9
Monaural (J7) . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-9
Data Output Connector (J1). . . . . . . . . . . . . . . . . . . 4-9
Digital Modulation Output (M0, M1, ... ,
M15) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-9
Analog I/O Module Power (+17V, -17V,
+6.5V, and -6.5V). . . . . . . . . . . . . . . . . . . . . . . . . . 4-9
Digital Modulator Board . . . . . . . . . . . . . . . . . . . . . . . . . 4-9
Data Input connector (J1) . . . . . . . . . . . . . . . . . . . . 4-9
Interface Module Power (+17V, -17V,
+6.5V, and -6.5V). . . . . . . . . . . . . . . . . . . . . . . . . . 4-9
Remote Frequency Input (J6 Optional) . . . . . . . . . 4-9
Power Input, Serial Data, and Status (J9) . . . . . . . 4-9
Serial Bargraph Interface . . . . . . . . . . . . . . . . . . . . . 4-9
NOPGM Fault . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-10
Remote Frequency Mute Input (N+1 Mute) . . . . 4-10
FM Output (J7) . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-10
DAC Test Output (J8) . . . . . . . . . . . . . . . . . . . . . . 4-10
Adjustments/Settings . . . . . . . . . . . . . . . . . . . . . . 4-10
Functional Settings (S5) . . . . . . . . . . . . . . . . . . 4-10
Frequency Setting Switches (S2, S3, S4) . . . . 4-10
5MHz Filter Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-11
Power Connector (J1) . . . . . . . . . . . . . . . . . . . . . . 4-11
5MHz Fault . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-11
FM Input (J2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-11
FM Output (J3) . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-11
PLL Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-11
Coarse Frequency Setting . . . . . . . . . . . . . . . . . . . 4-12
Power Connector (J6) . . . . . . . . . . . . . . . . . . . . . . 4-12
PLL Loss of Lock . . . . . . . . . . . . . . . . . . . . . . . . . 4-12
N+1 connector (J3 Optional) . . . . . . . . . . . . . . . . . 4-12
VCO Tuning Voltage (J1) . . . . . . . . . . . . . . . . . . . 4-12
VCO Input (J2) . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-12
Notch Output (J4) . . . . . . . . . . . . . . . . . . . . . . . . . 4-12
PLL Board Output (J5) . . . . . . . . . . . . . . . . . . . . . 4-12
+15V Output to VCO (J7) . . . . . . . . . . . . . . . . . . . 4-12
-15V Output to VCO (J8) . . . . . . . . . . . . . . . . . . . 4-12
VCO Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-12
VCO Output (E1). . . . . . . . . . . . . . . . . . . . . . . . . . 4-13
VCO Tuning Input (E2). . . . . . . . . . . . . . . . . . . . . 4-13
VCO Power Supply +15V. -15V (E3, E4) . . . . . . 4-13
Upconverter & 100MHz Filter (A4). . . . . . . . . . . . . . . 4-13
Power Connector (J2) . . . . . . . . . . . . . . . . . . . . . . 4-13
Upconverter Fault . . . . . . . . . . . . . . . . . . . . . . . . . 4-13
Upconverter, J1 . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-13
LO (PLL) Input (J5). . . . . . . . . . . . . . . . . . . . . . . . 4-13
5.6MHz FM Input (J6). . . . . . . . . . . . . . . . . . . . . . 4-14
Upconverter Output (J8) . . . . . . . . . . . . . . . . . . . . 4-14
100MHz Filter Output (J10) . . . . . . . . . . . . . . . . . 4-14
100MHz Filter Board, A9 . . . . . . . . . . . . . . . . . . . . . . . 4-14
100MHz Filter Board Power Connector (J9) . . . . 4-14
100MHz Filter Output (A9J11) . . . . . . . . . . . . . . . 4-14
12-14-94
Regulator Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AC Power Supply Input (J1) . . . . . . . . . . . . . . . . .
B+ Supply Input (J2) . . . . . . . . . . . . . . . . . . . . . . .
Power Amplifier I/O (J3) . . . . . . . . . . . . . . . . . . . .
Forward Power Input (J3-1) . . . . . . . . . . . . . . .
Reflected Power Input (J3-2) . . . . . . . . . . . . . .
PA Temperature Input (J3-4) . . . . . . . . . . . . . .
PA Collector Voltage Input (J3-9) . . . . . . . . . .
PA Base Voltage Output (J3-12) . . . . . . . . . . .
Front Panel Overlay Connector (J8) . . . . . . . . . . .
Remote Output Connector (J9) . . . . . . . . . . . . . . .
Exciter PA Status (FWD PWR, RFL PWR,
PAV, PAI) . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Exciter Fault and No Program Status
(Fault, NoPgm) . . . . . . . . . . . . . . . . . . . . . . . . .
Exciter Mute (Mute) . . . . . . . . . . . . . . . . . . . . .
Automatic Power Control (APC) . . . . . . . . . . .
Automatic Fault Interlock Control (AFC
Com, AFC NC, AFC NO) . . . . . . . . . . . . . . . .
Power Distribution (J4, J5, J6, J7) . . . . . . . . . . . . .
Digital Modulator Board Interface (J4) . . . . . . . . .
No Program input (NoPgm) . . . . . . . . . . . . . . .
Remote Frequency Mute (N+1 Mute) . . . . . . .
PLL Lock Inputs (J5, J6, J7) . . . . . . . . . . . . . . . . .
Regulator Board Adjustments and Settings . . .
4-16
4-16
4-16
4-16
4-16
4-16
4-16
Section V
Maintenance and Alignment
Preventative Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . .
Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Cooling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Periodic Exciter Alignments . . . . . . . . . . . . . . . . . . . . . . . .
Channel Setting and Frequency Adjustment. . . . . . . . . . . .
How Frequency is Selected . . . . . . . . . . . . . . . . . . . . . . .
Digital Modulator Switches . . . . . . . . . . . . . . . . . . . . . . .
PLL Board Switches . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Selecting a Frequency . . . . . . . . . . . . . . . . . . . . . . . . . . .
Frequency Selection Chart . . . . . . . . . . . . . . . . . . . . . . . .
Setting the TCXO. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Test Equipment You Will Need: . . . . . . . . . . . . . . .
Procedure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Exciter Power Level and Power Metering . . . . . . . . . . . . .
Test Equipment Setup . . . . . . . . . . . . . . . . . . . . . . . . . . .
Forward Meter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Forward Remote . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Exciter APC (R6) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Analog I/O Module Adjustments. . . . . . . . . . . . . . . . . . . . .
Input Signal Level Calibration. . . . . . . . . . . . . . . . . . . . .
Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Equipment Required . . . . . . . . . . . . . . . . . . . . . . . . .
Setting Modulation Level . . . . . . . . . . . . . . . . . . . . .
Setting Monaural Level . . . . . . . . . . . . . . . . . . . . . .
Digital Stereo Generator Module Adjustments. . . . . . . . . .
5-1
5-1
5-1
5-1
5-1
5-1
5-1
5-2
5-2
5-2
5-2
5-2
5-2
5-3
5-3
5-3
5-3
5-3
5-3
5-3
5-3
5-3
5-4
5-4
5-4
Section VI
Troubleshooting
Faults. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SWR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
TEMPERATURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
PLL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
PERCENT MODULATION /10 . . . . . . . . . . . . . . . . . . .
6-1
6-1
6-1
6-1
6-1
888-2333-001
WARNING: Disconnect primary power prior to servicing.
4-14
4-14
4-15
4-15
4-15
4-15
4-15
4-15
4-15
4-15
4-15
4-15
4-15
4-16
4-16
v
RF Output Foldback . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fuses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DC Power Indicators. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Remote Indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Remote FAULT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
NOPGM. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Signal Tracing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Approximate RF and IF Frequencies . . . . . . . . . . . . . . . .
Troubleshooting Flow Charts . . . . . . . . . . . . . . . . . . . . . . . .
6-1
6-1
6-1
6-1
6-2
6-2
6-2
6-2
6-2
Section VII
Parts List
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1
ADDITIONAL INFORMATION SUPPLIED AT END OF MANUAL
——————————————————————————————————————————————
-
MAINTAINING A 100% DIGITAL PATH FROM THE STUDIO TO THE “ON AIR” SIGNAL
PRE-EMPHASIS AND FM LIMITING CONSIDERATIONS FOR AUDIO PROCESSORS AND DIGI-
vi
888-2333-001
WARNING: Disconnect primary power prior to servicing.
12-14-94
Section I
General Description
1.1 Introduction
This technical manual contains the information needed to install,
operate and maintain the DIGIT™, Digital FM Exciter. This highlyreliable product will require little adjustment or attention. DIGIT™
is backed by an unprecedented 3 year warranty exchange program.
Exchange or replacement modules are available through Harris-Allied Broadcast Products if any component ever fails.
tional Monaural and/or Composite (balanced or unbalanced)
audio inputs and 3 SCA signals. The unit then converts the
combined inputs into the 16-Bit digital input required by the
DIGIT™ exciter. The assembly is removable allowing the module to be replaced by the Digital Stereo Generator Module,
quickly and easily.
1.2 Equipment Purpose
DIGIT™ is a high-performance FM exciter, utilizing modern digital
component technology and innovative design techniques to produce
an FM signal of exceptional quality and reliability. The DIGIT™,
Digital Exciter inputs a digital composite stereo signal and generates
an on carrier FM signal at power levels up to 55 watts. The FM
modulation process is fully digital and is extremely stable. DIGIT™
is also frequency agile and can be used in N+1 configurations.
DIGIT™ can be supplied in new transmitting equipment or may be
purchased as an upgrade for nearly any FM transmitter. The exciter’s small size, 55 watt output capability and versatile interfacing
make it an ideal choice for installation to replace an older exciter in
most existing FM transmitters.
DIGIT™ is also FCC Type-Notified for use as a low-power or
emergency backup transmitter when it is used with the StandAlone Transmitter Option, Harris Part #994-9506-001. (The
option includes the required Low-Pass Filter).
1.2.1 Input Interface Modules
Either of the following two input modules may be installed at the
exciter input, depending on the type of input signal to be used
1.2.1.1 The Digital Stereo Generator Module
This is considered the standard interface for the exciter. It can also
be used as an upgrade or replacement for the optional Analog I/O
Module. It allows the Harris DIGIT™ exciter to accept a 24 bit
AES/EBU compatible digital stereo audio signal input, along with
two analog SCA inputs and one RBDS (Radio Broadcast Data
Signal) input. It includes a DSP based stereo generator that will
provide the exciter with a “CD” quality digital composite signal. All
stereo encoding functions are implemented in the digital domain.
This gives the broadcaster the advantage of a completely digital link
from the studio source to the transmitter for the first time. The unit
has level adjustments for all inputs as well as user adjustable
composite limiting. The module can also be operated in the analog
backup mode which allows the use of an analog composite audio
input in the case of a loss of the digital audio signal, and the module
can be used in either the stereo or mono mode of operation.
1.2.2 Available Options
• Stand Alone Transmitter Kit - Part #994-9506-001 - This
includes the Harmonic Filter/RF Sample necessary to use
the exciter as a stand alone transmitter.
• Remote Cable Adapter Kit - Part #992-8941-001 - This
includes a prewired 5 ft. cable with D connectors on both
ends and a terminal strip with a D connector on the back.
This kit can be used to facilitate remote interfacing with
non-Harris transmitters.
• Remote Frequency Control Kit - Part #994-9478-001 - For
N+1 applications only.
There are also various Spare Parts Kits and Mounting Kits available as
shown on the Digital FM Exciter Family Tree, DWG #843-5295-022.
1.3 Physical Description
DIGIT™ is supplied in a fully-enclosed case, which may be used
as a free-standing enclosure or mounted in a standard 19 inch rack,
7 inches (4 Rack Units) high, see Figure 1-1. A rack mount kit
assembly is included with the exciter. Optional rack mount kits are
also available to allow installation of DIGIT™ into existing Harris
HT or PT Series FM transmitters. A complete listing of the available
rack mount kits, and Harris part numbers, can be found on the
Digital FM Exciter Family Tree, drawing #843-5295-022.
All connections are made at the rear and consist of:
1.2.1.2 The Analog I/O Module
The purpose of the Analog I/O Module is to allow analog inputs
to the digital exciter. This is done by converting the standard
analog inputs into a digital format compatible with the digital
exciter. This module provides input connections for conven12-01-94
Figure 1-1. DIGIT™ Exciter Mechanical Dimensions
• AC Power Input (110, 120, 220 or 240 Volt, 50 or 60 Hz)
• Digital Input, J1 (Includes the necessary voltages and inter-
connects for the Digital Stereo Generator Module or the
Analog I/O Module).
• RF Output (50 ohm BNC)
888-2333-001
WARNING: Disconnect primary power prior to servicing.
1-1
DIGIT™
“Channel Setting and Frequency Adjustment”, and to the frequency chart at the end of that Section.
It should also be noted that while the PLL and VCO functions
used in the DIGIT™ exciter are also used in conventional analog
exciters, the important distinction of DIGIT™ is that the program
modulation is NOT applied to this loop. Program is applied to
the Digital Modulator only. Therefore low frequency audio does
not affect the PLL circuitry in DIGIT™, and all associated low
frequency distortion effects are eliminated.
1.4.2.2 N+1, Frequency Agile Configuration
Figure 1-2. DIGIT™ Exciter System Block Diagram
• Remote Control and Status, J2 (15-pin “D” connector, with
isolation filter)
• Remote Frequency Tuning Input J3, an optional 25-pin “D”
connector with isolation filter. (If this option is not included, J3 is omitted.)
• All audio and SCA inputs will connect to either the Digital
Stereo Generator Module or the Analog I/O Module which is
plugged into the Digital Input J1, on theback panelof theexciter.
1.4 Functional Description
For the following discussion, refer to Figure 1-2.
1.4.1 Input Options
Input to the exciter is through J1 - Data Input, on the Digital
Modulator Board, which is accessed through the back panel of the
exciter. Either the Digital Stereo Generator or the Analog I/O
Module will be mounted on the rear of the exciter (See Available
Options earlier in this section). The purpose of these modules is to
convert the digital or analog input signals (depending on which one
you have) into the 16 bit parallel data used by DIGIT™. The data
input J1 also provides power and timing connections for the Digital
Stereo Generator or the Analog I/O Module.
1.4.2 Digital Modulation Process
DIGIT™ uses a fully-digital modulation process to convert the
digital input (from the input module) to a digital FM carrier, at
approximately 5.6MHz. This is then filtered, and up-converted
to the desired carrier frequency. The on-channel signal is filtered,
then amplified by the 55 watt output PA before being supplied
to the BNC output connector on the back of the exciter.
1.4.2.1 Frequency Selection
Both the up-converter local oscillator frequency (from the PLL and
VCO) and the digital modulator frequency are digitally controlled,
with a minimum frequency increment of 50 Hz. Thus, there is no
field tuning or factory pre-tuning required for this exciter. Setting
to the desired FM channel or changing the channel is accomplished
by setting DIP switches. For More information on setting frequency,
refer to Section V, Maintenance and Alignment, under the heading
1-2
Digital frequency control is also extended to J3, an optional
Remote Frequency Tuning Input, on the rear of the exciter,
permitting the use of DIGIT™ in “N+1" mode, in which a single
exciter or transmitter may be used as back up for several transmitters, moving to the required frequency as it is switched on-line
to substitute for a failed transmitter.
1.4.3 Controls and Indicators
The front panel includes the power output controls, and a digital
metering display which can select forward power (FWD PWR),
reflected power (RFL PWR), PA AMPS or PA VOLTS. The
panel also includes an LED bargraph style modulation meter and
four status alarm indicators. The exciter also has a rear panel
Remote Connector which includes the following:
•
•
•
•
Remote metering signals
Remote status indicator drives
Remote interlock signals and remote muting
RF level control lines
1.5 Explanation of Terms
Each board in the exciter has an assembly number, such as A1,
or A10 etc.. These numbers will be referred to in many places in
the manual. The following is a complete listing of the boards in
the exciter and their assembly numbers (this information can also
be found in the exciter drawing package on drawing number,
843-5295-022, Digital FM Exciter Family Tree):
•
•
•
•
•
•
•
•
•
A1 - RF PA Module
A2 - Regulator Board
A3 - Digital Modulator Board
A4 - Upconverter Board
A5 - Analog I/O Moduleor theDigitalStereo GeneratorModule
(depending on which module is installed on your unit).
A6 - VCO Module
A7 - PLL Board
A8 - 5 MHz Filter Board
A9 - 100 MHz Filter Board
1.6 Performance Specifications
NOTE
Specifications subject to change without notice.
888-2333-001
WARNING: Disconnect primary power prior to servicing.
12-01-94
Section I - General Description
See Sales Brochure at beginning of manual for listing of the
Performance Specifications for DIGIT™.
12-01-94
888-2333-001
WARNING: Disconnect primary power prior to servicing.
1-3
Section II
Installation
2.1 Unpacking
2.2 Introduction
Carefully unpack the exciter and perform a visual inspection to
determine that no apparent damage was incurred during shipping
Retain all shipping materials until it has been determined that the
unit is not damaged.
DIGIT™ is a digitally-modulated FM broadcast transmitter exciter, operating in the 87 to 108MHz band, with a guaranteed
output power capability of 55 watts. The exciter can be operated
with the Digital Stereo Generator Module, allowing full digital
processing of the program signal or the optional Analog I/O
Module can be used in place of the Digital Stereo Generator
Module allowing the use of standard analog audio input connections (Mono or Stereo and SCA’s). In either configuration,
modulation is done in the digital domain. DIGIT™ measures 19"
wide, 7" high and 12.5" deep and may be installed directly in
most modern FM transmitters. Interface to the host transmitter
should not be a difficult task.
The contents of the shipment should be as indicated on the
packing list. If the contents are incomplete or if the unit is
damaged mechanically, or electrically, notify the carrier and
Harris Allied Broadcast (217) 222-8200.
All packing materials must be removed from the equipment
before installation. For general domestic shipment of DIGIT™,
no parts are removed before shipment. If for some special reason
parts are removed, then all removed components are marked to
permit easy reinstallation.
Symbol numbers and descriptions are provided on each removed
component corresponding to the schematic diagram, parts list,
packing list and reference designator or nomenclature stenciled
at the cabinet location of each removed item. Cables and small
parts may be taped or tied in place for shipment. Remove all tape,
string and packing materials used for this purpose.
2.1.1 Removal of VCO Shipping Screws
The VCO is mounted on rubber grommets to provide mechanical
isolation from vibration during operation. For shipment, two
screws are installed on the outside of the VCO box to hold the
VCO in place. These must be removed prior to installation. The
hardware on these screws is captive but the screws are not, and
therefore must be removed completely from the exciter. See the
drawing below.
• Remove the screws holding the top cover of the exciter. The
top cover of the exciter is hinged on the left side of the
exciter (looking from the front).
• Remove the lid covering the VCO assembly by simply
lifting it up.
• Remove the two screws indicated in the figure below.
• Reinstall the cover on the VCO and the exciter top cover.
2.3 Physical Mounting
A front-panel area 7" (4 Rack Units) high by 19" wide is required
for DIGIT™. A convenient rackmount kit with extender rails is
provided. Rack mount kits are also available to allow installation
of DIGIT™ into existing Harris HT or PT Series FM transmitters. A complete listing of the available rack mount kits, and
Harris part numbers, can be found on the Digital FM Exciter
Family Tree, drawing #843-5295-022.
2.4 Cooling Airflow
The rear-mounted cooling fan for DIGIT™ draws cooling air
into the left side of the rear panel, and the heated air is exhausted
from the right-hand side of the exciter. The space chosen to
mount DIGIT™ should provide for this airflow.
2.5 Installation
All connections are made to the rear of the exciter. The space
behind the exciter should be deep enough to permit all cable
connections to retract into the transmitter or cabinet as the exciter
is slid in, and to extend smoothly as the exciter is slid out on its
extender rails.
2.5.1 Power
DIGIT™ will operate with an AC power source which is 50 Hz
or 60 Hz, and at a variety of voltages ranging from 90V to 132V,
or from 198V to 264V. Before applying power to DIGIT™ for
the first time, check the indicator window next to the power input
connector on the rear of the exciter to make sure the power input
is set to your supply voltage. The settings are:
Top View of VCO with Cover Removed
Rev. F: 10-09-96
• 100Vac (For 90 to 110 Vac service)
• 120Vac (For 108 to 132 Vac service)
• 220Vac (For 198 to 242 Vac service)
888-2333-001
WARNING: Disconnect primary power prior to servicing.
2-1
DIGIT™
• 240Vac (For 216 to 264 Vac service)
If you need to change the equipment to a different line voltage
setting, remove the power cord from the power input connector
and open the cover over the voltage indicator using a small
screwdriver or similar tool. Rotate the cylinder inside so that the
desired voltage shows in the window. If you are changing from
a 220/240 Vac to a 100/120 Vac range, you should also change
the fuse.
Only one fuse is used in DIGIT™. It is located in the upper fuse
holder beneath the cover. The correct values are:
• 220/240Vac: Use 2 Ampere SlowBlow
• 100/120Vac: Use 4 Ampere SlowBlow
Both fuse values are supplied with the exciter. The value not
installed in the fuseholder is mounted to a clip on the rear of the
case.
NOTE:
Some 220/240 Vac users require both conductors of the power
lead to be fused. The lower fuse-holder in the power input connector is not used, but can be equipped with a second 2 Ampere
Slowblow fuse, and the second conductor may be routed through
this fuse.
When the line voltage setting and the fuse value have been
correctly selected for your service, close the cover and reinsert
the power cord.
2.5.2 Digital Stereo Generator Module (A5)
The Digital Stereo Generator Module requires an AES/EBU
compatible digital stereo audio signal, with the option of two
SCA and a RBDS (Radio Broadcast Data System) input. The
module attaches to the right rear panel of the exciter. All inputs
are on the side of the interface module next to the fan.
2.5.2.1 Program, SCA and RBDS Inputs
The program and SCA inputs to DIGIT™ will connect to the
Digital Stereo Generator Module, mounted on the right rear of
the exciter cabinet. The digital audio input requires a male XLR
connector while the SCA and RBDS input connections are BNC.
The connections available are: (See Figure 2-1)
• J2 SCA1
• J3 SCA2 (Also serves as Analog Backup Input)
• J4 RBDS Input
• J9 AES/EBU Digital Input
2.5.2.2 Digital Audio Input Connector, J9
J9, XLR pinout is as follows: (refer to sheet 1, Digital Stereo
Generator Schematic)
J9-1 - Ground
J9-2 - (+)
J9-3 - (-)
J9-4 - Ground
2.5.2.3 I/O and Remote Control, J7
Some of the inputs on this connector are in parallel with the S1
dip switches shown in Figure 2-1. If this connector is used, the
corresponding sections of dipswitch S1 should be placed in the
open or “OFF” position (this is the way the unit is shipped). The
pre-emphasis switches, S1-2 and S1-3 are not affected by connector J7.
• J7-1 - Supplies +5Vdc for pull up use.
• J7-9 - Ground
Status Output
• J7-3 - This is a PLL Unlock status output. Any unlock
conditions or any AES/EBU communication faults bring
this output high, or +5V. For example, a disconnected
AES/EBU cable will activate this fault.
Control Inputs
Figure 2-1. Digital Stereo Generator Component Locator
2-2
888-2333-001
WARNING: Disconnect primary power prior to servicing.
Rev. F: 10-09-96
Section II - Installation
• J7-2 - A high on this input will place the unit in stereo mode.
A low will place the unit in mono mode.
• J7-4 - A high on this input will select the digital audio input
at J9. A low will select the Analog backup input at J3, which
is normally the SCA2 input. This does not automatically
switch the SCA2 input to a backup analog signal. The
normal SCA2 input must be removed from J3 and an
appropriate analog composite signal connected. To make
the analog backup function completely remote controlled,
an external analog sorce switch, such as a coaxial relay, will
need to be used to switch from the normal SCA2 subcarrier
signal to the backup analog composite signal. The external
analog source switch should be made to activate after or at
the same time as the switching signal to J7-4. The analog
source switch should not be activated before the interface
module is switched to the backup mode.
• J7-5 - A high selects internal control of limiting level, via
LIMIT pot on top of the module. A low selects the use of
an external limit level input voltage at J7-6, to control the
limiting level instead of the internal control pot.
• J7-6 - Can be used to input a voltage which will control the
amount of composite limiting. The voltage on this input
will only be used to control limiting when J7-5 is pulled
low. The input range of this voltage is 0 to +5V, and should
never exceed the +5V level. A higher voltage means more
limiting.
• J7-8 - A high selects limiting to be displayed on the LED
meter on top of the module. A low selects percent deviation
to be displayed on the LED meter on top of the module.
Note
A high can be either a +5V input or high impedance for all J7
inputs.
For more information on the these controls refer to Section IV,
Theory of Operation.
2.5.2.4 Pre-emphasis Selection
The exciter may be operated at flat response, or with 25, 50 or
75us pre-emphasis on the AES/EBU input. Two sections of S1,
located inside the interface module, are used to make the selection per Table 2-1. For switch location refer to Figure 2-1.
S1-2
off
off
on
on
S1-3
off
on
off
on
Pre-emphasis
No pre-emphasis
25us pre-emphasis
50us pre-emphasis
75us pre-emphasis
Table 2-1. Pre-Emphasis Switch Selection
for Digital Stereo Generator Module
2.5.3 Digital Stereo Generator Module Alignment
Procedure
2.5.3.1 Select Operational Mode (Dip Switch settings)
The factory setting for the Digital Stereo Generator Module is
the following:
Figure 2-2. Digital Stereo Generator Module
Adjustments and LED Locations
2.5.3.1.1
Mono Mode
If the exciter is going to be used in Mono Mode, then it is
recommended that the remote connector J7 be used to put the
exciter in the Mono Mode of operation. Mono mode is selected
by grounding J7-2.
2.5.3.1.2
Analog Backup Mode
The module also has a backup or emergency analog composite
input mode. If the digital signal link is interrupted for some
reason, maybe the loss of the digital STL link, the module may
be placed in the analog backup mode either locally, with a dip
switch setting inside the module, or remotely via J7, on the side
of the module. An analog composite signal may then be input in
place of the SCA2 signal. Broadcasters who do not yet have a
full digital link to the transmitter site can use the exciter in this
mode indefinetly, or until such time as they can upgrade their
system from analog to digital.
NOTE: SCA inputs can still be used in this mode but must be
reduced in amplitude by 16dB due to the increased gain required
to accommodate the analog composite input.
More information is given in Section 4, Theory of operation, and
an emergency change over procedure is included in Section III,
under Emergency Operating Procedure.
It is recommended that the remote connector J7 be used to select
the Analog Backup Mode of operation (if so desired). Analog
Backup mode is selected by grounding J7-4.
Stereo mode selected
AES/EBU input mode selected
No Pre-emphasis
Rev. F: 10-09-96
888-2333-001
WARNING: Disconnect primary power prior to servicing.
2-3
DIGIT™
2.5.3.1.3
Pre-Emphasis and Permanent Mode Selection
If the pre-emphasis setting needs modification or a permanent
switch setting is desired for the MONO or ANALOG backup
mode then do the following:
• Disconnect power from the exciter and all connections from
•
•
•
•
•
•
•
the Digital Stereo Generator Module.
Remove the four large mounting screws holding the Digital
Stereo Generator Module to the back of the DIGIT™ exciter.
Remove the module from the exciter by gently pulling the
module straight out from the back of the exciter.
Position the stereo generator so that the connector pins are
facing up.
With a small screw-driver, unscrew the four screws recessed in the black modular box. Gently separate the modular box by removing the top half from the bottom half.
Identify the 8 position dip switch S1 on the PC board, as
shown in Figure 2-1.
Position the S1-2 and S1-3 dip switches for the desired
pre-emphasis using Table 2-1.
Position the mode switches, S1-1 and S1-4, for the desired
operational mode, per Table 2-2.
Switch
S1-1
S1-4
Position
OFF
ON
OFF
ON
Mode
Stereo
Mono
AES/EBU Digital Audio Input
Analog Backup Mode
Table 2-2. Digital Stereo Generator Module
Mode Selection
• Carefully replace the top cover on the box making sure all
dividers are inserted properly.
• Screw the box together again using the four recessed
screws.
• Check the connector pins to ensure there are no bent or
crooked pins.
• Carefully mount the box onto the exciter using the four
alignment pins as guides. Be careful during the initial
mating of the connector pins.
• Secure the box onto the exciter using the four mounting
bolts.
• Reconnect cables and re-apply power.
2.5.3.2 Setting SCA and Pilot levels
All SCA inputs are preset to accept a 1.5V peak-to-peak nominal
input for 10% injection. The Pilot control is preset to provide
10% injection. All adjustments are on the top of the interface
module and are clearly silkscreened. A drawing of the top of the
module is shown in Figure 2-2. To verify that the SCA and Pilot
levels are correct, or to change the SCA and/or Pilot levels do
the following:
• Disconnect or turn off the AES/EBU input.
• Adjust the pilot pot all the way counter-clockwise (this sets
the pilot level to 0).
• Apply the desired analog signal (1.5Vpp nominal) to either
•
•
•
SCA1, SCA2, or the RBDS input.
Adjust the SCA pot for the desired deviation as read on the
exciter front panel modulation meter.
Disconnect the SCA input.
Adjust the Pilot level to the desired deviation as read on the
exciter front panel modulation meter.
Re-apply the SCA input signal and the AES/EBU input.
•
2.5.3.3 Setting the Output Deviation and Limiting Level
Refer to Figure 2-2 for the following adjustments. The output
deviation is factory preset to 100% (assumes 10% pilot and no
SCAs). The limiter is factory pre-set for 1dB of limiting, but this
assumes a full scale AES/EBU input of 0dBFS (0dB Full Scale,
HEX 7FFF). If your nominal digital input level is 0dBFS, then you
need only to set the amount of composite limiting desired with the
LIMIT level pot. The limiting can be set anywhere from no limiting
to a maximum of 18dB. To verify these settings or to change them
do the following (minimum input level is -10dBFS):
• Disconnect or turn off any SCA inputs.
• Apply a nominal AES/EBU input to the Digital Stereo
Generator Module.
• Turn the LIMIT level pot fully CW.
• Adjust the DEV level pot until the desired output modula-
tion reading on the exciter front panel modulation meter is
obtained.
Figure 2-3. Analog I/O Module Inputs
2-4
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WARNING: Disconnect primary power prior to servicing.
Rev. F: 10-09-96
Section II - Installation
Figure 2-4. Remote Voltage Output Versus
Fwd Pwr, RFL Pwr, PAV and PAI
• Re-adjust the LIMIT pot until the desired limit reading is
obtained on the Stereo Generator Module LED display. The
five LEDs represent 1dB, 2dB, 3dB, 4dB and 5dB of
limiting. If the LIMIT pot is turned further CW, the amount
of limiting can be increased up to 18dB (only the LED
display is limited to 5dB).
• Use the DEV level pot and the exciter front panel modulation meter to fine tune the deviation if required.
• Re-apply any SCA input signals.
The Digital Stereo Generator Module is now aligned.
JP1
off
off
on
on
JP2
off
on
off
on
Pre-emphasis
No pre-emphasis
25us pre-emphasis
50us pre-emphasis
75us pre-emphasis
Table 2-3. Pre-Emphasis Jumper Selection
for Analog I/O Module
2.5.4 Analog I/O Module (A5)
In the analog input configuration, DIGIT™ has an Analog I/O
module attached to the right rear of the enclosure and all analog
inputs are on the edge of the interface.
2.5.4.4 Input Cables
2.5.4.1 Program and SCA inputs
Coaxial cables with BNC connectors may be used to connect to
the unbalanced inputs. If right-angle BNC connectors are not
available for the DIGIT™ end of the cables, right-angle BNC
adapters may be used to connect the cables to the Analog I/O
Module connectors. These may be obtained locally.
The program and SCA inputs to DIGIT™ will connect to the
Analog I/O Module, mounted on the right rear of the exciter
cabinet. All input connections are BNC, located on the left side
of the Analog I/O Module, between it and the cooling fan. The
connections available are:
• J2 SCA1
• J3 SCA2
• J4 SCA3
• J5 Unbalanced Composite
• J6 Balanced Composite
• J7 Monaural Input
2.5.4.2 Input Specifications
• Monaural: +10 dBm, 600 ohms (75 kHz)
• Composite: 3.5 V P-P 10K ohms (75 kHz)
• SCA:
1.5 V P-P 10K ohms (7.5 kHz)
Note
There is no internal adjustment for the SCA input levels. Each
SCA input is set to provide 7.5kHz deviation with a 1.5Vp-p input.
2.5.4.3 Pre-emphasis Jumper
The exciter may be operated at flat response, or with 25, 50 or
75us pre-emphasis in the Monaural channel. JP1 and JP2 are used
to make the selection per Table 2-3. The unit is shipped with no
pre-emphasis.
Rev. F: 10-09-96
All input connections to Analog I/O Module A5 are to BNC
connectors along the edge of the module adjacent to the blower,
see Figure 2-3.
To connect to the balanced inputs (Monaural or Balanced Composite), a special cable must be constructed, with the outer shield
isolated from the connector and terminated in a pigtail which
connects to the ground stud nearby. These cables may be ordered
ready-made in several standard lengths from Harris-Allied, with
BNC connectors installed on both ends. Use the following part
numbers when ordering:
922-0014-001
922-0014-002
922-0014-003
922-0014-004
922-0014-005
922-0014-006
- 2.5 ft.
- 5 ft.
- 10 ft.
- 15 ft.
- 25 ft.
- 40 ft.
2.5.4.5 Setting Modulation Level
The Balanced and Unbalanced Composite, and the SCA input
levels are basically fixed (see Input Specifications above). The
MOD LEVEL control should not be moved unless a different
Composite and SCA input level is required, as the MOD LEVEL
is an overall gain control which will change both at the same
time. There is no separate gain control for the Composite and
SCA inputs. If the Composite and SCA inputs are requiring other
than the levels stated above in “Input Specifications”, then refer
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WARNING: Disconnect primary power prior to servicing.
2-5
DIGIT™
•
•
•
•
•
J2-1 Ground
J2-2 Remote FWD PWR Meter Drive
J2-3 Remote RFL PWR Meter Drive
J2-4 Remote PAV Meter Drive
J2-5 Remote PAI Meter Drive
The remote meter drives each provide outputs of 0 to +4 Volts
which may be used to operate a remote metering device such as
a remote control system, see Figure 2-4.
Remote FWD PWR Meter Drive Level Adjustment
Figure 2-5. Exciter Front Panel & Forward Power
Calibration & Adjustment Pot Position
to Section V, Maintenance and Alignment under the heading
“Input Signal Level Calibration”.
• Modulation level should be set by adjusting the input signal
level to the Analog I/O Module until the desired modulation
is obtained, NOT by adjusting the MOD LEVEL control as
this will also affect SCA injection.
Note
If the SCAs have already been combined into the composite input, then the MOD LEVEL pot may be used to set deviation.
2.5.4.5.1 Setting Monaural Level
The Monaural audio input does have a separate gain control. It
is factory set to give a 100% modulation reading with a nominal
+10dBm input at 400Hz. Input adjustment is provided via R19
and allows inputs to range between -9.17dBm and 14.4dBm
assuming the Modulation Level adjustment (R26) is set at the
nominal setting of 0dB gain. Inputs above 14.4dBm are clipped.
• Input a nominal line level signal into the monaural input
and adjust the MONO LEVEL pot, R19, for a 100% reading
on the front panel modulation meter. If the MOD LEVEL
control is changed, the monaural level will have to be
re-adjusted.
2.5.5 Exciter RF Output
The RF output from the exciter is a BNC connector, J1, on the
rear panel of the exciter. Connect J1 to the drive input of the
system being driven by DIGIT™. The front panel buttons are
used to set the power output of the exciter to the level required
by the transmitter. For more information on how to set exciter
output power level, refer to Section III, Operation. If an external
power control (APC) will be used, refer to Section V, under the
heading “Exciter APC.”
2.5.6 Remote Metering and Control, J2
A 15-pin “D” REMOTE connector, J2, is located on the rear
panel of the exciter. J2 contains remote metering signals, remote
status indicator drives, remote interlock signals and remote muting and RF level control lines (APC).
There is an optional Remote Cable Adaptor Kit, Part# 992-8941001, which can be used to facilitate remote interfacing, especially
with non-Harris transmitters. It basically consists of a 5ft. cable
and a breakout terminal strip.
The connections available at J2 are as follows:
2-6
The Remote FWD PWR Meter Drive level at J2-2 is adjustable
via R55 on the Regulator Board. This adjustment is accessible
from the top of the exciter on the front right hand corner. See
Figure 2-5. With the exciter output power set to 50 Watts,
connect the VOM to J2-2. Adjust R55, Forward Remote, as
needed to produce 3.33 VDC at J2-2 (Maximum output is 4 VDC
at 60 watts).
Note
To accommodate HT35 transmitter requirements, set the exciter
output to 8.2 Watts. R55 should be adjusted to provide a 1.34
Volt output for normal HT35 operation.
• J2-6 Remote FAULT
Remote FAULT is an open collector output capable of sinking
100mA through a pull-up resistor connected to +5V. The
FAULT signal is true if a PLL Unlock, Temperature Fault or
VSWR Fault exists. The Fault True condition may be set to be
either a HIGH or a LOW by setting JP3 on the Regulator board.
1-2 selects active LOW (the fault condition produces a LOW),
and 1-3 selects active HIGH. The factory setting is active low,
pins 1-2 (except for exciters installed in PT series transmitters
which are required to have active high outputs).
• J2-7 Ground
• J2-8 Exciter APC
This is an input used to control exciter power remotely. 4V
applied to this terminal should produce an exciter output of 60
watts. Output decreases linearly as the voltage at Pin 8 is lowered.
The remote APC control feature is enabled by setting Regulator
board jumper JP2 to 2-3. Setting the Jumper to 1-2 disables the
remote power control.
APC Adjustment
This adjustment is required only if your transmitter or your
system uses the exciter APC connection, J2-8, to control the
exciter output power. This potentiometer adjusts the APC voltage when external power control is being used. The adjustment
provides only attenuation and cannot increase the APC voltage.
The APC voltage must be greater than 2.5V to achieve 50 Watts
of output power. Adjustment is best performed at the system
level.
The adjustment procedure is as follows:
Using the transmitter or a test power supply, connect to J2-8 the
DC voltage which is to cause the exciter output to be 50 Watts.
Adjust R6, Exciter APC, until the exciter output is 50 watts, as
read on the front panel display. R6 is located on the front right
corner of the exciter, see Figure 2-5.
• J2-9 RF MUTE
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WARNING: Disconnect primary power prior to servicing.
Rev. F: 10-09-96
Section II - Installation
MUTE is a TTL/CMOS compatible input which may be used to
interrupt the exciter’s RF output. JP1 on the Regulator board can
be set to select whether MUTE takes place when Pin 9 is either
HIGH or LOW. Connecting JP1, 1-2 causes a LOW on pin 9 to
mute the exciter; connecting JP1, 2-3 causes a HIGH to mute the
exciter. The factory setting is active low, pins 1-2 (except for
exciters installed in PT series transmitters which are required to
have active high outputs).
• J2-10 AFC INTERLOCK COMMON
• J2-11 AFC INTERLOCK NC
• J2-12 AFC INTERLOCK NO
Automatic Fault Control (AFC) Interlock turns off the exciter
when an exciter fault occurs, and also switches relay K1 on the
Regulator board. NC, Common, and NO connections from K1
are brought out to Pins 10, 11 and 12 to allow interfacing to
external equipment. The relay contacts are capable of switching
0.25 Amperes at 100 Volts.
• J2-13 NOPGM
NOPGM is an open collector output capable of sinking 100mA
through a pull-up resistor connected to +5V. A High (Open) at
this pin indicates there is no digital modulation input to the
exciter.
• J2-14 (Unused)
• J2-15 Ground
2.5.7 Remote Frequency Select, J3 (Optional)
DIGIT™ may be ordered with J3, an additional 25-Pin “D”
connector, installed, allowing the exciter’s frequency to be set
remotely. This feature is used for “N+1, Frequency-Agile applications. The connections from J3 are routed to the Digital Modu-
Rev. F: 10-09-96
lator and the PLL boards and are connected in parallel with the
frequency select DIP switches on those boards.
• Pins 1 through 12 of J3 select the Digital Modulator fre-
quency using the same selection chart used for S2, S3 and
S4 on the Digital Modulator. N0 (N-zero), the low-order
bit, is Pin 1, and N11, the High-Order bit, is pin 12.
• Pins 16 through 25 of J3 select the LO frequency using the
selection charts used for S1, S2 And S3 on the PLL board.
M0, the Low-Order bit, is Pin 16, and M9, the High-Order
bit, is Pin 25.
• The frequency selection chart is included at the end of
Section V, Maintenance and Alignment.
If remote frequency select is to be used, a suitable remote select
switch must be connected to J3, and the internal select switches
(S2, S3 and S4 on the Digital Modulator and S1, S2 and S3 on
the PLL) must all be set to OPEN. The external select switch can
then be used to set the exciter to any frequency between 87.8
Mhz and 108 Mhz. A Remote Frequency Control Kit is available,
Part# 994-9478-001
• J3-13 supplies +5 volts through a 100 ohm current-limiting
resistor to the external switching circuits.
• J3-14 supplies ground.
• J3-15 Provides an additional MUTE connection for use by
N+1 or other remote frequency-control circuitry. When
used, the mute connection requires a LOW to enable the
exciter output, and a HIGH (or an open wire) disables the
output. When this MUTE circuit is not needed, placing
regulator board jumper JP4 in the 1-2 position supplies the
ground, permitting the exciter to operate.
For more information on frequency selection, both remote and
local, refer to Section V, Maintenance And Alignment.
888-2333-001
WARNING: Disconnect primary power prior to servicing.
2-7
Section III
Operation
3.1 Introduction
3.3 Modulation Level
The DIGIT™ front panel is shown in Figure 3-1. The panel
includes a 3 1/2 segment LCD display window with four control
buttons directly below it, a bar-graph displaying percent of
modulation with an indicator directly below it which lights when
modulation is below 15%, and four red fault status indicators.
The bar-graph at the center of the LCD display is made up from
3 10-segment LED’s. The Left and center LED’s are green and
the right LED is red.
3.2 Fault Indicators
There are four red LED fault indicators at the left of the front
panel.
• RF MUTE lights if the exciter output is muted by:
• An exciter fault condition which lights the PLL indicator
The bar-graph displays % modulation in 5% steps, and the first
red LED indicator represents 100%.
Below the bar-graph is an additional “/10" indicator which lights
if modulation level is below 15%. When the “/10" indicator is
lit, the first red LED indicates 10%, and each step represents
0.5%. The display sensitivity is auto ranging so as soon as a
modulation peak exceeds 15% the “/10" light goes out and the
bar-graph returns to the normal 100% display.
(see PLL below).
• an external command from Remote connector J2-9
• an external command from the optional Remote Frequency
Control connector J3-15 (N+1 Mute).
• SWR lights if the coupler in the output of the 55 Watt PA
detects more than 5 watts reflected power.
• TEMPERATURE lights if the PA heat sink temperature
exceeds 80 degrees C.
• PLL lights and the exciter output is muted if one of the
following conditions exists:
PLL Board unlock
Upconverter Fault
100 MHz Filter fault
5 MHz Filter fault
3.4 Metering and Control
The LCD display and the four buttons below it select:
•
•
•
•
FWD PWR
RFL PWR
PA AMPS
PA VOLTS
(SET)
3.5 Power Adjustment
The middle two buttons are used along with the FWD PWR or
SET button to adjust the power output.
To raise power output, press and hold SET and momentarily
press the Raise (up-arrow) button. The exciter power will raise
Figure 3-1. DIGIT Exciter Front Panel
12-14-94
888-2333-001
WARNING: Disconnect primary power prior to servicing.
3-1
DIGIT™
slightly. Continue to pulse the Raise button until the desired
output is reached. If the Raise button is pressed and held the
power will change more rapidly.
To lower power output, press and hold SET and momentarily
press the Lower (down arrow) button. The exciter power will
lower slightly. Continue to pulse the Lower button until the
desired output is reached. Pressing and holding the Lower button
will lower power more rapidly.
3.8 Emergency Operating Procedure
If the exciter is using the Digital Stereo Generator module and
the digital audio input, and the digital audio signal is lost, the
module may be placed in the Analog Backup Mode. This will
allow the insertion of an analog composite signal into the SCA2
input, to get the exciter, and the transmitter, back on the air. All
other audio input signals must either be reduced by 16dB or be
disconnected (turned off) while in the Analog Backup Mode.
3.8.1 Switching to the Analog Backup Mode
There are two ways to switch to the Analog Backup Mode.
3.6 Display Test
The LCD display and the four Fault indicators may be tested by
pressing and holding the FWD PWR button, and also pressing
the right-hand (PA VOLTS) button. This will turn on all segments of the LCD display and the fault indicators for as long as
both buttons are held.
3.7 DC Power Indicators
The illuminated front-panel DIGIT™ logo in the upper right
corner also serves as the DC power indicator. All four voltage
regulators within DIGIT™ are used to power the LED’s behind
the logo, and failure of any of the supply voltages will cause part
of the logo to be dark. The LED’s powered by each voltage are:
+17V
3-2
-17V
+6.5V
-6.5V
a. The first method is to ground pin 4 of J7, the Remote
connector on the side of the Digital Stereo Generator
Module. This will place the interface module in the analog
backup mode, and turns the SCA2 input, J3, into an analog
composite input. The signal source for J3 must be switched
externally by the user, after the interface module is placed
in the analog backup mode.
b. The second method is only to be used if the Digital Stereo
Generator Module is to be used for an extended period of
time in the analog backup mode. For this method it is
necessary to remove and open the Digital Stereo Generator
Module, and set S1-4 to the ON position. The use of the
remote connector J7, is preferred if the units normal mode
of operation is to use the digital audio input.
Now that the Module is in the Analog Backup Mode:
c. A 3.5Vpp (nominal for 75kHz deviation) analog composite
signal, should be applied to the SCA2 input as the backup
signal. Other SCA/RBDS inputs can be used, but each one
must be reduced in amplitude by 16dB due to the increased
gain required to accommodate the analog composite input.
S/N will also be reduced by 16dB for these inputs. If over
modulation occurs, reduce the input level to the exciter.
888-2333-001
WARNING: Disconnect primary power prior to servicing.
12-14-94
Section IV
Theory of Operation
4.1 General Description
The DIGIT™ Digital FM Exciter inputs a digital composite
stereo signal from one of two input interface modules and
generates an on carrier FM signal at power levels up to 55W. It
is frequency agile and can be used in N+1 configurations. Performance limitations of the Digital to Analog (DAC) technology
require the digital FM generation be done at a low frequency IF,
then upconverted to the desired channel frequency. The exciter
is adaptable to all analog exciter applications by using the optional Analog I/O Module.
4.2 Block Diagram Description
Figure 4-1 is the simplified overall block diagram for DIGIT™.
DIGIT™ is enclosed in a cabinet containing power supplies,
control logic and all signal processing and amplification needed
to convert the 16-bit digital audio source into an on-channel
frequency modulated signal. The input to DIGIT™ is a 16 bit
composite digital signal. All inputs to DIGIT™, whether digital
(AES/EBU compatible) or analog, must be converted to a compatible 16 bit signal. This can be done by either the Digital Stereo
Generator Module, for digital signal inputs, or with the Analog
I/O Module, for conventional analog signals.
4.2.1 Input Options
There are two input modules available for use with DIGIT™.
The Digital Stereo Generator Module and the Analog I/O Module.
4.2.1.1 Digital Stereo Generator Module (A5)
The Digital Stereo Generator Module accepts one AES/EBU
24-bit digital stereo input and convert it to the 16-bit digital
composite stereo signal which is then be supplied to J1 and the
Digital Modulator. It also provides for an analog composite input
as a backup for the digital AES/EBU input. The interface features
a DSP based stereo generator that delivers a “CD” quality digital
composite signal to the exciter. Two analog SCA inputs and an
RBDS input are also provided. The analog SCA and RBDS
inputs are digitized and added to the high quality digital composite signal. (A 19kHz pilot sync is output for RBDS generator
use). A low distortion composite limiter is also provided, along
with an LED display on top of the module to show the amount
of limiting being used. User adjustments are available for pilot
injection, composite limiting, output deviation, composite
equalization, and SCA/RBDS level controls. The Digital Stereo
Generator mounts on the DIGIT™ back panel. All input signals
are summed, converted to 16-bit composite digital and routed to
the Digital Modulator board in the exciter.
4.2.1.2 Analog I/O Module (A5)
If the exciter is to receive an analog input, the Analog I/O Module
Option is installed on the right rear panel, instead of the Digital
Stereo Generator Module, connecting to the Data Input connector J1. The Analog Interface Module provides 6 analog inputs
Figure 4-1. Overall Block Diagram
Errata: 01-05-95
888-2333-001
WARNING: Disconnect primary power prior to servicing.
4-1
DIGIT™
via external BNC connectors. They are the Balanced Composite
Input, the Unbalanced Composite Input, SCA 1, SCA 2, SCA 3,
and the Monaural input. Any combination of these inputs may
be connected to the Analog I/O Module, and the signals are
summed, converted to 16-bit composite digital and routed to J1
and the Digital Modulator board.
4.2.2 Digital Modulator Board (A3)
This module receives and processes the 16-bit parallel digital
audio signal and generates a 5.6 Mhz frequency-modulated
carrier. The carrier is filtered to remove the alias frequency
components. “Fine Frequency” switches (S2, S3 and S4) are used
to select the exact frequency (approximately 5.6 MHz) of the
digital modulator board output. When Remote Frequency Tuning (N+1) operation is used, the remote command sets this
frequency, with all sections of S2, S3 and S4 set to OPEN. The
exact output frequency of this board can be found using the
information in Section V, under the heading, Digital Modulator
Switches.
Also included in the Digital Modulator Board are a Digital Peak
Detector and drive circuits for the front panel bargraph modulation meter.
4.2.3 5 MHz Filter Board (A8)
The 5.6 MHz FM output signal from the digital modulator is
filtered in the 5 MHz filter board. The filter attenuates any
undesired modulation products.
4.2.4 PLL Board (A7)
DIGIT™ uses frequency synthesis techniques to avoid the need
for channel-specific crystal selection. The PLL board uses a
10MHz reference oscillator for the phase locked loop. The Phase
Locked Loop (PLL) is set to the correct frequency by setting DIP
switches S1, S2 and S3. These are the “Course Frequency”
switches, which set the PLL frequency to at least within 125kHz
of the carrier frequency. The “Fine Frequency” switches on the
Digital Modulator, are then used to set the exact exciter output
frequency from 87.8 MHz to 108 MHz.
When Remote Frequency Tuning (N+1) operation is used, the
remote command sets this frequency as well as the Digital
Modulator frequency, and all sections of S1, S2 and S3 are set
to OPEN.
4.2.5 VCO Module (A6)
The error voltage from the PLL board is applied to varactors
which control the frequency of the VCO. The VCO output is
buffered and fed back to the PLL Board. The VCO output is the
LO (Local Oscillator) frequency for the upconverter. The VCO
Frequency will be determined by the frequency setting dip
switches on the PLL board. All inputs and outputs for the VCO
Module come from the PLL Board (including supply voltages).
4.2.6 Upconverter Board (A4)
The Up-converter is supplied with the 5.6 MHz (approximately)
modulated FM input from the 5 MHz Filter board, and also the
Local Oscillator input from the PLL Board. Both signals are
amplified, filtered and then applied to a mixer which produces a
4-2
product 5.6 MHz above, and a product 5.6 MHz below, the LO
frequency. Only the upper product is used.
The mixer output is filtered and fed to the first 100MHz Filter
Board (actually part of the Upconverter assembly, A4) to remove
mixing products.
4.2.7 100 MHz Filter Board (A9)
To ensure purity of the output signal, the on-frequency carrier
signal is filtered again on this, the second 100 MHz Filter board.
This circuit is identical to the first 100MHz filter circuit on the
Up-converter board. The output of this board feeds the RF PA
input.
4.2.8 55 Watt PA Module (A1)
All signal processing to this point in DIGIT™ has been at low
levels. The input level to the 55 Watt PA is approximately
+0dBm. The PA amplifies the second 100 MHz filter output to
the required output level. The amplifier utilizes a hybrid amplifier device to achieve high input gain, followed by a bipolar
transistor, driving an FET output device. Forward and Reflected
directional couplers are included in the output circuit.
Design of the amplifier is very conservative, with power capability beyond the 55 Watt level.
4.2.9 Regulator Board (A2)
The regulator board, mounted to the back of the front panel,
contains the bargraph modulation meter and LCD displays with
their drivers, the fault indicators, the microprocessor controller,
the remote control interfacing circuits, and the power regulators.
The regulator board contains the following adjustments, which
may be reached through the top of the case: (see Figure 4-2)
• R6 - Exciter APC - adjusts the range of the APC input
voltage to allow it to generate the required power output.
• R56 - Forward Meter - calibrates the front-panel forward
power meter display.
• R55 - Forward Remote - calibrates the remote metering
voltage for forward power.
For adjustment information refer to Section V, under the heading, Exciter Power Level and Power Metering.
4.2.10 Remote Frequency Tuning Input, J3 (Optional)
A Filtered rear mounted 25 pin D connector provides the interface for Remote Frequency Tuning. A Remote Frequency Control Kit is available for N+1 applications, Part# 994-9478-001.
Note
If the exciter is meant for fixed frequency operation (will not be
used for N+1) then the J3 connector will not be installed on the
exciter.
The input must be driven by a TTL/CMOS compatible interface.
Changes in the tuning number may be done asynchronously but
the settling time for any tuning changes is required to be less than
400ns to avoid large transitional errors in output frequency. Each
line is active high. The inputs at J3 are used to replace the internal
frequency dip switches on the Digital Modulator Board and the
PLL Board. When the remote frequency tuning is used, the
frequency switches on those two boards are placed in the open
888-2333-001
WARNING: Disconnect primary power prior to servicing.
Errata: 01-05-95
Section IV - Theory of Operation
accurate to within 2% at full scale. The Remote Forward Power
can be set to within 1% at full scale assuming a VSWR of 1:1.
There is no accuracy specification for Reflected Power.
4.2.11.2 Exciter Fault and No Program Status (Fault, NoPgm)
Figure 4-2. Exciter Front Panel & Forward Power
Calibration & Adjustment Pot position
position. A complete pinout of J3 can be found on the Interconnect Diagram in the drawing package (Drawing #843-5295-001).
The recommended switch settings for all channels is given in
Section V, Maintenance and Alignments, in a chart at the end of
the section.
4.2.11 Remote Control and Status, J2
Remote control inputs and exciter status outputs are provided via
a filtered 15 pin rear mounted D connector, J2.
Status outputs include:
•
•
•
•
•
•
Forward power
Reflected power
PA voltage
PA current
Exciter Fault Indication
No program data
The control inputs are:
• Automatic Power Control (APC)
• Exciter Mute
• Automatic Fault Control (AFC) interlock
4.2.11.1 Exciter PA Status (FWD PWR, RFL PWR, PAV, PAI)
These status outputs provide an output voltage which varies
linearly between 0 and +4V as shown in Figure 4-3. For example
if the PA voltage was 16 volts, then 2.0V would be applied to
J2-4. The Remote PA volts and remote PA current are specified
These status outputs are open collector outputs capable of sinking over 100mA with a pull up resistor to +5 Volts. A high (+5V)
on J2-6 indicates that an exciter fault (PLL unlock, Temperature
fault, or VSWR fault) has occurred. A high (+5V) on J2-13
indicates that there is no digital modulation input to the exciter.
The no program (NoPgm) status is useful in determining input
source faults. If the exciter has no digital modulation input for at
least 4.2 seconds then this remote output is driven high. The
signal will return to 0 volts as soon as a digital input is again
detected, at the input to the Digital Modulator Board.
4.2.11.3 Exciter Mute (Mute)
This input must be TTL/CMOS compatible and can be active low
or high depending on the position of jumper JP1 on the exciter’s
regulator board. When activated it will mute the exciter (disable
output power).
4.2.11.4 Automatic Power Control (APC)
This input is used to control the exciter power remotely. The
input requires at least a 4V level (into a 10k ohm load) to achieve
an exciter power level of 60W. Higher input voltages are acceptable as long as the APC adjustment pot (R6) on the regulator
board is correctly adjusted to provide the required 4V dc at the
A/D input (the A/D voltage is clamped at 5.1Vdc in case of
accidental excess voltage). The exciter output power will increase linearly relative to the APC input voltage assuming the
previously mentioned conditions are met. The scale is identical
to the forward power curve of Figure 4-3.
4.2.11.5 Automatic Fault Control Interlock (AFC Com,
AFC NC, AFC NO)
A reed relay switch is provided for the use of the transmitter.
When an exciter fault occurs, the exciter will shut off output
power and switch the relay. The relay is capable of switching a
maximum of 0.25 Amps at 100V. The voltage must not exceed
250V, and the current must not exceed 1A.
Figure 4-3. Remote Voltage Output Versus
Fwd Pwr, RFL Pwr, PAV and PAI
Errata: 01-05-95
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WARNING: Disconnect primary power prior to servicing.
4-3
DIGIT™
4.2.12 RF Output
The RF output is a 50 ohm BNC output with optional N-type
connector. The output power is variable from 3 Watts to 55
Watts. Frequency can range from 87MHz to 108MHz.
4.2.13 AC Input
The AC input will accept either 110V or 240V, 50Hz or 60Hz.
Voltage ranges from 90Vac to 132Vac or 198Vac to 264Vac are
accommodated by high and low line voltage settings in the ac
input. The ac input is fused at 10A.
4.2.14 Regulated Power Supplies
There are four regulated supplies, +17VDC, -17VDC, +6.5VDC
and -6.5VDC, which are distributed throughout the exciter.
These are in turn regulated down to 15 and 5 volts respectively,
on each individual board.
4.3 Detailed Description
4.3.1 Front Panel Interface
The front panel provides a 3-segment LCD display for metering,
and a 30 LED modulation meter. In addition 4 user buttons to
change metering functions, 4 fault indicators, and a 10% modulation indicator are provided. Finally, four dc power indicators
comprising the logo LED are visible for easy power supply
failure detection.
4.3.1.1 Front Panel Controls
The four front panel buttons control the following functions as
given below:
Function
Display PA volts
Display PA Current
Display Reflected Power
Display Forward Power
Increment Forward Power
PWR] Buttons
Decrement Forward Power
AMPS] Buttons
Test Mode
4.3.1.3 Modulation level
The bargraph modulation meter allows 5% modulation increments in full scale mode, and 0.5% increments in 10% (/10
indicator lit) scale mode. It uses a precise digital peak detection
circuit that provides a 100% modulation reading with an accuracy of approximately 0.2%.
4.3.2 Digital Stereo Generator Module, A5
The Digital Stereo Generator Module is the interface between
the AES/EBU audio data standards and the DIGIT™ input
requirements and also includes a fully integrated digital stereo
generator. A block diagram of the board is shown in Figure 4-4.
It accepts one AES/EBU digital stereo audio signal at any
arbitrary data rate between 20.8kHz and 56kHz. It also has inputs
for two analog SCA and one analog RBDS input, as well as an
analog backup input mode (it uses the SCA2 input) which can
be used to bypass a failed digital link. The module outputs
include, one digital composite output, J1 to the Digital Modulator
Board in the exciter, one 19kHz sync output, J8 for RBDS use,
and a simple remote status/control interface, J7. All power and
synchronization signals for the module come from the Digital
Modulator Board in the exciter, via J1.
The stereo generation and processing is accomplished by use of
industry standard general purpose DSP (Digital Signal Processing) devices. The processing maintains greater than 16 bits of
resolution so that round-off and truncation errors fall well below
the 16 bit threshold. The module can be operated in both the
standard stereo and sub channel mode or in Mono mode. The
Mono mode is switchable in real time, both locally and remotely
via J7, and provides a single L+R channel. 100% modulation is
maintained with either a two channel or one channel input.
Action
Press [PA VOLTS] Button
Press [PA AMPS] Button
Press [RFL PWR] Button
Press [FWD PWR] Button
Press [FWD PWR] and [RFL
The Digital Stereo Generator has several key functions:
Press [FWD PWR] and [PA
4.3.2.1 Data Rate Conversion
a.
b.
c.
d.
e.
Data Rate Conversion
Stereo Encoding
SCA and RBDS Injection
Composite Compression (Limiting)
Operational Mode Control
Press [FWD PWR]
and [PA VOLTS] Buttons
Turn on all display lamps and indicators. All other combinations
result in No action.
The Digital Stereo Generator takes the arbitrary data rate of the
received AES/EBU input (between 20.8kHz and 56kHz) and
converts it to a rate compatible with the DIGIT™, Digital Modulator Board input. The conversion is done with a VLSI rate
converter.
4.3.1.2 Power Supply indicators
4.3.2.2 Analog SCA and RBDS Injection
The logo LED is divided into four sections each drawing power
from the four regulated voltages in the exciter. If any dc voltage
fails the corresponding section of the logo LED will be turned
off.
The SCA and RBDS inputs are summed together then digitized
to provide a single digital input for the stereo generator. Full scale
input is 30% injection (in stereo mode, the SCA and RBDS
injection may not exceed 20%). Digital filtering is used to
maintain the stereo SNR level of -80dB.
4.3.2.3 Composite Compression
Adjustment of composite compression level is accomplished in
the digital domain without generating any switching transients
or noticeable noise during adjustment. The limiter uses a proprietary algorithm which achieves higher signal density with much
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Errata: 01-05-95
Section IV - Theory of Operation
lower distortion than conventional composite clipping. The
limiter achieves absolute maximum modulation levels because
it is based on the composite signal rather than the audio. Composite compression is controlled by an externally accessible
multiturn pot. The adjustment provides the means for up to 18dB
of peak limiting relative to:
a. 100% modulation with no SCAs
b. 105% modulation with 1 SCA
c. 110% modulation with 2 SCAs
The adjustment allows 0.1dB of limiting resolution. The composite compression can also be disabled by turning the LIMIT
pot CCW until the deviation level just begins to drop.
4.3.2.4 Analog Backup Mode
The module also has a backup or emergency analog composite
input mode. If the digital signal link is interrupted for some
reason, maybe the loss of the digital STL link, the module may
be placed in the analog backup mode either locally, with a dip
switch setting inside the module, or remotely, via J7 on the side
of the module, by grounding pin 4. An analog composite signal
may then be input in place of the SCA2 signal. More information
is given in the following paragraphs, and in Section III, under the
heading, Emergency Operating Procedures.
4.3.2.5 Operational Mode Control
The Digital Stereo Generator Module provides the user with the
ability to select between various operational modes both locally,
with a dip switch inside the module, S1, and remotely via J7 on
the side of the module. It also allows user control of pilot level,
modulation level, and composite limiting.
4.3.2.5.1
LED Meter
There is an LED meter display on top of the Digital Stereo
Generator Module, see Figure 4-5. This LED meter can be used
to read the amount of Composite Limiting or Percent Deviation.
With switch S1-7, inside the interface module, in the OFF
(normal) position, the LED meter displays the amount of composite limiting in dB. The LEDs then correspond to the labels
1dB, 2dB, 3dB, 4dB and 5dB. The total amount of limiting
available (if the LIMIT pot is turned fully clockwise) is 18dB,
but the display only reads up to 5dB.
The LED meter can be made to read percent deviation if S1-7 is
switched to the ON position. The LEDs in this mode now
correspond to the other set of labels, 100, 105, 110, 120 and
150%, which are deviation levels. In this mode the LED meter
reading and the front panel bargraph display should read approximately the same percent of modulation, or deviation. The Deviation mode on the LED meter can be useful for comparison with
the front panel bargraph display, if the bargraph is suspected to
be faulty. S1-7 should normally be left in the OFF or LIMIT
position since the LED Deviation meter and the front panel
bargraph display read basically the same thing.
The remote I/O connector J7 can also be used to switch the
function of the meter, provided S1-7 is in the open or OFF
position. Leave J7-8 open, and the meter will read the amount of
limiting. Ground J7-8 and the meter will read percent deviation.
4.3.2.5.2
ANALOG (Switch)
• Off: AES/EBU Mode (Default)
• On: Analog Backup Mode (ANALOG status LED is lit
when in Analog mode).
When the ANALOG switch is open (off), the stereo generator is
enabled and the AES/EBU digital input is used to provide the
left and right channel digital audio source. See Figure 4-5.
When the ANALOG switch is closed (on), the stereo generator
is disabled and the SCA2 analog input, J3, will become the
analog composite (program) input. Once the unit is in the analog
backup mode, it is necessary for the operator to remove the
normal SCA2 signal source from J3, and connect the backup
composite input signal.
DO NOT apply the analog backup signal to the SCA2 input, J3,
until the unit has been switched into the analog backup mode. If
the analog backup signal is applied to the SCA2 input before the
Figure 4-4. Block Diagram Digital Stereo Generator
Module, A5
Errata: 01-05-95
888-2333-001
WARNING: Disconnect primary power prior to servicing.
4-5
DIGIT™
unit is switched to the backup mode, overdeviation and interference could occur.
This mode is designed to be a backup operational mode, allowing
a convenient way to bypass a failed digital link. This mode can
also be used to allow the use of analog inputs until such time as
the station installs a full digital link to the transmitter site. A
3.5Vpp (nominal for 75kHz deviation) analog composite signal
should be applied to SCA2 as the backup signal. Other
SCA/RBDS inputs will have to be reduced in amplitude by 16dB
because of the increased gain required to accommodate the
analog composite input. It is also important to note that only the
SCA2 input provide the necessary bandwidth for the analog
composite signal. SCA1 and the RBDS inputs both have high
pass filters that limit low frequency response. The performance
of this mode is degraded from the published spec (S/N = 84dB,
THD = 0.008% typical).
• On: Monaural Mode (MONO status LED is lit when in
Mono mode).
When the MONO switch is open (off), the stereo generator
operates in stereo mode. Both the L+R Main channel and a
38kHz double sideband suppressed carrier L-R Sub-Channel are
generated along with the 19khz pilot. Analog SCA/RBDS inputs
are also accommodated.
When the MONO switch is closed (on), the stereo generator
operates in Mono mode. The generator will provide only the L+R
Main channel and pilot. The 38khz Sub-Channel is not provided.
The pilot can be turned off by adjusting the PILOT pot all the
way counter-clockwise if desired. Because it is assumed that
either the left or right channel is not available in mono mode, an
additional 6dB of gain is provided for the L+R signal. Therefore
if both the left and right channels are to be used, then their
amplitude must be reduced by 6dB.
AES/ANALOG Remote Input J7-4
MONO/STEREO Remote Input, J7-2
The ANALOG mode can be selected remotely via the
AES/ANALOG control input (J7-4) as long as the ANALOG
switch is in the open position (factory setting). When a low
impedance or 0V signal is applied to this input, the Analog mode
is selected. A high impedance or +5V input selects the default
AES/EBU mode. It is recommended that this input be driven by
an open collector source. A TTL/CMOS compatible source is
also acceptable.
The Mono mode can be selected remotely via the MONO/STEREO control input (J7-2) as long as the MONO switch is in the
open or OFF position (factory setting). When a low impedance
or 0V signal is applied to this input, the Mono mode is selected.
A high impedance or +5V input selects the default Stereo mode.
It is recommended that this input be driven by an open collector
source. A TTL/CMOS compatible source is also acceptable.
4.3.2.5.3
MONO (Switch)
• Off: Stereo Mode (Default)
4.3.2.5.4
25uS, 50uS (Switches)
The switches are two sections of DIP switch S1 on the Digital
Stereo Generator board. The 25us and 50us switches can accommodate all of the standard pre-emphasis response adjustments.
Figure 4-5. Digital Stereo Generator Module
LED Meter
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WARNING: Disconnect primary power prior to servicing.
Errata: 01-05-95
Section IV - Theory of Operation
The pre-emphasis is applied in Stereo and Mono modes. For
proper switch setting and switch location refer to Section II
Figure 2-1 and Table 2-1.
4.3.2.5.5
ERR (Switch)
• Off: No repeat on error (Default)
• On: Repeat on error
When the ERR switch is closed (on) the AES/EBU receiver
repeats the last valid data byte if an error occurs. When the error
is removed, the data is transmitted again as normal. When the
ERR switch is open (off) the AES/EBU receiver will not repeat
the last valid byte, but will transmit the data as received regardless of the error. This switch is mostly used as a diagnostic tool.
4.3.2.5.6
WATCHDOG (Switch)
• Off: Watchdog disabled (Default)
• On: Watchdog enabled
When the WATCHDOG switch is open (off) the Watchdog
circuit only monitors the +5V dc voltage. When the WATCHDOG switch is closed (on) the Watchdog circuit monitors the
RBDS Sync output signal as well as the +5V dc voltage. This
provides a way to monitor the DSP function on board for possible
failure modes.
4.3.2.6 Digital Stereo Generator Module User Adjustments
4.3.2.6.1
SCA (Pot Adjustment)
• Clockwise = more gain
The SCA pot (R9) is a gain adjustment for the SCA1, SCA2, and
RBDS analog inputs. The gain adjustment ranges from -6.6dB
to +18.8dB. SCA1 and SCA2 have nominal inputs of 1.5Vpp for
10% (+/- 7.5kHz) deviation. The RBDS input has a nominal
input of 1.5Vpp for 5% (+/-3.75kHz) deviation. When in ANALOG backup mode, SCA2 has a nominal input of 3.5Vpp for
100% (+/-75kHz) deviation.
4.3.2.6.2
DEV (Pot Adjustment)
• Clockwise = more deviation
The DEV pot (R29) is used to set the “ceiling” for the output
deviation level. It tells the stereo generator what the digital stereo
output level should be (does not include SCA inputs) for a full
scale input. For example, with a full scale input signal applied,
the DEV pot would be adjusted to give the desired deviation on
the front panel bargraph meter. The deviation range extends from
95% to 208% (assuming 10% pilot and a full scale digital input)
relative to +/-75kHz deviation. There is also an LED meter on
top of the Digital Stereo Generator Module which can be used to
read deviation instead of the front panel meter. The LED meter
is normally set to read “Limiting” (OFF). The LED meter can be
switched to read deviation by setting S1-7 to the ON position.
The LEDs now correspond to the 100 through 150% labels. The
Deviation mode on the LED meter can also be selected remotely
via J7-8. A high on this input causes the meter to read percent
deviation.
INT DEV LEVEL Remote Output, J7-7
The setting of the DEV pot is available via the INT DEV LEVEL
remote output (J7-7). The output will be between 0V and +5V,
depending on the amount of deviation and exciter input level.
For example, if the audio input level is 0dB, then a 0V output
indicates a 95% deviation setting while a +5V signal represents
a 208% deviation setting (relative to +/-75kHz). The output
deviation setting can be linearly interpolated between 0V and
5V.
4.3.2.6.3
PILOT (Pot Adjustment)
• Clockwise = more deviation
The PILOT pot (R30) is used to set the pilot injection level. The
injection level range extends from 0% to 12% deviation relative
to +/-75kHz deviation.
4.3.2.6.4
EQ (Pot Adjustment)
The EQ pot (R31) is available as a composite equalization
adjustment to compensate for various system (exciter, transmitter, etc.) non-linearities. It is a subtle adjustment that is factory
pre-set depending on the system and customer frequency. The
adjustment affects phase response only.
4.3.2.6.5
LIMIT (Pot Adjustment)
• Clockwise = more limiting
The LIMIT pot (R34) is used to set the amount of composite
limiting. The limiter can accommodate input level ranges between 0dB and -12dB. An additional 12 dB of headroom is
allowed for pre-emphasis. The limiter is psycho-acoustically
designed to provide minimal audible distortion for high levels of
limiting (5dB or greater). The LED meter display on top of the
Figure 4-6. Analog I/O Board Block Diagram
Errata: 01-05-95
888-2333-001
WARNING: Disconnect primary power prior to servicing.
4-7
DIGIT™
Digital Stereo Generator Module is normally set to read the
amount of composite limiting being used, provided S1-7 is in the
OFF (normal) position. The remote input J7-8 must also be low
for the LED meter to be in the LIMIT display mode. The total
amount of limiting available is 18dB, but the display only goes
to 5dB. The limiter has no affect on the pilot or SCAs.
Remote EXT LIMIT LEVEL Input & EXT/INT CONTROL Input:
The LIMIT control can be set remotely via the EXT LIMIT
LEVEL input (J7-6). Local Limit control is overridden and
remote limiting initiated when a low impedance or 0V input is
applied to the EXT/INT CONTROL input (J7-5). When the
EXT/INT CONTROL input is brought low, the limit level is
derived from the dc voltage applied to the EXT LIMIT LEVEL
input. The voltage range of the EXT LIMIT LEVEL input is 0V
to 5V. A higher voltage will provide increased limiting. The
voltage should never exceed +5V.
4.3.2.7 Digital Stereo Generator Module Outputs
4.3.2.7.1
PLL UNLOCK (Output)
PLL status LED is lit when an Unlock condition occurs
A PLL UNLOCK status output is available on the remote output
connector J7-3. Any DSP unlock conditions, or any AES/EBU
communication faults, bring this output high (+5V). For example, a disconnected AES/EBU cable will activate this output.
4.3.2.7.2
RBDS SYNC (Output)
A 19kHz signal is provided for synchronizing the RBDS signal
to the stereo generator. This signal is phase coherent with the
stereo generator pilot. The RBDS sync output is inverted (180o
out of phase) relative to the stereo generator pilot. Filtering of
the RBDS Sync signal may be required. The nearest and largest
alias component is 14dB down at 64.3kHz.
4.3.3 Analog I/O Module
The purpose of the Analog I/O Module is to allow connection of
conventional analog inputs to the digital exciter. This is done by
summing all of the inputs and then converting them into a 16 bit
composite digital format compatible with the digital exciter. A
block diagram of the board is shown in Figure 4-6. The analog
interface is a module that attaches to the back of the DIGIT™
exciter. Composite level and stereo adjustments are accessible
through the top of the analog interface box. If a digital audio input
is desired, this module can be removed and the Digital Stereo
Generator Module used in its place.
4.3.3.1 Analog Inputs (J2 through J7)
The Analog I/O Module provides 6 analog inputs via external
BNC connectors. They are:
1.
2.
3.
4.
5.
6.
4.3.3.1.1
Balanced Composite Input
Unbalanced Composite Input
SCA 1
SCA 2
SCA 3
Monaural input
Balanced Composite (J6)
The Balanced Composite Input is a 10k ohm input impedance.
The nominal input level for 75kHz (100%) deviation is 3.5Vpp.
The Balanced Composite input accommodates a maximum
5Vpp signal without clipping, assuming the Modulation Level
adjustment (R26) is set at the nominal setting of 0dB gain. The
maximum continuous input voltage without damage is 7.5Vpp.
To connect to the balanced inputs (Monaural or Balanced Composite), a special cable must be constructed, with the outer shield
isolated from the connector and terminated in a pigtail which
connects to the ground stud nearby. These cables may be ordered
ready-made in several standard lengths from Harris-Allied, with
Figure 4-7. Digital Modulator Board Block Diagram
4-8
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WARNING: Disconnect primary power prior to servicing.
Errata: 01-05-95
Section IV - Theory of Operation
BNC connectors installed on both ends. Use the following part
numbers when ordering:
922-0014-001
922-0014-002
922-0014-003
922-0014-004
922-0014-005
922-0014-006
4.3.3.1.2
2.5 ft.
5 ft.
10 ft.
15 ft.
25 ft.
40 ft.
Unbalanced Composite (J5)
The Unbalanced Composite Input has a 10k ohm input impedance. The nominal input level for 75kHz (100%) deviation is
3.5Vpp. The input supports a maximum 5Vpp signal without
clipping, assuming the Modulation Level adjustment (R26) is set
at the nominal setting of 0dB gain. The maximum continuous
input voltage without damage is 7.5Vpp.
4.3.3.1.3
SCA1 SCA2 SCA3 (J2, J3, J4).
The three SCA inputs have 10k ohm input impedances. The
nominal input level for 10% (7.5kHz) deviation is 1.5Vpp. The
maximum continuous input voltage without damage is 15Vpp.
4.3.3.1.4
Monaural (J7)
The Monaural Input has a 600 ohm input impedance. The nominal input level for 75kHz deviation at 400Hz is +10dBm into 600
ohms. Input adjustment is provided via R19 and allows inputs to
range between -9.17dBm and 14.4dBm assuming the Modulation Level adjustment (R26) is set at the nominal setting of 0dB
gain. Inputs above 14.4dBm are clipped. The continuous maximum input voltage without damage is 14.5dBm. Pre-emphasis
is provided via jumpers JP1 and JP2 according to table provided
earlier in this section.
4.3.3.2 Data Output Connector (J1)
The 34 pin header, J1, outputs 16 bits (M0, M1, ... M15) of digital
modulation, and receives a 10MHz clock and 500kHz Convert
pulse from the Digital Modulator board. The connector also
supplies power (+17V, -17V, +6.5V, and -6.5V) to the Analog
I/O Module.
4.3.3.2.1
Digital Modulation Output (M0, M1, ... , M15)
The modulation output is a 16 bit parallel format (pin 1 through
pin 16). The data is digital composite stereo with a data rate of
500kHz and coherent with the Convert clock supplied by the
digital modulator board. The data is 2’s complement format with
M0 the LSB and M15 the MSB.
4.3.3.3 Analog I/O Module Power (+17V, -17V, +6.5V, and -6.5V)
J1 also must supply the Analog Interface board with +17V (pin
27), -17V (pin 29), +6.5V (pin 31), and -6.5V (pin 33). Each
voltage is required to be no worse than 5% from nominal voltage.
4.3.4 Digital Modulator Board
A block diagram of the Digital Modulator Board is shown in
Figure 4-7. The Digital Modulator board synthesizes a digital
FM signal using a 32 bit numerically controlled oscillator
(NCO). The NCO requires a digital modulation input (from one
of the interface modules), a frequency tuning number from the
configuration switches and a 20MHz system clock (located on
this board). Manual frequency tuning is achieved by on board
DIP switches. Remote frequency control is also accommodated
Errata: 01-05-95
by an optional remote frequency input connector, J3 on the back
panel, which can be connected to the Digital modulator board
connector J6, for use in N+1 frequency agile systems. The digital
FM signal, from the NCO, is converted to analog by use of a 12
bit Digital to Analog Converter (DAC). The DAC output is an
FM IF signal at approximately 5.6MHz. The exact frequency is
determined by the actual carrier frequency. For more information
on frequency selection refer to Section V, Maintenance and
Alignment. The DAC output is bandpass filtered before final
output to the 5MHz Filter Board.
The Digital Modulator Board also contains a digital peak detector and a serial bargraph driver which drives the front panel
bargraph display (the display is actually located on the Regulator
Board).
4.3.4.1 Data Input connector (J1)
The 34 pin connector J1 accepts 16 bits (M0, M1, ... M15) of
digital modulation (from either the Digital Stereo Generator
Module or the Analog I/O Module), connects various clocks and
control signals for the interface modules, and provides power to
the interface modules (+17V, -17V, +6.5V, and -6.5V).
4.3.4.2 Interface Module Power (+17V, -17V, +6.5V, and -6.5V)
Power is supplied to the interface modules (pins 27, 29, 31, and
33). Each voltage can accommodate at least 500mA of current,
except for the +6.5V pin which can supply 1 amp.
4.3.4.3 Remote Frequency Input (J6 Optional)
J6, a 16 pin ribbon connector accepts a 12 bit TTL/CMOS
compatible frequency tuning word (pins 1 through 12) from J3
on the back panel, for optional remote frequency tuning (only
used for N+1 operation). All J6 connections are shown in the
same general area on sheet 1 of the Digital Modulator schematic.
J6-13 supplies +5V power for external use. Resistor R4 current
limits the output. J6-14 is connected to ground. A remote frequency mute signal is input on J6-15, and J6-16 is not connected.
Changes in the tuning number may be done asynchronously and
the settling time for any tuning changes is required to be less than
400ns to avoid large transitional errors in output frequency. The
tuning algorithm and a Frequency Tuning Chart are provided in
Section V, Maintenance and Alignment.
4.3.4.4 Power Input, Serial Data, and Status (J9)
A 26 pin ribbon connector is used to supply the board with +6.5V
(pins 7 and 9), and -6.5V (pin 5). Other voltages +17V, -17V,
are supplied only for the Digital Stereo Generator Module or the
Analog I/O Module (whichever is installed). The +6.5V input
uses two pins (pin 7 and 9) because of potentially large current
draw. Each voltage is required to be no worse than 5% from
nominal voltage.
4.3.4.5 Serial Bargraph Interface
The front panel bargraph display is driven, via connector J9, by
the following signals:
•
•
•
•
MOD CLOCK (pin 13, 14)
MOD DATA (pin 15, 16)
MOD STROBE (pin 17, 18)
10% SCALE (pin 19, 20)
888-2333-001
WARNING: Disconnect primary power prior to servicing.
4-9
DIGIT™
Figure 4-8. Digital Modulator Switch Settings
4.3.4.9 DAC Test Output (J8)
Each output uses two differential lines consisting of a positive
and negative signal. Data is a serial data stream 32 bits long, each
bit being latched into the parallel bargraph buffer (U9 on the
Regulator Board) by MOD CLOCK, a 1.95kHz clock. The MOD
DATA is a Data word which contains a contiguous number of
“ones” proportional to the modulation level. MOD STROBE is
a pulse that goes high every 61Hz and clocks the 32 bit serial
Data word from the bargraph buffer to the bargraph driver.
A 50 ohm DAC test output is provided to allow sweeping of the
final output filter. It uses an SMB connector and can be connected to a frequency source (with the board out of the exciter)
so that frequency response measurements of the output filter can
be made at the FM output (J7).
4.3.4.10 Adjustments/Settings
4.3.4.10.1
4.3.4.6 NOPGM Fault
Functional Settings (S5)
S5, a four pole switch is used for testing and deviation control,
see Figure 4-8. The first switch (Modulation on/off) turns the FM
modulation on and off. The second switch selects the maximum
deviation level of the exciter. The final two switches are only
used during system set-up and alignment. The table at the bottom
of Figure 4-8 shows each setting.
NOPGM is a TTL compatible output indicating that there is no
digital programming input into the exciter when high. This is for
remote information and can be used as a test point for system
troubleshooting. If the exciter has no digital modulation input (to
the Digital Modulator Board) for at least 4.2 seconds then this
remote output is driven high. The signal will return to a low level
(0 volts) as soon as a digital input is again detected.
The Modulation on/off setting is useful when the exciter center
frequency needs to be measured, or when the carrier level is
desired. A 208% deviation setting provides the user with 108%
(6.38dB) deviation overhead; but with some loss in S/N (2.84dB)
relative to 100% (75kHz) deviation. The recommended setting
is the 150% setting. During normal operation, both Eq A and Eq
B should be in the open position.
4.3.4.7 Remote Frequency Mute Input (N+1 Mute)
For remote frequency control fault protection an exciter RF mute
control is supplied to the Regulator board via J9-12. This input
is received from the optional remote frequency control cable (J6)
which connects the Digital Modulator Board to the optional 25
pin D connector, J3, on the back panel. Further functionality is
discussed in the paragraphs entitled Regulator Board later in this
section.
Note
The input Interface Modules are normally calibrated with Maximum Deviation Level set to 150%. If the Deviation level is then
set to 208%, the modulation level will increase 2.84dB unless the
input level is reduced.
4.3.4.10.2 Frequency Setting Switches (S2, S3, S4)
4.3.4.8 FM Output (J7)
The FM output signal is a 50 ohm output using an SMB connector. The output level is +2dBm (+/-0.5dB) to the 5MHz Filter
Board. In normal operation the output is an FM signal with center
frequency range between 5.55MHz to 5.65MHz. Harmonic and
spurious signals are filtered to levels less than -70dBc.
When the Remote Frequency option is not in use, frequency
selection is accomplished by 12 switches comprising S2, S3, and
S4, see Figure 4-8 and Table 4-1 below. The switches are
Table 4-1. Digital Modulator Board Frequency
Switch Weighting Table (Frequency in Hz)
MSB
N11
102,400
4-10
N10
51,200
S4
N9
25,600
S3
N8
12,800
N7
6400
N6
3200
N5
1600
N4
800
N3
400
888-2333-001
WARNING: Disconnect primary power prior to servicing.
S2
N2
200
N1
100
LSB
N0
50
Errata: 01-05-95
Section IV - Theory of Operation
Table 4-2. PLL Board Coarse Frequency
Switch Weighting Table (Frequency in MHz)
S3
M9
80/40
M8
20
S2
M7
10
M6
5
M5
2.5
M4
1.25
arranged in binary format with the LSB (S2 position D) providing a 50Hz frequency step. Position A of S4 is the MSB. There
is a base offset of 5.5MHz programmed into the frequency
algorithm. Table 4-1 shows the relative weights of each switch.
The Digital Modulator board’s output frequency can then be
found by adding 5.5MHz to the accumulative weights of every
switch. The proper switch settings can be found in the frequency
selection chart at the end of Section V, Maintenance and Alignment.
Note
For more information on how to set the exciter on the proper
frequency, refer to Section V, under the heading Selecting a Frequency.
The Frequency of the Digital Modulator output should be within
15Hz of the desired setting.
4.3.5 5MHz Filter Board
The input to this board is the 5.6MHz FM output from the Digital
modulator Board. The input level is approximately 2dBm. The
5MHz Filter board provides very narrow and relative distortion
free filtering of the 5.6MHz FM IF signal. There is approximately a 10dB signal loss through the filter.
4.3.5.1 Power Connector (J1)
A 10 pin ribbon connector is used to supply the board with +17V
(pin 1), -17V (pin 3), and -6.5V (pin 5). Each voltage is required
to be no worse than 5% from nominal voltage.
4.3.5.2 5MHz Fault
The fault indication is output on J1-9, to the Regulator Board.
This fault is summed in with the Upconverter and 100MHz Filter
S1
M3
1
M2
0.5
M1
0.25
M0
0.125
0
0
Board faults. These are then summed in with the phase locked
loop fault from the PLL Board. Therefore, a fault on any of these
four boards is displayed as a PLL fault on the front panel. For
more information on faults refer to Section VI, Troubleshooting.
4.3.5.3 FM Input (J2)
The FM input is from the Digital Modulator Board. The input
carrier power level must be at least -5dBm. The center frequency
must be 5.6MHz (+/- 1MHz). Harmonics or spurious signals
within 2MHz of any harmonic frequency of the carrier must be
kept below -80dBc. Other spurious components must be no
greater than -40dBc.
4.3.5.4 FM Output (J3)
The FM output is a 50 ohm -9dBm signal (+/- 0.5dB), which is
sent to the Upconverter Board. Harmonics of the fundamental
FM signal should be below -70dBc.
4.3.6 PLL Board
The PLL board serves as a coarse tuning LO for the digital
exciter. A block diagram of the PLL Board is shown in Figure
4-9. It divides the 10MHz TCXO reference oscillator signal to
obtain a 125kHz reference frequency for the phase detector. This
reference frequency serves as the minimum frequency step that
can be obtained by the PLL board. An external low noise VCO
is used to provide the final LO frequency. The VCO input (from
the VCO Board, A6) is sent to a splitter. One output of the splitter
is amplified and routed to the LO (Local Oscillator) output, J5.
This is to become the LO signal for the Upconverter Board. The
second output from the power splitter is divided by a number
determined by the settings of S1, S2 and S3, the Coarse Fre-
Figure 4-9. PLL Board Block Diagram
Errata: 01-05-95
888-2333-001
WARNING: Disconnect primary power prior to servicing.
4-11
DIGIT™
quency Setting Switches. The resulting low frequency is supplied to the phase detector, along with the divided output of the
10Mhz TCXO. The resulting DC phase-error signal is bandwidth-limited and fed to the VCO to lock it to the proper LO
frequency.
4.3.6.1 Coarse Frequency Setting
When the N+1 option is not in use, frequency selection is
accomplished by 12 switches comprised of S1, S2 and S3. When
using N+1, the switches must all be left open. The switches are
weighted as shown in Table 4-3. Note that the MSB selects
80MHz when the switch is open and 40MHz when closed. All
other switches select the given amount below when open and
0Hz when closed. The last two switches are not connected. All
the numbers in Table 4-3 are in MHz. The PLL output frequency
can be found by adding all the weights of the open switches. For
example if switches M9, M6, M5 and M1 were open, the output
frequency would be (80 + 5 + 2.5 + 0.25) MHz = 87.75 MHz.
4.3.6.2 Power Connector (J6)
A 14 pin ribbon connector is used to supply the PLL board with
+17V (pin 1) and -17V (pin 3). Each voltage is required to be no
worse than 5% from nominal voltage.
4.3.6.3 PLL Loss of Lock
The PLL lock indication is output on J6-9. A loss of lock
indication is a low output voltage. The signal requires an external
pull-up resistor on the regulator board to operate properly. This
fault signal is summed in with the fault signals from the Upconverter, 5MHz Filter and 100MHZ Filter Boards. A fault from any
of these boards will cause the front panel PLL fault to light.
4.3.6.4 N+1 connector (J3 Optional)
A 10 pin ribbon connector accepts a 10 bit TTL compatible N+1
input word for optional remote frequency tuning in N+1 installations. Changes in the tuning number may be done asynchronously and the settling time for any tuning changes is required
to be less than 400ns to avoid large transitional errors in output
frequency. The tuning algorithm is given in Section V, under the
heading, Selecting a Frequency.
4.3.6.5 VCO Tuning Voltage (J1)
The VCO tuning voltage controls the frequency of the VCO. The
tuning voltage falls between the range of 4V and 10V for the
normal operating frequency range (82MHz to 102MHz LO
frequency).
4.3.6.6 VCO Input (J2)
This input receives the VCO output at a nominal level of 2.8dBm.
The input must be well padded (6dB nominal) so that no pulling
of the VCO is suffered. This signal is approximately 5.6MHz
below the actual on-channel carrier frequency. This signal is then
buffered and sent to the Upconverter Board as the LO input, and
is also divided down and used as the second input to the phase
detector (the reference 125kHz being the other input).
4.3.6.7 Notch Output (J4)
A notch filter tuning voltage is supplied to the Upconverter board
and is set via the Frequency dip switches on the PLL board.
4.3.6.8 PLL Board Output (J5)
The PLL output is an ac coupled 50 ohm output and is the LO
signal for the Upconverter Board. The level is nominally +4dBm.
The output frequency range of the VCO is from 80MHz to
105MHz.
4.3.6.9 +15V Output to VCO (J7)
All power to the VCO comes from the PLL Board. The VCO
draws about 25mA of +15V which is supplied via connector (J6)
on the PLL board. The voltage is required to be no worse than
5% from nominal voltage.
4.3.6.10 -15V Output to VCO (J8)
The VCO draws about 35mA of -15V which is supplied via
connector (J6) on the PLL board. The voltage is required to be
no worse than 5% from nominal voltage.
Figure 4-10. Block Diagram VCO Board
4-12
888-2333-001
WARNING: Disconnect primary power prior to servicing.
Errata: 01-05-95
Section IV - Theory of Operation
4.3.7 VCO Board
A block diagram of the VCO is shown in Figure 4-10. The VCO
board is a low noise Voltage Controlled Oscillator which inputs
power and a tuning voltage from the PLL board, and outputs an
RF signal to the same PLL board. It is completely enclosed with
a tight RF shielded box. The box is also shock mounted to prevent
microphonic distortion. This board is shipped with stabilizer
screws to prevent shipping damage which must be removed prior
to installation. For more information refer to “Unpacking” in
Section 2, Installation.
4.3.7.1 VCO Output (E1)
The VCO output is connected to a bulk mounted SMB connector
on the VCO box via hook-up wire. The output is a nominal
2.8dBm over the frequency range of 85MHz to 112MHz.
4.3.7.2 VCO Tuning Input (E2)
The VCO Input is connected to a bulk mounted SMB connector
on the VCO box via a 4.99k ohm 1% resistor. The input accepts
any voltage between 0 Volts and 10 Volts, but the normal
operational voltage is 3 Volts to 9 Volts.
4.3.7.3 VCO Power Supply +15V. -15V (E3, E4)
The VCO +/-15 Volt supply inputs are connected to bulk
mounted SMB connectors on the VCO box via hook-up wire.
Each supply is heavily lowpass filtered with an R/C network to
maintain the low noise properties of the VCO.
4.3.8 Upconverter & 100MHz Filter (A4)
The Upconverter and 100MHz Filter are on the same PC board
(A4). The two circuits are kept somewhat separate though, so
that the 100MHz Filter part of the board can be broken away from
the Upconverter and be used as the stand alone 100MHz Filter
Board, A9 (the Upconverter section is discarded). Figure 4-11
shows a simplified drawing of the complete Upconverter Board
and 100MHz Filter Board assembly.
The Upconverter board utilizes a single upconversion to change
the 5.6MHz FM signal to the final FM channel frequency in the
88MHz to 108MHz band. It requires a 5.6MHz FM signal input,
from the 5MHz Filter board, as well as a Local Oscillator (LO)
input, from the PLL board, to perform the necessary upconversion. The output of the Upconverter board contains the on-channel FM carrier as well as all of the various mixing products. The
Upconverter although physically connected to the 100MHz Filter, has no signal connection from its output at J8, to the 100MHz
Filter input at J4. A short coax jumper cable is used to make the
connection. The primary purpose of the 100MHz Filter is to
attenuate the mixing products. The 100MHz Filter output is then
connected to the input of the stand alone 100MHz Filter Board
(A9). The output of this second filter is sent to the 55 watt RF
PA.
4.3.8.1 Power Connector (J2)
A 10 pin ribbon connector, from the Regulator Board, is used to
supply the Upconverter board with +17V (pin 1), -17V (pin 3),
and -6.5V (pin 5). Each voltage is required to be no worse than
5% from these nominal voltages.
4.3.8.2 Upconverter Fault
The Upconverter Fault is output on J2-9 to the Regulator Board.
It is a summary fault of both the Upconverter Board (A4) and the
100MHz Filter board (A9). A the fault signal is a low output to
the Regulator Board. The signal requires an external pull-up
resistor on the Regulator Board to operate properly.
4.3.8.3 Upconverter, J1
Connector J1 on the upconverter board supplies power to J9 on
the stand alone 100MHz Filter board (A9). The voltages include:
J1-1 - (+15V)
J1-3 - (-15V)
J1-7 - (-5.2V)
Figure 4-11. Upconverter & 100MHz Filter
PC Board Configuration
Errata: 01-05-95
888-2333-001
WARNING: Disconnect primary power prior to servicing.
4-13
DIGIT™
4.3.8.4 LO (PLL) Input (J5)
The LO input is driven by the PLL Board output. This is a 50
ohm source having a nominal power level of 4dBm and a
minimum level of 0dBm. The operational frequency for the LO
input must be limited to the 75MHz through 110MHz band.
4.3.8.5 5.6MHz FM Input (J6)
The 5.6MHz FM input is driven by the 5MHz Filter board output.
This is a 50 ohm source having a nominal power level of -8dBm
and a minimum level of -10dBm. The operational frequency for
the LO input must be limited to the 5.5MHz through 5.7MHz
band.
4.3.8.6 Upconverter Output (J8)
The upconverter output requires a coaxial connection to J4 of the
first 100MHz filter in order to allow the removal of the 100MHz
filter part of the board when it is used as a stand alone unit (A9),
see Figure 4-11. The 50 ohm output provides a -2dBm signal in
the frequency range of 87MHz to 108MHz.
4.3.8.7 100MHz Filter Output (J10)
The 100MHz Filter output is really the Upconverter Board
output, since the final output amplifier stage is not used (The
100MHZ Filter output is physically connected, via the PC board,
back to the Upconverter board output J10). The output provides
a -2dB output to the second 100MHz Filter board (A9). The
output frequency range is 87MHz to 108MHz.
4.3.9 100MHz Filter Board, A9
This is the second of the two 100MHz filters, and is identical to
the first one (the one attached to the Upconverter) except for a
few extra parts which are installed on this board that are not
installed on the other. These parts include J9, the power connector and the parts which comprise the RF output amplifier.
4.3.9.1 100MHz Filter Board Power Connector (J9)
When the 100MHz filter portion of the Upconverter board is cut
away, connector J9 is installed to supply power to the stand alone
100MHz Filter board. The 10 pin ribbon connector supplies
+15V (pin 1), -15V (pin 3), and -5.2V (pin 7) to the board from
J1 on the Upconverter.
4.3.9.2 100MHz Filter Output (A9J11)
The output of the second 100MHz filter is a 50 ohm output which
drives the 55 watt RF PA. It provides a +0dBm signal within the
87MHz to 108MHz frequency band.
4.3.10 Regulator Board
The block diagram for the Regulator Board is shown in Figure
4-12. The Regulator board handles the system power distribution
and metering requirements of the exciter. It also controls the
power amplifier (PA), and responds to any fault conditions. The
microcontroller based sense and control architecture allows for
system changes in software and future upgrades.
4.3.10.1 AC Power Supply Input (J1)
The +/-20VAC and +/-10VAC transformer secondary windings
are connected to J1 on the Regulator board. After rectification
and filtering, the 20VAC input must provide a minimum of
18.5V dc at full rated load, and the 10VAC input must provide
a minimum of 8Vdc at full rated load. This assumes that the
appropriate primary tap selection is used for high and low line
voltage. Thermal considerations also require that the rectified
and filtered dc voltage applied to the regulators does not exceed
a voltage which will damage the regulators. These voltages are
given below:
Input
Max
Current
Nominal
Current
Minimum
Voltage
+20VAC
-20VAC
+10VAC
-10VAC
1.0A
0.5A
1.5A
1.0A
850mA
320mA
900mA
850mA
+18.5V
-18V
+8V
-8V
Worst
Case DC
Voltage
+23V
-25V
+10.5V
-12.5V
Figure 4-12. Regulator Board Block Diagram
4-14
888-2333-001
WARNING: Disconnect primary power prior to servicing.
Errata: 01-05-95
Section IV - Theory of Operation
PA Base Voltage Output (J3-12)
4.3.10.2 B+ Supply Input (J2)
4.3.10.3.5
Power for the PA is input on J2, and fused by F1, a 10 amp fuse
on the Regulator Board. The current is also measured on this
board before being applied to the PA. The Voltage is required to
be no less than 23V. If the voltage exceeds 28V, the crowbar
circuit will actuate and blow the fuse (F1). The current is monitored and provided as a metered output. The exciter will begin
power fold-back for currents exceeding 3.88 amps. The maximum current allowed before full foldback occurs is 4.18 amps.
This is used as a fast VSWR response mechanism to protect the
Power Amplifier.
The PA Base Voltage and consequent output power is controlled
by the Regulator Board. This voltage ranges from +B (no output
power) to about 1.4V below +B (maximum output power). At
initial power-on, the controller senses the forward power setting
then ramps the forward power up to the set power level within 1
second.
4.3.10.3 Power Amplifier I/O (J3)
This connector supplies the PA with power (B+) and inputs
various PA status voltages. The forward and reflected power
status voltages are derived from the PA directional coupler. A
voltage relaying PA temperature information is also input for
temperature foldback purposes.
4.3.10.3.1
Forward Power Input (J3-1)
The forward power coupler voltage is sent to the Regulator Board
for front panel and remote metering. Variations and errors in the
forward power coupler voltage can be calibrated out by adjusting
the Forward Power Calibration pot (R56). Refer to Section V,
Maintenance and Alignments, for additional information regarding Forward Power Calibration.
4.3.10.3.2
Reflected Power Input (J3-2)
The reflected power coupler voltage is used to fold back the PA
output power in the case of high VSWR. The exciter is set to
begin foldback for a reflected power coupler voltage of 0.30
Volts. The 0.30V corresponds to approximately 5W reflected
power. If the reflected power exceeds 5 Watts the controller will
reduce PA power to a point where the reflected power is below
5 Watts. The foldback time is between 250 microseconds and
880 microseconds.
4.3.10.3.3
PA Temperature Input (J3-4)
The PA temperature voltage is required to be a linearly increasing
voltage vs. increasing PA temperature. The voltage can be calculated by the following formula. (The voltage accuracy is within
0.03 Volts of nominal at room temperature.)
Temp Input Voltage = 2.98V + (10mV)(PA temperature °C - 25
°C)
The forward power will be folded back until a power level is
reached where a temperature below 80°C (3.53V input) can be
maintained.
4.3.10.3.4
PA Collector Voltage Input (J3-9)
The PA Collector voltage can be measured to within a 1%
accuracy. Normal operational voltages are from 0V to +27V. The
controller is set to fold-back the PA if 27 Volts is exceeded. The
PA power fold-back time is between 205 and 940 microseconds.
If the control foldback fails for any reason then a crow bar circuit
is actuated for voltages exceeding +28V. The crow bar circuit
will short the B+ supply and blow fuse F1 disconnecting B+
power to the PA.
Errata: 01-05-95
4.3.10.4 Front Panel Overlay Connector (J8)
This connector provides four active high button inputs from the
front panel overlay and four active low fault outputs to the front
panel overlay. Another active low output, namely the 10% scale
indicator, is also provided. A key return (J8-5) and two fault
return outputs (J8-11 and J8-12) provide +5V power to the front
panel overlay for button and fault LED operation.
4.3.10.5 Remote Output Connector (J9)
Remote control inputs and exciter status outputs (from J2 on the
back panel) are applied to connector J9 on the Regulator Board.
Status outputs include:
•
•
•
•
•
•
Forward power (FWD PWR)
Reflected power (REF PWR)
PA voltage (PAV)
PA current (PAI)
Exciter fault indication
No program data (NOPGM).
The control inputs are:
•
•
•
•
•
Exciter Mute
Automatic Power Control
Automatic Fault Control interlock common
Automatic Fault Control interlock normally closed contact
Automatic Fault Control interlock normally open contact
4.3.10.5.1
Exciter PA Status (FWD PWR, RFL PWR, PAV, PAI)
These status outputs provide an output voltage which varies
linearly between 0 and +4V as shown earlier in Figure 4-3. For
example if the PA voltage was 16 volts, then 2.0V would be
applied to J9-4. The Remote PA volts and remote PA current are
specified accurate to within 2% at full scale. The Remote Forward Power can be set to within 1% at full scale assuming a
VSWR of 1:1. The curve shown in Figure 4-3a assumes that pot
R55, Remote Forward Power Calibration (accessible from the
top of the exciter) is set all the way clockwise (gain of 1). There
is no accuracy specification for Reflected Power.
4.3.10.5.2
Exciter Fault and No Program Status (Fault, NoPgm)
These status outputs are open collector outputs capable of sinking over 100mA with a pull up resistor to +5 Volts. A high (+5V)
on J9-6 indicates that an exciter fault (PLL unlock, Temperature
fault, or VSWR fault) has occurred. A high (+5V) on J9-13
indicates that there is no digital modulation input to the exciter.
The no program (NoPgm) status is useful in determining input
source faults. If the exciter has no digital modulation input for at
least 4.2 seconds then this remote output is driven high. The
signal will return to 0 volts as soon as a digital input is again
detected.
888-2333-001
WARNING: Disconnect primary power prior to servicing.
4-15
DIGIT™
4.3.10.5.3
Exciter Mute (Mute)
This input should be driven by either a TTL/CMOS compatible
source or an open collector source. The input can be either active
high or active low depending on the position of jumper JP1. The
input voltage is clamped at a maximum of +5V to avoid unpredictable exciter operation and board damage.
4.3.10.5.4
Automatic Power Control (APC)
This input is used to control the exciter power remotely. The
input requires at least a 4V level (into a 10k ohm load) to achieve
an exciter power level of 60W. Higher input voltages are acceptable as long as the APC adjustment pot (R6) is correctly adjusted
to scale the input to the correct voltage. The input is clamped at
a maximum +5V to avoid unpredictable exciter operation and
board damage. The exciter output power will increase linearly
relative to the APC input voltage and is identical to the forward
power curve of Figure 4-3a.
4.3.10.5.5
Automatic Fault Interlock Control (AFC Com, AFC
NC, AFC NO)
18), and 10% SCALE (J4-19, 20) signals from the Digital
Modulator Board. Each input is a differential input. Data is a
serial data stream 32 bits long, each bit being latched into the
parallel bargraph buffer, U9 by MOD CLOCK. The Data word
must be a contiguous number of “ones” proportional to the
modulation level. MOD STROBE is a pulse that goes high every
32 MOD CLOCK cycles, and latches the 32 bit serial Data word
from the bargraph buffer to the bargraph driver. To activate the
10% indicator a low level must be applied to the 10% SCALE
input.
4.3.10.7.1
No Program input (NoPgm)
NoPgm is a single ended TTL compatible input (J4-11) indicating that there is no digital programming input into the exciter
when high. This is for remote information and can be used as a
failure test point for system debugging. It is output as a remote
status signal via J9-13 to the back panel remote connector J2.
4.3.10.7.2
Remote Frequency Mute (N+1 Mute)
A reed relay switch, K1, is provided for the use of the transmitter.
When an exciter fault occurs, the exciter will shut off output
power and switch the relay. The relay will switch a maximum of
0.25 Amps at 100V. The voltage must not exceed 250V, and the
current must not exceed 1A. Use of either the Normally Open or
the Normally Closed contacts is dependent on your system
requirements.
An externally generated Mute signal is supplied on J4-12. This
is only used for N+1 systems. If jumper JP4 is set to the Mute
enable position (pins 2-3), then a high impedance input allows
the input to be pulled high (+5V), and the exciter is muted. This
protects the exciter from faulty remote frequency controllers or
an accidentally disconnected remote cable. If jumper JP4 is set
to the Mute disable position (pins 1-2) then the exciter cannot be
muted by this input. This is the normal or non-N+1 configuration.
4.3.10.6 Power Distribution (J4, J5, J6, J7)
4.3.10.8 PLL Lock Inputs (J5, J6, J7)
The regulator board supplies power to the Digital Modulator,
5MHz Filter, PLL, and Upconverter boards. +17V, -17V, -6.5V
and 6.5V are available using common pin assignments for each
board. The voltages are specified to be within 5% of nominal.
The voltages were chosen to allow on-board regulation to +15V,
-15V, -5.2V, and +5V. This double regulation eliminates the
need for substantial filtering on each board and provides improved noise reduction.
The 5MHz filter, PLL, and Upconverter boards must each supply
fault status on pin 9 of their respective power supply cable back
to the Regulator Board. The 5MHz fault signal produces a fault
for voltages above 0.75V. The PLL Lock and Upconverter fault
signals must provide a TTL low signal when faulted. After a fault
condition occurs the exciter output power is shut down between
65 and 900 microseconds later. The PLL fault light and RF Mute
indicators will also be lit.
4.3.10.7 Digital Modulator Board Interface (J4)
4.3.10.8.1
The front panel bargraph display is driven by the MOD CLOCK
(J4-13, 14), MOD DATA (J4-15, 16), MOD STROBE (J4-17,
Refer to Section V, Maintenance and Alignments for Regulator
Board adjustments and jumper settings.
4-16
Regulator Board Adjustments and Settings
888-2333-001
WARNING: Disconnect primary power prior to servicing.
Errata: 01-05-95
Section V
Maintenance and Alignment
5.1 Preventative Maintenance
DIGIT™ should require little servicing. Extensive digital processing within the exciter eliminates most causes of drift and
ensures stable performance throughout the life of the product. As
with any electronic equipment, reliability of DIGIT™ is enhanced if it is kept clean and cool.
5.5.1 How Frequency is Selected
DIGIT™ uses an advanced method of signal generation and
modulation which permits selection of any frequency within the
exciter’s specification simply by setting a number of switches.
The switches are located on two circuit boards inside the exciter,
the Digital Modulator board and the PLL board.
The PLL board switches (S1, S2 and S3) set the Local Oscillator
(LO) output from the PLL board to the nearest 125 Khz choice,
approximately 5.6 MHz below the desired channel.
5.2 Cleaning
Inspect the intake air fan and the interior of DIGIT™ periodically. Look for dirt deposits, particularly on the PA heatsink,
and clean out any dust or dirt which has collected. If dirt build-up
occurs, consider adding an intake filter to the cooling fan. Accumulated dirt is the enemy of efficient cooling.
During the inspection, check to see if the fan is turning freely and
quietly. Like any moving part, the cooling fan will become worn
after a long period of operation and will need to be replaced.
Doing so before the fan fails will ensure against outage.
The Digital Modulator board switches (S2, S3 and S4) set the
board output frequency to approximately 5.6 MHz. The exact
frequency is chosen to mix with the PLL output to produce the
desired exciter channel.
The correct switch settings to produce any desired output frequency may be found using the following method. Most users
will also find their desired frequency listed along with the
necessary switch settings in the chart at the end of this section.
5.5.2 Digital Modulator Switches
On the Digital Modulator board, S2, S3 and S4 are the frequency
select switches. They are located on the top center of the board
as follows:
5.3 Cooling
Try to do the cleaning and inspection of DIGIT™ as soon as
possible after sign-off and check for elevated temperatures inside. Excessive temperatures are the enemy of reliable operation.
If you note signs of excessive temperature, check to see that the
exciter receives an adequate supply of cooling air and that the
exhaust from the right-hand side can flow away from the exciter
without being blocked.
5.4 Periodic Exciter Alignments
There is no recommended periodic alignment for DIGIT™.
DIGIT™ has been fully aligned and tested at the factory during
manufacture. Very few adjustments should be required subsequently. The following procedures are those you might need
to follow for long term maintenance of DIGIT™.
5.5 Channel Setting and Frequency
Adjustment
When DIGIT™ is first installed, it may need to be set to the
correct operating channel or frequency using dip switches on the
Digital Modulator Board and the PLL Board. Later, as the
reference oscillator crystal ages, the 10 MHz TCXO (Temperature Compensated Crystal Oscillator), on the PLL Board, may
need to be adjusted.
12-01-94
N11
S4
N10
S3
S2
N9 N8 N7 N6 N5 N4 N3 N2 N1 N0
The N0 - N11 designation appears on the metal cover of the
Digital Modulator board. Setting these switches generates a
12-bit binary “word”, or number, with N0 as the low-order bit
and N11 the high-order bit. Setting any one of these switches to
“Open” generates a “1"; closing the switch generates a ”0".
Setting these three switches selects the output frequency of the
Digital Modulator board to a frequency between 5.55 MHz and
5.65 MHz. The exact frequency is 5.5 MHz plus the frequency
steps set by all of the switches which are set to “1". The frequency
weighting of the switches is:
N11
N10
N9
N8
N7
N6
N5
N4
N3
N2
N1
N0
102,400
51,200
25,600
12,800
6400
3200
1600
800
400
200
100
50
Hz
Hz
Hz
Hz
Hz
Hz
Hz
Hz
Hz
Hz
Hz
Hz
888-2333-001
WARNING: Disconnect primary power prior to servicing.
5-1
DIGIT™
5.5.3 PLL Board Switches
On the PLL board, S1, S2 and S3 are the frequency select
switches. They are located near the center of the board as follows:
S3
S2
S1
M9 M8 M7 M6 M5 M4 M3 M2 M1 M0 -
-
The two right-hand sections of S1 are not used.
TheM0 - M9 designation appears on themetalcover ofthePLLboard.
Setting these switches generates a 10-bit binary “word”, or number,
with M0 as the low-order bit and M9 the high-order bit. As with the
Digital Modulator switches, setting any one of these switches to
“Open” generates a “1", closing the switch generates a ”0".
Setting these three switches selects the output frequency of the
PLL board to a frequency between 82.25 MHz and 102.375
MHz. This is the Local Oscillator frequency, which is mixed with
the Digital Modulator board frequency to generate the exciter
output frequency.
The exact frequency is 40 MHz plus the frequency steps set by
all of the switches which are set to “1" or open. The frequency
weighting of the switches is:
M9
M8
M7
M6
M5
M4
M3
M2
M1
M0
80/40
20
10
5
2.5
1.25
1.0
0.5
0.25
0.125
MHz
MHz
MHz
MHz
MHz
MHz
MHz
MHz
MHz
MHz
• Determine the desired frequency. Example: 91.0 MHz.
• Subtract 5.55 MHz from the desired frequency.
91.0 - 5.55 = 85.45 MHz
• Select the Highest frequency possible BELOW this result
by setting the switches on the PLL board.
Result:
5-2
40
40
5
0.25
0.125
———
85.375
quency. To place DIGIT™ on the desired frequency, subtract this LO frequency from the desired frequency:
91.0 - 85.375 = 5.625 MHz
• To place the exciter on 91.0 MHz, we must select the Digital
Modulator switch combination which will place the Digital
Modulator on 5.625 MHz. This will be:
Base Frequency:
N11
Open
N8
Open
N7
Open
N6
Open
N2
Open
5,500,000
102,400
12,800
6400
3200
200
—————
5,625,000
Hz
Hz
Hz
Hz
Hz
Hz
Hz
5.5.5 Frequency Selection Chart
A frequency selection chart is included in this manual, at the end
of this section. It contains the most common frequency choices
and the switch settings needed to set the exciter to those frequencies.
Note
Use of switch settings calculated by any other method is not recommended. Although some desired frequencies may be generated
using more than one combination of switch positions, the settings
listed in the chart or calculated by the method in this section, are
the only choices which will guarantee DIGIT™ operates as
specified.
5.5.6 Setting the TCXO
Once the correct frequency has been selected with the PLL and
Digital Modulator switches, the exciter should be on the correct
frequency. If any minor frequency error exists, the TCXO may
need to be adjusted to place the exciter on the exact desired
frequency.
5.5.4 Selecting a Frequency
Any frequency within the band may be selected, using the
following method:
Base Frequency:
M9 Open
M6 Open
M1 Open
M0 Open
• 85.375 MHz will be our choice for Local Oscillator fre-
MHz
MHz
MHz
MHz
MHz
MHz
5.5.6.1 Test Equipment You Will Need:
An accurately-calibrated frequency counter is necessary. Supply
it with an RF sample of the exciter’s output, making sure the
sample is within the input level range your counter requires. The
sample may be obtained using:
• a suitable attenuator (rated at more than 75 watts), con-
nected to the exciter output.
• an adaptor cable, connected from the 100MHz Filter board
output to the counter (adding attenuator pads if necessary).
The output of this board is approximately +3dBm.
• a suitable RF sample in the transmitter driven by the exciter.
5.5.6.2 Procedure
• Remove modulation from the exciter, by setting Modula-
tion ON/OFF switch S1 on the Digital Modulator board
OFF.
• Measure the exciter output frequency with the frequency
counter.
• The PLL board is in the center of the shelf under the top
cover of the exciter, and the TCXO is located near the upper
left corner of the board. Use a tuning tool to slowly adjust
888-2333-001
WARNING: Disconnect primary power prior to servicing.
12-01-94
Section V - Maintenance and Alignment
the frequency control on the TCXO until the desired frequency is reached. The TCXO control has a range of +/1000 Hz.
If the correct frequency selection has been made using the
switches on the Digital Modulator board and the PLL Board, you
should not have difficulty reaching the required frequency with
the control.
• Restore modulation, with S1 on the Digital Modulator
Board, and return all connections and switches to the normal settings. If correct frequency cannot be achieved, refer
to “How Frequency is Selected” earlier in this section to
verify that the switch setting are correct on the Digital
Modulator and PLL boards
5.6 Exciter Power Level and Power Metering
There are three user setup controls on the Regulator Board. These
are accessible through an opening near the top, right front corner
of the exciter: See Figure 5-1.
• Forward Meter (R56) calibrates the LCD display to accu-
With the exciter output power set to 50 Watts, connect the VOM
to J2-2. Adjust R55, Forward Remote, as needed to produce 3.33
VDC at J2-2 (Maximum output is 4 VDC at 60 watts).
Note
To accommodate HT35 transmitter requirements, set the exciter
output to 8.2 Watts. R55 should be adjusted to provide a 1.34
Volt output for normal HT35 operation.
5.6.4 Exciter APC (R6)
This adjustment is required only if your transmitter or your
system uses the Exciter APC connection, J2-8, to control the
exciter output power. This potentiometer adjusts the APC voltage when external power control is being used. The adjustment
provides only attenuation and cannot increase the APC voltage.
The APC voltage must be greater than 2.5V to achieve 50 Watts
of output power. Adjustment is best performed at the system
level.
• Using the transmitter or a test power supply, connect to J2-8
the DC voltage which is to cause the exciter output to be 50
Watts. Adjust R6, Exciter APC, until the exciter output is
50 watts, as read on the front panel display.
rately read forward power.
• Forward Remote (R55) calibrates a DC remote forward
power metering voltage for remote-control or remote-metering use.
• Exciter APC (R6) is a calibrate control to adjust the sensitivity of the input used by external equipment to vary the
exciter output power.
5.6.1 Test Equipment Setup
To make these adjustments you will need a 100 watt load for the
exciter, and an accurate power measuring device to measure the
exciter’s output. Connect the load and the power measuring
device to the exciter output. You will also need an accurate VOM
to adjust the Forward Remote output.
5.7 Analog I/O Module Adjustments
The following adjustments are factory calibrations which should
not be required during installation.
5.7.1 Input Signal Level Calibration
As supplied, the Analog I/O Module is adjusted to produce 100%
modulation with either of the following:
• A 400 Hz 3.5V P-P sine-wave at the Unbalanced Compos-
ite input.
• A 400 Hz +10 dBm sine-wave at the Monaural (600 ohm)
input.
5.6.2 Forward Meter
Adjust the exciter output power to 50 Watts as read on an external
power meter. Select FWD PWR on the LCD display and adjust
R56, Forward Meter, to calibrate the display reading to 50 Watts.
5.7.2 Adjustments
There are two gain adjustments and one offset adjustment in the
optional Analog I/O Module:
5.6.3 Forward Remote
This adjustment is required only if the Remote FWD Meter Drive
connection, J2-2, is used.
• R19, Monaural Level (MONO LEVEL) sets the Monaural
• R26, Modulation Level (MOD LEVEL) sets the overall
gain for all inputs.
gain.
• R35, DC Offset, (NULL) zeros the exciter modulation
output with no signal input.
Note
The DELAY and AMPL adjustments in this module are factoryset for best exciter operation and should not need to be adjusted
in the field.
5.7.2.1 Equipment Required
An audio test-tone generator with accurate output level metering
is the only test equipment required. The generator should be able
to supply each of the following outputs:
Figure 5-1. Exciter Front Panel & Forward Power
Calibration & Adjustment Pot Position
12-01-94
• 400 Hz Sinewave, 3.5 V P-P, 25 ohms
• 400 Hz Sinewave, +10 dBm, 600 ohms
888-2333-001
WARNING: Disconnect primary power prior to servicing.
5-3
DIGIT™
5.7.2.2 Setting Modulation Level
The input to the Analog I/O Module is basically fixed at a
nominal 3.5Vp-p (at 400Hz) input to either the Unbalanced or
Balanced composite inputs. The nominal line level input to the
exciter should be adjusted, previous to the exciter, to give 100%
modulation at the 3.5Vp-p input level. This will also set the SCA
inputs to give 10% injection (7.5kHz deviation) with a nominal
1.5Vp-p input.
• Use Digital Modulator Board switch, S5 to turn Maximum
Deviation to the 150% position. See Figure 2-3, in Section
2.
• Set the test-tone generator for unbalanced output, 3.5 V P-P,
400 Hz, and connect to the Unbalanced Composite input
(J5).
• Adjust MOD LEVEL (R26) until the exciter front panel
modulation meter indicates less than 100%; then increase
R26 slowly until the 100% indicator just lights.
5.7.2.3 Setting Monaural Level
• Set the test-tone generator for balanced output, 600 ohms,
+10 dBm, 400 Hz, and connect to the Monaural input.
• Adjust MONO LEVEL (R19) until the exciter front-panel
modulation meter indicates less than 100%; then increase
R19 slowly until the 100% indicator just lights.
5-4
This procedure has calibrated the exciter to produce 100% modulation with either 3.5 V. P-P at the Composite input, or +10 dBm
at the Monaural input, with the Max. Deviation switch S5 set to
150% (112.5kHz max. deviation). Some users may choose to
select the 208% deviation setting, which allows deviation up to
a maximum of 156kHz. Changing from 150% to 208% maximum deviation increases exciter headroom by 2.84 dB and may
reduce S/N by 2.84 dB. Selecting 208% also increases the overall
gain 2.84 dB, causing 100% modulation to occur at 2.52 V P-P
composite, or +7.16 dBm from a 400 Hz source.
DIGIT™ can be readjusted to standard input sensitivity after
selecting the 208% deviation setting by following the adjustment
sequences above, Setting Modulation Level and Setting Monaural Level.
5.8 Digital Stereo Generator Module
Adjustments
All adjustments are usually done during the initial installation of
the exciter and may be found in Section 2, Installation.
888-2333-001
WARNING: Disconnect primary power prior to servicing.
12-01-94
Section VI
Troubleshooting
6.1 Faults
The DIGIT™ front panel provides several indicators which can
alert you to problems in the unit:
RF MUTE indicates the output of the exciter has been muted by
an external signal from the Remote Control connector or the N+1
Connector.
• Check external connections to J2-9 and J3-15, on the back
panel of the exciter, to identify the source of the MUTE
command.
6.1.1 SWR
SWR indicates an excessive amount of reflected power at the
output of the exciter. When reflected power exceeds 5 watts, the
SWR light comes on and the exciter reduces it’s output power
level until the reflected level falls below 5 watts.
is lit, sensitivity of the bargraph scale is increased ten times to
permit you to monitor low-level modulation. As long as the /10
indicator remains lit, the first red LED indicator represent 10%.
6.2 RF Output Foldback
Foldback control in the Regulator board is used to protect the PA
against damage due to excess reflected power at the output,
excessive heatsink temperature and excessive DC current. Foldback automatically reduces the output power if necessary to keep
the PA from exceeding these limits:
• Reflected power at the output of 5 watts.
• PA heat sink temperature of 80 degrees C.
• PA current of 4.0 Amperes.
• Check the output cable and the match to the input of the
transmitter.
6.1.2 TEMPERATURE
TEMPERATURE indicates the presence of too high a temperature in the PA circuit. When the PA heatsink temperature reaches
80oC, the TEMPERATURE light turns on and the exciter begins
to lower it’s output power to attempt to bring the temperature
back below 80.
• Check to see that the exciter and transmitter cooling blow-
ers are operating properly, that there is no blockage to the
airstream and that transmitter is receiving an adequate
supply of cool air.
6.1.3 PLL
PLL indicates a problem with the PLL Board (the phase locked
loop has come unlocked), or that a fault has occurred on the
Upconverter, 5MHz Filter or 100MHz Filter Boards. The exciter
mutes if this indicator is lit. The four possible causes of a PLL
indication:
• 5 Mhz Filter Board fault: This is an operational fault which
is signalled by a voltage greater than 0.75 V on J1-9 of the
5 Mhz Filter Board (or J5-9 on the Regulator board).
• PLL Board not locked: This fault means the phase locked
loop has come unlocked and is signalled by a LOW on J6-9
of the PLL board (or J6-9 on the Regulator board).
• Upconverter board or 100 Mhz Filter board fault: This is
an operational fault which is signalled by a LOW on J2-9
of Upconverter board (or J7-9 on the Regulator board). The
faults from these two boards are summed together on the
Upconverter Board. To identify whether the Upconverter,
A4 or the 100 Mhz Filter, A9 is the cause, temporarily
remove JP7 on the Upconverter to disconnect the Upconverter fault signal. BE SURE TO REPLACE THIS
JUMPER!
6.1.4 PERCENT MODULATION /10
PERCENT MODULATION /10 means no modulation reaching
15%, which might signal a loss of input. When the /10 indicator
12-01-94
6.3 Fuses
There are two fuses included in DIGIT™. Fuse F1 in the rearpanel power input connector protects the whole exciter against
excess current input and possible damage. The size of this fuse
is determined by the operating voltage. See Section II, Installation, for more information.
Fuse F1 on the Regulator Board is a 10-ampere, 32 volt fuse,
used to protect the PA module. This fuse will open if current flow
into the PA power circuits exceeds 10 amperes, several times the
normal value. A crowbar circuit is also included in this DC path,
set to trip if the PA DC voltage reaches 30 Vdc. The crowbar
causes fuse F1 to blow, protecting the PA against potentially
damaging excess voltage.
CAUTION
Regulator board fuse F1 should NOT be replaced with a value
larger than 10 Amperes or with a SlowBlow fuse.
6.4 DC Power Indicators
The DIGIT™ logo indicator in the upper right corner of the front
panel is lit by 4 LED’s which also serve as power supply
indicators. If any segment is dark, the associated power supply
output is low or non-existent. From Left to Right, the 4 indicators
signal the following power supplies:
+17V
-17V
+6.5V
-6.5V
6.5 Remote Indicators
Two remote status indications are available at J2 and may be
monitored manually or by remote control equipment:
888-2333-001
WARNING: Disconnect primary power prior to servicing.
6-1
DIGIT™
6.5.1 Remote FAULT
Remote FAULT (J2-6) is a summary fault which alarms in the
event of PLL Unlock, Temperature Fault or VSWR Fault occurs.
Jumper JP3 on the Regulator board may be used to designate
whether a LOW or HIGH signals the fault condition.
• Check DIGIT™ front panel to identify source of the fault.
6.5.2 NOPGM
NOPGM (J2-13) indicates there is no digital modulating signal
reaching the modulator board. NOPGM is signalled by a HIGH
(Open), appearing on J2-13, 4.2 seconds after loss of digital data
at the input. The HIGH condition remains until input resumes.
6.7 Troubleshooting Flow Charts
The following flow charts are provided for troubleshooting the
exciter down to the individual board level. Due to the complex
circuitry and the surface mount technology used in the exciter,
customer repair of individual boards is not recommended, but
rather that the whole board be replaced with either a spare board
or an exchange board from Harris. For more information on
repair and board exchange please feel free to call the Harris
Allied parts department representative.
• Check the signal path to the input of DIGIT™ to identify
the source of the outage.
6.6 Signal Tracing
Although the digital data within the Digital Modulator does not
lend itself to easy signal-tracing methods, the IF, Local Oscillator
and on-channel FM signals in DIGIT™ may be traced and
checked with a spectrum analyzer or other RF measuring device.
Given in Figure 6-1 and below in Table 6-1, is the amplitude and
frequency of the signal to be expected at several key points in the
IF and RF chain.
6.6.1 Approximate RF and IF Frequencies
For the exact frequencies of the IF and LO signals refer to Section
V, under the heading “How to Select Frequency.”
IF =
LO =
RF =
Intermediate Frequency
Local Oscillator signal
On-Channel RF signal
5.6 MHz (approx)
82 to 102 MHz
88 to 108 MHz
Table 6-1. Troubleshooting Check Points
Board
Digital Modulator A3-J7 (Output)
5 MHz Filter A8-J3 (Output)
PLL Board A7-J5 (LO Output)
Upconverter A4-J8 (U/C Output)
Upconverter A4-J10 (Output)
100 MHz Filter Board A9-J11 (Output)
DIGIT™ J1 (PA output, RF Output)
6-2
Signal Level in dBm
+ 2.0 dBm
- 9.0 dBm
+ 2.9 dBm
- 2.0 dBm
- 2.0 dBm
+10.0 dBm
55 Watts max.
Type of Signal
IF
IF
LO
RF
RF
RF
RF
888-2333-001
WARNING: Disconnect primary power prior to servicing.
Approximate Frequency
5.6 MHz
5.6 MHz
82-102 MHz
88-108 MHz
88-108 MHz
88-108 MHz
88-108 MHz
12-01-94
Section VI - Servicing
Figure 6-1. Troubleshooting Checkpoints
12-01-94
888-2333-001
WARNING: Disconnect primary power prior to servicing.
6-3
DIGIT™
6-4
888-2333-001
WARNING: Disconnect primary power prior to servicing.
12-01-94
Section VI - Servicing
12-01-94
888-2333-001
WARNING: Disconnect primary power prior to servicing.
6-5
DIGIT™
6-6
888-2333-001
WARNING: Disconnect primary power prior to servicing.
12-01-94
Section VI - Servicing
12-01-94
888-2333-001
WARNING: Disconnect primary power prior to servicing.
6-7
DIGIT™
6-8
888-2333-001
WARNING: Disconnect primary power prior to servicing.
12-01-94
Section VI - Servicing
12-01-94
888-2333-001
WARNING: Disconnect primary power prior to servicing.
6-9
Section VII
Parts List
Replaceable Parts List
Table 7-1.
Table 7-2.
Table 7-3.
Table 7-4.
DIGIT EXCITER ANALOG I/O DIGIT EXCITER DIGITAL I/O BASIC, DIGIT FM EXCITER REGULATOR BD ASSY -
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. 994 9410 001
. 994 9410 003
. 994 9410 002
. 992 8674 001
7-1
7-2
7-3
7-4
Table 7-1. DIGIT EXCITER ANALOG I/O - 994 9410 001
HARRIS P/N
DESCRIPTION
QTY/UM
000 0000 010 . . . . . B/M NOTE: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0
990 1130 001
990 1132 001
992 8901 001
992 8902 001
992 8941 001
992 8990 001
992 8991 001
992 8992 001
992 8993 001
992 8994 001
992 8995 001
992 8996 001
992 8997 001
992 8998 001
992 9248 001
994 9410 002
994 9425 001
994 9478 001
994 9506 001
994 9515 001
994 9516 001
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
*R-SC/FUSE KIT,AI DIGIT01 . . . . . . . . . . . . . . .
*C-SC/FUSE KIT,AI DIGIT02 . . . . . . . . . . . . . . .
KIT, PT MOUNTING (OPTION). . . . . . . . . . . . . .
KIT, RACK MOUNTING . . . . . . . . . . . . . . . . . . .
KIT, REMOTE ADAPTER CABLE. . . . . . . . . . . .
KIT, HT250/500/1 XMTR MTG . . . . . . . . . . . . . .
KIT,HT3.5/5/7/10 XMTR MTG . . . . . . . . . . . . . . .
KIT, HT20/HT25 XMTR MTG . . . . . . . . . . . . . . .
KIT, HT30/35 XMTR MTG . . . . . . . . . . . . . . . . .
KIT, PT2/5/8/10 RACK MTG . . . . . . . . . . . . . . .
KIT, HT250/500/1 RACK MTG . . . . . . . . . . . . . .
KIT,HT3.5/5/7/10 RACK MTG . . . . . . . . . . . . . . .
KIT, HT20/25 RACK MTG . . . . . . . . . . . . . . . . .
KIT, HT30/35 RACK MTG . . . . . . . . . . . . . . . . .
KIT, 15 PIN D CONNECTOR . . . . . . . . . . . . . . .
BASIC, DIGIT FM EXCITER . . . . . . . . . . . . . . .
MODULE, ANALOG I/O . . . . . . . . . . . . . . . . . . .
KIT, REMOTE FREQ CONTROL . . . . . . . . . . . .
KIT, DIGIT XMTR ACCYS . . . . . . . . . . . . . . . . .
* R-SP KIT, DIGIT EXCITER. . . . . . . . . . . . . . . .
* R-SB KIT, AI DIGIT . . . . . . . . . . . . . . . . . . . . .
Rev. E: 09-19-95
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
0
0
0
0
REF. SYMBOLS/EXPLANATIONS
THE TAG ON THE REAR OF THIS UNIT TO BE MARKED
WITH THE VOLTAGE THAT THE DIGIT IS CONFIGURED
XMTR MTG OPTION
RACK MTG OPTION
(OPTION)
XMTR MOUNT OPTION
XMTR MOUNT OPTION
XMTR MOUNT OPTION
XMTR MOUNT OPTION
RACK MOUNT
RACK MOUNT
RACK MOUNT
RACK MOUNT
RACK MOUNT
A005
(OPTION)
(OPTION)
888-2333-001
WARNING: Disconnect primary power prior to servicing.
7-1
DIGIT™
Table 7-2. DIGIT EXCITER DIGITAL I/O - 994 9410 003
HARRIS P/N
DESCRIPTION
QTY/UM
000 0000 010. . . . . . B/M NOTE: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0
990 1133 001. . . . . .
990 1134 001. . . . . .
992 8901 001. . . . . .
992 8902 001. . . . . .
992 8941 001. . . . . .
992 8990 001. . . . . .
992 8991 001. . . . . .
992 8992 001. . . . . .
992 8993 001. . . . . .
992 8994 001. . . . . .
992 8995 001. . . . . .
992 8996 001. . . . . .
992 8997 001. . . . . .
992 8998 001. . . . . .
992 9248 001. . . . . .
994 9410 002. . . . . .
994 9478 001. . . . . .
994 9506 001. . . . . .
994 9515 001. . . . . .
994 9530 001. . . . . .
994 9543 001. . . . . .
7-2
*R-SC/FUSE KIT,DI DIGIT03 . . . . . . . . . . . . . . . .
*C-SC/FUSE KIT,DI DIGIT04 . . . . . . . . . . . . . . . .
KIT, PT MOUNTING (OPTION) . . . . . . . . . . . . . .
KIT, RACK MOUNTING . . . . . . . . . . . . . . . . . . .
KIT, REMOTE ADAPTER CABLE . . . . . . . . . . . .
KIT, HT250/500/1 XMTR MTG. . . . . . . . . . . . . . .
KIT,HT3.5/5/7/10 XMTR MTG . . . . . . . . . . . . . . .
KIT, HT20/HT25 XMTR MTG . . . . . . . . . . . . . . .
KIT, HT30/35 XMTR MTG . . . . . . . . . . . . . . . . . .
KIT, PT2/5/8/10 RACK MTG . . . . . . . . . . . . . . . .
KIT, HT250/500/1 RACK MTG . . . . . . . . . . . . . . .
KIT,HT3.5/5/7/10 RACK MTG . . . . . . . . . . . . . . .
KIT, HT20/25 RACK MTG . . . . . . . . . . . . . . . . . .
KIT, HT30/35 RACK MTG . . . . . . . . . . . . . . . . . .
KIT, 15 PIN D CONNECTOR . . . . . . . . . . . . . . .
BASIC, DIGIT FM EXCITER . . . . . . . . . . . . . . . .
KIT, REMOTE FREQ CONTROL . . . . . . . . . . . .
KIT, DIGIT XMTR ACCYS . . . . . . . . . . . . . . . . . .
* R-SP KIT, DIGIT EXCITER . . . . . . . . . . . . . . . .
DIGITAL STEREO . . . . . . . . . . . . . . . . . . . . . . . .
* R-SB KIT, DI DIGIT . . . . . . . . . . . . . . . . . . . . . .
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
0
0
0
1
0
REF. SYMBOLS/EXPLANATIONS
THE TAG ON THE REAR OF THIS UNIT TO BE MARKED
WITH THE VOLTAGE THAT THE DIGIT IS CONFIGURED
XMTR MTG OPTION
RACK MTG OPTION
(OPTION)
XMTR MOUNT OPTION
XMTR MOUNT OPTION
XMTR MOUNT OPTION
XMTR MOUNT OPTION
RACK MOUNT
RACK MOUNT
RACK MOUNT
RACK MOUNT
RACK MOUNT
(OPTION)
(OPTION)
A005
888-2333-001
WARNING: Disconnect primary power prior to servicing.
Rev. E: 09-19-95
Table 7-3. BASIC, DIGIT FM EXCITER - 994 9410 002
HARRIS P/N
250 0274 000 . . . . .
302 0733 000 . . . . .
358 0834 000 . . . . .
358 1214 000 . . . . .
358 3197 000 . . . . .
358 3424 000 . . . . .
384 0702 000 . . . . .
398 0087 000 . . . . .
398 0090 000 . . . . .
402 0020 000 . . . . .
424 0002 000 . . . . .
424 0004 000 . . . . .
426 0079 000 . . . . .
430 0030 000 . . . . .
430 0192 000 . . . . .
472 1689 000 . . . . .
484 0420 000 . . . . .
610 1136 000 . . . . .
646 0569 000 . . . . .
646 0665 000 . . . . .
646 1250 000 . . . . .
646 1253 201 . . . . .
817 2335 003 . . . . .
843 5295 001 . . . . .
843 5295 022 . . . . .
843 5295 041 . . . . .
843 5295 072 . . . . .
917 2106 001 . . . . .
922 1205 023 . . . . .
922 1205 030 . . . . .
939 8120 022 . . . . .
939 8120 023 . . . . .
939 8120 024 . . . . .
939 8120 034 . . . . .
939 8120 040 . . . . .
943 5295 023 . . . . .
943 5295 044 . . . . .
943 5295 050 . . . . .
943 5295 051 . . . . .
943 5295 052 . . . . .
943 5295 053 . . . . .
943 5295 054 . . . . .
943 5295 057 . . . . .
943 5295 060 . . . . .
943 5295 061 . . . . .
988 2333 001 . . . . .
992 8673 001 . . . . .
992 8674 001 . . . . .
992 8676 001 . . . . .
992 8679 001 . . . . .
992 8680 001 . . . . .
992 8681 001 . . . . .
992 8707 001 . . . . .
DESCRIPTION
QTY/UM
CORD, POWER 3C 7-1/2 FT . . . . . . . . . . . . . . . 1
SCR 10-32 X 2-1/2 . . . . . . . . . . . . . . . . . . . . . . . 1
RF STRIP 813-9363-001 . . . . . . . . . . . . . . . . . . .9 FT
SCREWLOCK, FEMALE . . . . . . . . . . . . . . . . . . 1
SLIDES 10" PAIR . . . . . . . . . . . . . . . . . . . . . . . . 1 PR
PLUG, 25 PIN D BLACK . . . . . . . . . . . . . . . . . . . 1
RECT FW BRIDGE 600V 35A . . . . . . . . . . . . . . 1
FUSE, SLOW CART 5A 125V . . . . . . . . . . . . . . 1
FUSE, SLOW CART 3A 250V . . . . . . . . . . . . . . 1
CLIP, FUSE . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
GROMMET 7/16 MTG DIA . . . . . . . . . . . . . . . . . 1
GROMMET 5/8 MTG DIA . . . . . . . . . . . . . . . . . . 1
ISOLATOR, BALL MOUNT . . . . . . . . . . . . . . . . . 4
*FAN 115VAC 106CFM 4.69SQ . . . . . . . . . . . . . 1
GUARD, FINGER/FAN . . . . . . . . . . . . . . . . . . . . 2
XFMR, POWER, TOROID . . . . . . . . . . . . . . . . . 1
FILTER, RFI POWER ENTRY . . . . . . . . . . . . . . 1
ADAPTOR, EMI FILTERED . . . . . . . . . . . . . . . . 1
LABEL 814-2939-001 . . . . . . . . . . . . . . . . . . . . . 1
INSPECTION LABEL . . . . . . . . . . . . . . . . . . . . . 1
LABEL H-136 . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
LABEL, WARNING . . . . . . . . . . . . . . . . . . . . . . . 1
FREQUENCY CHART, DIGIT . . . . . . . . . . . . . . 0
INTERCONNECT DIAGRAM . . . . . . . . . . . . . . . 0
FAMILY TREE, FM EXCITER . . . . . . . . . . . . . . 0
OVERLAY, FRONT PANEL . . . . . . . . . . . . . . . . 1
WIRING DIAGRAM, . . . . . . . . . . . . . . . . . . . . . . 0
TAG, INPUT AC VOLTAGE . . . . . . . . . . . . . . . . 1
COVER, AC ENTRY . . . . . . . . . . . . . . . . . . . . . . 1
COVER, SHIELD . . . . . . . . . . . . . . . . . . . . . . . . 1
HINGE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
COVER XFMR . . . . . . . . . . . . . . . . . . . . . . . . . . 1
COVER, DIGITAL MOD BD. . . . . . . . . . . . . . . . . 1
DIVIDER SHIELD . . . . . . . . . . . . . . . . . . . . . . . . 1
SHIELD, VCO . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
CHASSIS, MAIN . . . . . . . . . . . . . . . . . . . . . . . . . 1
PANEL ASSEMBLY, FRONT . . . . . . . . . . . . . . . 1
COVER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
COVER, 5 MHZ FILTER . . . . . . . . . . . . . . . . . . . 1
COVER, 100 MHZ FILTER . . . . . . . . . . . . . . . . . 1
COVER, UPCONVERTER . . . . . . . . . . . . . . . . . 1
COVER, PLL . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
DIVIDER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
DISCRETE WIRE CABLE PKG . . . . . . . . . . . . . 1
RIBBON CABLE PKG . . . . . . . . . . . . . . . . . . . . 1
DP, DIGIT INSTAL & OPER . . . . . . . . . . . . . . . . 1
DIGITAL MODULATOR BD . . . . . . . . . . . . . . . . 1
REGULATOR BD ASSY . . . . . . . . . . . . . . . . . . . 1
PLL BOARD ASSY . . . . . . . . . . . . . . . . . . . . . . . 1
RF PA MODULE . . . . . . . . . . . . . . . . . . . . . . . . . 1
FILTER 5 MHZ . . . . . . . . . . . . . . . . . . . . . . . . . . 1
FILTER 100MHZ . . . . . . . . . . . . . . . . . . . . . . . . . 1
UPCONVERTER BOARD . . . . . . . . . . . . . . . . . 1
Rev. E: 09-19-95
REF. SYMBOLS/EXPLANATIONS
#T001
#J002
#J003
CR001
F001 #110V
F001 #220V
#F001
#FAN
#XFMR
#A006
B001
#B001
T001
FL001
J002
#AC
#SIDE
#TOP
#TOP
THIS TAG TO BE ATTACHED TO THE REAR PANEL
A003
A002
A007
A001
A008
A009
A004
888-2333-001
WARNING: Disconnect primary power prior to servicing.
7-3
DIGIT™
992 8906 001. . . . . . MODULE, VCO . . . . . . . . . . . . . . . . . . . . . . . . . . 1
999 2759 001. . . . . . HARDWARE LIST, BASIC, DIG. . . . . . . . . . . . . . 1
A006
Table 7-4. REGULATOR BD ASSY - 992 8674 001
HARRIS P/N
354 0309 000. . . . . .
358 2997 000. . . . . .
380 0125 000. . . . . .
382 0522 000. . . . . .
382 0719 000. . . . . .
382 0905 000. . . . . .
382 1043 000. . . . . .
382 1126 000. . . . . .
382 1148 000. . . . . .
382 1321 000. . . . . .
382 1323 000. . . . . .
382 1325 000. . . . . .
382 1326 000. . . . . .
382 1327 000. . . . . .
382 1328 000. . . . . .
382 1329 000. . . . . .
382 1330 000. . . . . .
382 1355 000. . . . . .
382 1356 000. . . . . .
382 1369 000. . . . . .
382 1418 000. . . . . .
382 1436 000. . . . . .
384 0205 000. . . . . .
384 0321 000. . . . . .
384 0665 000. . . . . .
384 0737 000. . . . . .
384 0827 000. . . . . .
384 0838 000. . . . . .
384 0847 000. . . . . .
384 0893 000. . . . . .
386 0112 000. . . . . .
386 0154 000. . . . . .
398 0031 000. . . . . .
402 0129 000. . . . . .
404 0513 000. . . . . .
404 0673 000. . . . . .
404 0674 000. . . . . .
404 0675 000. . . . . .
404 0747 000. . . . . .
404 0766 000. . . . . .
404 0767 000. . . . . .
404 0827 000. . . . . .
404 0830 000. . . . . .
404 0842 000. . . . . .
404 0851 000. . . . . .
406 0511 000. . . . . .
444 2986 000. . . . . .
516 0453 000. . . . . .
7-4
DESCRIPTION
QTY/UM
TERM SOLDER . . . . . . . . . . . . . . . . . . . . . . . . . 13
END PLATE,236 TERM MODULE . . . . . . . . . . . . 1
XSTR, NPN 2N4401 . . . . . . . . . . . . . . . . . . . . . . 1
IC, LM393N . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
IC LM324AN ESD . . . . . . . . . . . . . . . . . . . . . . . . 2
IC, 78L08/78L82 . . . . . . . . . . . . . . . . . . . . . . . . . 1
IC UDN2595 ESD . . . . . . . . . . . . . . . . . . . . . . . . 1
IC 78L12A ESD . . . . . . . . . . . . . . . . . . . . . . . . . . 1
IC 75173 (ESD) . . . . . . . . . . . . . . . . . . . . . . . . . . 1
IC LM2940CT-5 ESD . . . . . . . . . . . . . . . . . . . . . . 1
IC, 145453 LCD DRIVER ESD. . . . . . . . . . . . . . . 1
IC UCN5818EPF ESD . . . . . . . . . . . . . . . . . . . . . 1
IC, 528 DAC ESD . . . . . . . . . . . . . . . . . . . . . . . . 1
IC, 145051 A/D CNVRTR ESD. . . . . . . . . . . . . . . 1
IC, 1085 REGULATOR ESD . . . . . . . . . . . . . . . . 1
IC, 1086 REGULATOR ESD . . . . . . . . . . . . . . . . 1
IC, LT1185 ESD . . . . . . . . . . . . . . . . . . . . . . . . . . 1
IC, AD626 DIFF AMP ESD. . . . . . . . . . . . . . . . . . 1
IC, 2991 ADJ VOLT REG ESD. . . . . . . . . . . . . . . 1
IC REF-02CP ESD . . . . . . . . . . . . . . . . . . . . . . . . 1
IC 24C04 CMOS EEPROM ESD . . . . . . . . . . . . . 1
IC, MAX705 WATCHDOG ESD . . . . . . . . . . . . . . 1
DIODE SILICON 1N914/4148 . . . . . . . . . . . . . . . 2
DIODE 5082-2800/1N5711 . . . . . . . . . . . . . . . . . 1
RECT, FW BRIDGE 2A 600V . . . . . . . . . . . . . . . 2
SCR,CROWBAR 50V 750A PEAK. . . . . . . . . . . . 1
LED LIGHT BAR, GREEN . . . . . . . . . . . . . . . . . . 2
TRANSZORB 1N6380 36V 5W . . . . . . . . . . . . . . 2
LED 10 SEG BARGRAPH, GRN . . . . . . . . . . . . . 2
LED 10 SEG BARGRAPH, RED . . . . . . . . . . . . . 1
ZENER, 1N4733 5.1V . . . . . . . . . . . . . . . . . . . . . 1
ZENER, 1N4751A 30V . . . . . . . . . . . . . . . . . . . . 1
FUSE, FAST CART 10A 32V . . . . . . . . . . . . . . . 1
CLIP, 1/4 DIA FUSE . . . . . . . . . . . . . . . . . . . . . . 2
HEAT SINK PA1-1CB . . . . . . . . . . . . . . . . . . . . . 1
SOCKET 8 PIN DIP (DL) . . . . . . . . . . . . . . . . . . . 5
SOCKET 14 PIN DIP (D-L) . . . . . . . . . . . . . . . . . 3
SOCKET IC 16 CONT . . . . . . . . . . . . . . . . . . . . . 1
SOCKET STRIP 16 POS . . . . . . . . . . . . . . . . . . 1
SOCKET 18 PIN DIP (DL) . . . . . . . . . . . . . . . . . . 1
SOCKET 20 PIN DIP (DL) . . . . . . . . . . . . . . . . . . 2
SOCKET, DIP20, LO PROFILE . . . . . . . . . . . . . . 3
SOCKET PLCC-44 . . . . . . . . . . . . . . . . . . . . . . . 3
HEATSINK FOR TO220 . . . . . . . . . . . . . . . . . . . 3
SOCKET, 18 PIN SIP . . . . . . . . . . . . . . . . . . . . . 2
DISPLAY, LCD . . . . . . . . . . . . . . . . . . . . . . . . . . 1
XTAL 4MHZ HC/49 CASE . . . . . . . . . . . . . . . . . . 1
CAP .1UF 100V 20% X7R . . . . . . . . . . . . . . . . . 22
REF. SYMBOLS/EXPLANATIONS
#TB001
Q001
U020
U005 U011
U013
U002
U004
U050
U014
U001
U009
U008
U007
U017
U018
U016
U012
U015
U006
U010
U019
CR001 CR007
CR009
CR003 CR004
Q002
DS001 DS002
CR005 CR006
DS006 DS007
DS005
CR008
CR002
F001
XF001
SKU015
XU006 XU010 XU012 XU019 XU020
XU005 XU011 XK001
XU050
XDS001
XU002
XU007 XU008
XDS005 XDS006 XDS007
XU001 XU003 XU009
SKU016 SKU017 SKU018
XDS004
DS004
Y001
C002 C003 C004 C005 C006 C007
C010 C012 C013 C014 C018 C019
888-2333-001
WARNING: Disconnect primary power prior to servicing.
Rev. E: 09-19-95
Section VII - Parts List
516 0736 000
516 0769 000
516 0792 000
516 0971 000
522 0548 000
522 0570 000
522 0590 000
522 0591 000
522 0592 000
522 0593 000
522 0601 000
540 1375 000
540 1386 000
540 1410 000
540 1416 000
540 1434 000
540 1496 000
542 1593 000
548 2252 000
548 2400 166
548 2400 168
548 2400 173
548 2400 201
548 2400 239
548 2400 251
548 2400 257
548 2400 268
548 2400 273
548 2400 301
548 2400 308
548 2400 313
548 2400 326
548 2400 341
548 2400 343
548 2400 366
548 2400 394
548 2400 401
548 2400 410
548 2400 449
548 2400 460
548 2400 501
548 2400 521
548 2400 601
548 2400 701
550 0967 000
550 0970 000
560 0094 000
574 0496 000
604 1147 000
610 0900 000
610 0979 000
610 0981 000
610 1092 000
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
CAP .001UF 10% 100V X7R . . . . . . . . . . . . . . .
CAP 22PF 5% 100V C0G . . . . . . . . . . . . . . . . . .
CAP NETWORK .1UF 10% . . . . . . . . . . . . . . . .
CAP 470PF 5% 100V C0G . . . . . . . . . . . . . . . . .
CAP 10UF 50V ELECTROLYTIC . . . . . . . . . . . .
CAP 2.2UF 50V . . . . . . . . . . . . . . . . . . . . . . . . .
CAP 470UF 25V 20% . . . . . . . . . . . . . . . . . . . . .
CAP 47UF 25V 20% . . . . . . . . . . . . . . . . . . . . . .
CAP 100UF 20% 25VDC . . . . . . . . . . . . . . . . . .
CAP 3300UF 20% 25VDC . . . . . . . . . . . . . . . . .
CAP 15,000 UF 50V 20% . . . . . . . . . . . . . . . . . .
RES NETWORK 1000 OHM 2% . . . . . . . . . . . .
RES NETWORK 10K OHM 2% . . . . . . . . . . . . .
RES NETWORK 330 OHM 2% . . . . . . . . . . . . .
RES NETWORK 10K OHM 2% . . . . . . . . . . . . .
RES NETWORK 330 OHM 2% . . . . . . . . . . . . .
RES NETWORK 100 OHM . . . . . . . . . . . . . . . . .
RES. 0.2 OHM 1% 4W . . . . . . . . . . . . . . . . . . . .
RES 1K OHM 2W 5% FP . . . . . . . . . . . . . . . . . .
RES 47.5 OHM 1/2W 1% . . . . . . . . . . . . . . . . . .
RES 49.9 OHM 1/2W 1% . . . . . . . . . . . . . . . . . .
RES 56.2 OHM 1/2W 1% . . . . . . . . . . . . . . . . . .
RES 100 OHM 1/2W 1% . . . . . . . . . . . . . . . . . .
RES 249 OHM 1/2W 1% . . . . . . . . . . . . . . . . . .
RES 332 OHM 1/2W 1% . . . . . . . . . . . . . . . . . .
RES 383 OHM 1/2W 1% . . . . . . . . . . . . . . . . . .
RES 499 OHM 1/2W 1% . . . . . . . . . . . . . . . . . .
RES 562 OHM 1/2W 1% . . . . . . . . . . . . . . . . . .
RES 1K OHM 1/2W 1% . . . . . . . . . . . . . . . . . . .
RES 1.18K OHM 1/2W 1% . . . . . . . . . . . . . . . . .
RES 1.33K OHM 1/2W 1% . . . . . . . . . . . . . . . . .
RES 1.82K OHM 1/2W 1% . . . . . . . . . . . . . . . . .
RES 2.61K OHM 1/2W 1% . . . . . . . . . . . . . . . . .
RES 2.74K OHM 1/2W 1% . . . . . . . . . . . . . . . . .
RES 4.75K OHM 1/2W 1% . . . . . . . . . . . . . . . . .
RES 9.31K OHM 1/2W 1% . . . . . . . . . . . . . . . . .
RES 10K OHM 1/2W 1% . . . . . . . . . . . . . . . . . .
RES 12.4K OHM 1/2W 1% . . . . . . . . . . . . . . . . .
RES 31.6K OHM 1/2W 1% . . . . . . . . . . . . . . . . .
RES 41.2K OHM 1/2W 1% . . . . . . . . . . . . . . . . .
RES 100K OHM 1/2W 1% . . . . . . . . . . . . . . . . .
RES 162K OHM 1/2W 1% . . . . . . . . . . . . . . . . .
RES 1MEG OHM 1/2W 1% . . . . . . . . . . . . . . . .
RES 10MEG OHM 1/2W 1% . . . . . . . . . . . . . . .
POT 10K 1/2W/.3W 10% . . . . . . . . . . . . . . . . . .
POT 1K OHM 1/2W 10% . . . . . . . . . . . . . . . . . .
MOV 50VRMS 4500AMP 15J . . . . . . . . . . . . . .
RELAY REED SPDT 5VDC . . . . . . . . . . . . . . . .
SW PB SPST-N.O. MOM . . . . . . . . . . . . . . . . . .
HEADER 3 CKT STRAIGHT . . . . . . . . . . . . . . .
HDR 10C 2ROW VERTICAL . . . . . . . . . . . . . . .
HDR 20C 2ROW VERTICAL . . . . . . . . . . . . . . .
HEADER 12 CRKT STRAIGHT . . . . . . . . . . . . .
Rev. E: 09-19-95
1
2
1
1
2
2
1
1
4
4
3
3
1
3
1
1
1
2
2
1
1
1
3
1
5
1
3
1
1
1
1
1
4
3
4
1
6
1
3
2
3
1
3
1
1
2
1
1
1
4
3
1
1
C020 C022 C023 C026 C027 C029
C033 C036 C058 C059
C030
C008 C009
C028
C001
C016 C025
C015 C024
C032
C031
C034 C037 C040 C042
C035 C038 C039 C041
C011 C017 C021
R028 R029 R064
R012
R019 R020 R027
R011
R080
R053
R035 R036
R021 R022
R015
R023
R014
R050 R051 R081
R054
R016 R017 R018 R026 R033
R048
R009 R010 R075
R032
R030
R046
R037
R070
R007 R008 R025 R063
R034 R043 R049
R042 R044 R045 R047
R038
R004 R024 R031 R039 R052 R061
R041
R003 R059 R060
R057 R058
R002 R062 R065
R040
R001 R005 R074
R013
R006
R055 R056
RV001
K001
S001
JP001 JP002 JP003 JP004
J005 J006 J007
J004
J008
888-2333-001
WARNING: Disconnect primary power prior to servicing.
7-5
DIGIT™
610 1108 000. . . . . . HDR,14PIN,1ROW,STRT,POL . . . . . . . . . . . . . .
610 1145 000. . . . . . HDR, 6PIN, 1ROW, STRT,POL . . . . . . . . . . . . . .
610 1160 000. . . . . . HDR 4C 1 ROW STRAIGHT PCB . . . . . . . . . . . .
612 1184 000. . . . . . JUMPER .1" CENTERS . . . . . . . . . . . . . . . . . . .
612 1341 000. . . . . . RECP, D, 15 PIN STRAIGHT . . . . . . . . . . . . . . .
614 0790 000. . . . . . TERM MODULE,1C PC MTG 236 . . . . . . . . . . . .
839 8120 005. . . . . . SCHEM, REGULATOR . . . . . . . . . . . . . . . . . . . .
843 5295 005. . . . . . PWB, REGULATOR . . . . . . . . . . . . . . . . . . . . . .
917 2335 011. . . . . . FIRMWARE, A2, U3, CONTROL . . . . . . . . . . . . .
999 2761 001. . . . . . HARDWARE LIST, REGULATOR . . . . . . . . . . . .
*** E N D O F R E P O R T ***
7-6
1
1
2
4
1
2
0
1
1
1
J003
J001
J002 J011
XJP001 XJP002 XJP003 XJP004
J009
TB1-1 TB1-2
U003
888-2333-001
WARNING: Disconnect primary power prior to servicing.
Rev. E: 09-19-95
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