RF Technology | Eclipse Series | Operating instructions | RF Technology Eclipse Series Operating instructions

RF Technology Eclipse Series Operating instructions
Eclipse Series
RF Technology
rfinfo@rftechnology.com.au
February 2005 Revision 2
T350 / T500 Transmitter
Operation and Maintenance Manual
This manual is produced by RF Technology Pty Ltd
10/8 Leighton Place, Hornsby NSW 2077 Australia
Copyright © 1998 RF Technology
CONTENTS
CONTENT
Contents
1
Operating Instructions
1.1
Front Panel Controls and Indicators
1.1.1
PTT
1.1.2
Line
1.1.3
PWR LED
1.1.4
TX LED
1.1.5
ALARM LED
1.1.6
ALC LED
1.1.7
REF LED
1.1.8
TEST MIC
5
5
5
5
6
6
6
6
6
7
2
Transmitter Internal Jumper Options
2.1
JP2: EPROM type
2.2
JP3: Dc Loop PTT
2.3
JP4: Audio Input Source
2.4
JP5: 600? Termination
2.5
JP6: Input Level Attenuation
2.6
JP7: Audio Response
2.7
JP8: Sub-audible Tone source
2.8
JP9/10/11: dc Loop Configuration
2.9
JP16: Direct Digital Input (Rev 4 or Higher)
2.10 JP17: Bypass Low Pass Filter (Rev 4 or Higher)
2.11 JP19: Alarm Output (Rev 4 or Higher)
2.12 JP22: Use Tone- as a Direct Digital Input (Rev 4 or Higher)
2.13 JP23: Connection of DMTX Board (Rev 4 or Higher)
7
7
7
7
7
8
8
8
8
8
9
9
9
9
3
Transmitter I/O Connections
3.1
25 Pin Connector
3.2
Rear Panel Connectors
10
10
10
4
Channel and Tone Frequency Programming
12
5
Circuit Description
5.1
VCO Section
5.2
PLL Section
5.3
Power Amplifier
5.4
Temperature Protection
5.5
600Ω line Input
5.6
Direct Coupled Audio Input
5.7
Local Microphone Input
5.8
CTCSS and Tone Filter
5.9
Audio Signal Processing
5.10 PTT and DC Remote Control
5.11 Micro-processor Controller
5.12 Voltage Regulator
12
12
12
13
13
13
13
14
14
14
15
15
16
6
Field Alignment Procedure
6.1
Standard Test Conditions
6.2
VCO Alignment
16
17
RF Technology T350/T500
Page 2
CONTENTS
6.3
6.4
6.5
6.6
6.7
6.8
7
TCXO Calibration
Modulation Balance
Tone Deviation
Deviation
Line Input Level
Output Power
CONTENTS
17
17
18
18
18
19
Specifications
7.1
Overall Descri ption
7.1.1
Channel Capacity
7.1.2
CTCSS
7.1.3
Channel Programming
7.1.4
Channel Selection
7.1.5
Micro-processor
19
19
19
19
20
20
20
7.2
Physical Configuration
20
7.3
Front Panel Controls, Indicators and Test Points
7.3.1
Controls
7.3.2
Indicators
7.3.3
Test Points
20
20
20
20
7.4
Electrical Specifications
7.4.1
Power Requirements
7.4.2
Frequency Range and Channel Spacing
7.4.3
Frequency Synthesizer Step Size
7.4.4
Frequency Stability
7.4.5
Number of Channels
7.4.6
Antenna Impedance
7.4.7
Output Power
7.4.8
Transmit Duty Cycle
7.4.9
Spurious and Harmonics
7.4.10
Carrier and Modulation Attack Time
7.4.11
Modulation
7.4.12
Distortion
7.4.13
Residual Modulation and Noise
7.4.14
600Ω Line Input Sensitivity
7.4.15
HI-Z Input
7.4.16
Test Microphone Input
7.4.17
External Tone Input
7.4.18
External ALC Input
7.4.19
T/R Relay Driver
7.4.20
Channel Select Input / Output
7.4.21
DC Remote Keying
7.4.22
Programmable No-Tone Period
7.4.23
Firmware Timers
7.4.24
CTCSS
21
21
21
21
21
21
21
21
22
22
22
22
22
22
22
22
22
22
23
23
23
23
23
23
24
7.5
Connectors
7.5.1
Antenna Connector
7.5.2
Power and I/O Connector
7.5.3
Test Connector
24
24
24
24
RF Technology T350/T500
Page 3
CONTENTS
CONTENTS
A
Engineering Diagrams
A.1
Block Diagram
A.2
Circuit Diagrams
A.3
Component Overlay Diagrams
26
26
26
26
B
Parts List
35
RF Technology T350/T500
Page 4
1 OPERATING INSTRUCTIONS
WARNING
Changes or modifications not expressly approved by
RF Technology could void your authority to operate this
equipment. Specifications may va ry from those given in
this document in accordance with requirements of local
authorities. RF Technology equipment is subject to
continual improvement and RF Technology reserves the
right to change performance and specification without
further notice.
1
Operating Instructions
1.1
Front Panel Controls and Indicators
1.1.1
PTT
A front-panel push-to-talk (PTT) button is provided to facilitate bench and field tests
and adjustments. The button is a momentary action type. When keyed, audio from the
line input is disabled so that a carrier with sub-tone is transmitted. The front-panel
microphone input is not enabled in this mode, but it is enabled when the PTT line on
that socket is pulled to ground.
1.1.2
Line
The LINE trimpot is accessible by means of a small screwdriver from the front panel of
the module. It is used to set the correct sensitivity of the line and direct audio inputs. It
is factory preset to give 60% of rated deviation with an input of 0dBm (1mW on 600Ω
equivalent to 775mV RMS or about 2.2V peak-to-peak) at 1kHz. The nominal 60%
deviation level may be adjusted by measuring between pins 6 and 1 on the test socket,
and adjusting the pot. By this means an input sensitivity from approximately -30dBm to
+10dBm may be established.
An internal jumper provides a coarse adjustment step of 20dB. Between the jumper and
the trimpot, a wide range of input levels may be accommodated.
RF Technology T350/T500
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1 OPERATING INSTRUCTIONS
1.1.3 PWR LED
LED Flash Cadence
5 flashes, pause
4 flashes, pause
3 flashes, pause
2 flashes, pause
1 flash, pause
LED ON continuously
Fault Condition
Synthesizer unlocked
Tuning voltage out of range
Low forward power
High reverse (reflected) power
Low dc supply voltage
Transmitter timed out
Table 1: Interpretations of LED flash cadence
Indication
Flashing, 8 per second
Flashing, 4 per second
Flashing, 2 per second
Flashing, 1 per second
Continuous
Fault Condition
Synthesizer unlocked
Tuning voltage outside correct range
Low forward power
High reverse power
dc supply voltage low or high
Table 2: Interpretations of LED flash speed, for early models
1.1.3
POWER LED
The PWR LED shows that the dc supply is connected to the receiver.
1.1.4
TX LED
The TX LED illuminates when the transmitter is keyed. It will not illuminate (and an
Alarm cadence will be shown) if the synthesizer becomes unlocked, or the output
amplifier supply is interrupted by the microprocessor.
1.1.5
ALARM LED
The Alarm LED can indicate several fault conditions if they are detected by the self test
program. The alarm ind icator shows the highest priority fault present. Receivers using
software issue 5 and higher use the cadence of the LED flash sequence to indicate the
alarm condition. Refer to table 1. Receivers using software issue 4 and lower use the
LED flash rate to indicate the alarm condition. Refer to table 2.
1.1.6
ALC LED
The ALC LED indicates that the transmitter output power is being controlled by an
external amplifier through the external ALC input
1.1.7
REF LED
The REF LED indicates that the synthesiser frequency reference is locked to an external
reference.
RF Technology T350/T500
Page 6
2
TRANSMITTER INTERNAL JUMPER OPTIONS
1.1.8
TEST MIC
The TEST MIC. DIN socket is provided for use with a standard mobile or handset 200
Ohm dynamic microphone. The external audio inputs are disabled when the TEST
MIC’S PTT is on.
2
Transmitter Internal Jumper Options
In the following subsections an asterisk (*) signifies the standard (Ex-Factory)
configuration of a jumper.
2.1
JP2: EPROM Type
Condition
27C256
27C64
Position
2-3 *
1-2
2.2 JP3: Dc Loop PTT
This jumper enables or disables the keying of the PTT function by means of a dc signal
passed down the 600Ω line input pair. When enabled, JP9-JP11 control how the dc
signal is configured with respect to an internal opto-coupler.
Condition
dc loop connected (enabled)
dc loop not connected (bypassed)
2.3
Position
1-2 *
2-3
JP4: Audio Input Source
Either the 600Ω or the high-Z balanced inputs may be selected.
Condition
600Ω Input
High- impedance Input
2.4
Position
2-3 *
1-2
JP5: 600 ? Termination
Normally the Line Input is terminated in 600? .
removed by choosing the alternate position.
Condition
600? Termination
No Termination
RF Technology T350/T500
The 600 ohm termination can be
Position
1-2*
2-3
Page 7
2.5 JP6: Input Level Attenuation
2.5
2 TRANSMITTER INTERNAL JUMPER OPTIONS
JP6: Input Level Attenuation
This jumper permits coarse input sensitivity to be set. In the default position, the unit
expects a line level of 0dBm (nominal) at its Line Input. In the alternate position,
levels of +20dBm (nominal) can be accepted.
Condition
0dB attenuation
20dB attenuation
2.6
Position
1-2 *
2-3
JP7: Audio Response
Condition
750 uSec. pre-emphasis
Flat response
2.7
Position
1-2 *
2-3
JP8: Sub-audible Tone Source
Condition
Interna l CTCSS
External input
2.8
Position
1-2, 4-5 *
2-3, 5-6
JP9/10/11: dc Loop Configuration
DC loop current on the audio pair, is normally sourced externally. The Eclipse exciters
loop the current through an opto-isolator. when the current flows the exciter keys up.
An alternative arrangement is possible.
external device can provide the dc loop.
The exciter can source the current and an
These three jumpers select the appropriate mode.
Condition
Current Loop Input
12Vdc Loop source
2.9
JP9
ON
OFF
JP10
OFF
ON
JP11
OFF *
ON
JP16: Direct Digital Input (pcb 30/9103/0009 or later)
Some trunking controllers have digital encoding schemes which operate to very low
frequencies. The elliptical filter, used as a 250Hz low pass filter in the tone section,
can cause excessive pulse edge distortion of the truinking controller’s digital signals.
In such circumstances, JP16 allows a user to bypass the low and high pass filters in the
tone input section. See also 2.12 - JP22: If direct tone input is selected, then JP22
should be removed (open).
RF Technology T350/T500
Page 8
2 TRANSMITTER INTERNAL JUMPER OPTIONS 2.10 JP17: Bypass Low Pass Filter
Condition
Normal Tone Input
Direct Tone Input
Position
1-2*
2-3
2.10 JP17: Bypass Low Pass Filter
(pcb 30/9103/0009 or later)
Some trunking controllers have digital encoding schemes that require the low pass filter
in the tone input section to be bypassed. JP17 allows this. Normally JP17 is open
circuit. Placing a link across it will bypass the low pass filter.
In conjunction with this change, it sometimes may be necessary, depending upon the
type of trunking controller used, to add a 100K resistor in the place reserved for R157.
2.11 JP19: Alarm Output (pcb 30/9103/0009 or later)
The main audio transformer (T1), is connected to the Line IPI and Line IP4 pins on P3.
These two pins constitute the main audio input for the exciter. The centre taps of the
audio transformer, though, are brought out on Line IP2 and Line IP3. These can be
used as alternate audio inputs for larger signals, or to directly access the dc loop sense
circuitry. JP19 allows an alternate use for Line IP2 (pin 7 of P3). In the alternate
position for JP19, the ALARM signal (the signal that drives the ALARM LED itself) is
connected to pin 7 of P3. The ALARM signal when asserted is low active; when
unasserted it pulls high to +9.4V through an LED and a 680 ohm resistor.
Condition
P3, pin 7 connects to centre tap of transformer T1
P3, pin 7 connects to ALARM signal
Position
1-2*
2-3
2.12 JP22: Use Tone- as a Direct Digital Input
(pcb 30/9103/0009 or later)
JP22 is normally shunted with a jumper, which connects Tone- on P3 (pin 18), as the
negative leg of the Toner input pair. Removing this jumper disconnects Tone- from
this path and allows the use of the Tone- pin to be used as s direct digital input. See
also 2.9 - JP16: If the jumper is removed, then JP16 should be in the alternative position
(Direct Tone Input).
2.13 JP23: Connection of DMTX Board
(pcb 30/9103/0009 or later)
When the DMTX board is connected to an exciter, there is provision for digital or audio
modulation of the reference oscillator and VCO. The digital signal is input via the DB9
rear connector and the audio input signal is via the Line inputs on the standard DB25
rear panel connector.
RF Technology T350/T500
Page 9
3 TRANSMITTER I/O CONNECTIONS
Condition
N DMTX board
DMTX board connected
3
3.1
Position
1-2, 5-6*
2-3, 4-5
Transmitter I/O Connections
25 Pin Connector
The D-shell 25 pin connector is the main interface to the transmitter. The pin
connections are described in table 3.
Function
DC power
Channel Select
RS232 Data
600Ω Line
Signal
+12 Vdc
0 Vdc
1
2
4
8
10
20
40
80
In
Out
High
Low
150Ω / Hybrid
Direct PTT input
T/R Relay driver output
Sub-Audible Tone Input
High-Z Audio Input
[+]
[-]
[+]
[-]
External ALC input
Pins
1, 14
13, 25
21
9
22
10
23
11
24
12
15
2
20
6
7
19
3
16
5
18
4
17
8
Specification
+11.4 to 16 Vdc
Ground
BCD Coded
0 = Open Circuit
or 0 Vdc
1 = +5 to +16 Vdc
Test and Programming use
9600, 8 data 2 stop bits
Transformer Isolated
Balanced 0dBm Output
Ground to key PTT
Open collector,250mA/30V
>10kΩ, AC coupled
(1-250Hz)
>10kΩ, AC coupled
(10Hz-3kHz)
<0.5V/1mA to obtain
>30dB attenuation, O/C
for maximum power
Table 3: Pin connections and explanations for the main 25-pin, D connector.
3.2
Rear Panel Connectors
The exciter and receiver can be supplied with optional rear panel connectors that bring
out the more important signals available on P1, the rear panel DB25 connector.
Figures 1 and 2 show the rear panel connectors, and Table 4 shows the signals that are
brought out onto spade connectors for these daughter boards. The spade connectors
(2.1 x 0.6 x 7mm) are captive/soldered at the labelled points.
RF Technology T350/T500
Page 10
3 TRANSMITTER I/O CONNECTIONS
3.2 Rear Panel Connectors
Fig 1
RX PCB
Fig 2
TX PCB
The Receiver and Transmitter modules plug into the back plane DB25/F connectors
To configure: Solder wire connections between appropriate points.
Receiver
DB25/F
1, 14
RX
PCB
+12V
DESCRIPTION
+12V DC SUPPLY
TX
PCB
+12V
Transmitter
DB25/F
1, 14
2
TXD
TX Data
TXD
2
15
RXD
RX Data
RXD
15
3
COR+
Carrier Operate Sw+
PressToTalk input
PTT
3
16
COR-
Carrier Operate Sw-
Tx/Rx output
T/R
16
4
TONE
Subtone output
Hi Z audio input+
AUD+
4
17
AUDIO
Audio output
Hi Z audio input-
AUD-
17
5
AGND
Audio Ground
Ext tone input+
TONE+
5
18
DISC
Discriminator output
Ext tone input-
TONE-
18
6
LINE+
Line output+
Line input+
LINE+
6
20
LINE-
Line output-
Line input-
LINE-
20
8
EXT SQ
Ext Squelch input
Auto Level Control
ALC
8
13, 25
GND
Ground, 0V
GND
13, 25
21
BCD 1
Channel select 1’s digit
BCD 1
21
9
BCD 2
Channel select 1’s digit
BCD 2
9
22
BCD 4
Channel select 1’s digit
BCD 4
22
10
BCD 8
Channel select 1’s digit
BCD 8
10
23
BCD 10
Channel select 10’s digit
BCD 10
23
11
BCD 20
Channel select 10’s digit
BCD 20
11
24
BCD 40
Channel select 10’s digit
BCD 40
24
12
BCD 80
Channel select 10’s digit
BCD 80
12
Table 4
RF Technology T350/T500
Page 11
4 CHANNEL AND TONE FREQUENCY PROGRAMMING
4
Channel and Tone Frequency Programming
Channel and tone frequency programming is most easily accomplished with RF
Technology TecHelp software or the Service Monitor 2000 software. This software can
be run on an IBM compatible PC and provides a number of additional useful facilities.
DOS and 32-bit versions are available.
TecHelp allows setting of the adaptive noise squelch threshold, provides a simple means
of calibrating the forward and reverse power detectors, setting the power alarm preset
levels, and enabling transmitter hang time and timeout time limits. TecHelp can be
supplied by your dealer, distributor or by contacting RF Technology directly.
5
Circuit Description
The following descriptions should be read as an aid to understanding the block and
schematic diagrams given in the appendix of this manual.
5.1
VCO Section
The Voltage Controlled Oscillator uses a junction FET which oscillates at the required
transmitter output frequency. A varactor diode is used by the PLL circuit to keep the
oscillator on the desired frequency. Transistor Q20 is used as an active filter to reduce
the noise on the oscillator supply voltage. The VCO is keyed ON by the
microcontroller through Q10. It is keyed ON when any of the PTT inputs are active and
OFF at all other times.
The VCO output is amplified and buffered by monolithic amplifiers MA2 and MA3
before being fed to the PLL IC U6.
Amplifiers MA1, MA4 and MA5 increase the VCO output to approximately 4 mW to
drive the power amplifier. MA1 is not switched on until the PLL has locked and had
time to settle. This prevents any momentary off channel transmission when the
transmitter is keyed.
5.2
PLL Section
Temperature compensated crystal oscillator XO1 is the frequency reference source for
the PLL Synthesizer. The frequency stability of XO1 is better than 1 ppm and it can be
synchronized to an external reference for improved stability. External reference option
board 11/9119 is required when using an external reference.
XO1 is frequency modulated by the processed transmit audio signal from U7b. This
extends the modulation capability down to a few Hz for sub-audible tones and digital
squelch codes. A two point modulation scheme is used with the audio also being fed to
the VCO to modulate the higher audio frequencies.
The 12.8 MHz output of XO1 is amplified by Q22 to drive the reference input of the
PLL synthesizer IC U6. This IC is a single chip synthesizer which includes a 1.1 GHz
RF Technology T350/T500
Page 12
5 CIRCUIT DESCRIPTION
5.3 Power Amplifier
pre-scaler, programmable divider, reference divider and phase/frequency detector. The
frequency data for U6 is supplied through serial data link by the microprocessor.
The phase detector output signals of U6 are used to control two switched current
sources. The output of the positive and negative sources (Q3 and Q6) produces the
tuning voltage which is smoothed by the loop filter components to bias the VCO
varactor diode D3.
5.3
Power Amplifier
The 4 mW output from the main board connects to the power amplifier board through a
short miniature 5Ω coaxial cable.
Q2 on the power amplifier board increases the signal to approximately 200 mW. The
bias current of Q2 is controlled by Q1 and the power leveling circuitry to adjust the
drive to the output module U2.
U2 increases the power to 10-30 watts (depending upon options) before it is fed to the
directional coupler, low pass filter and output connector. The directional coupler
detects the forward and reverse power components and provides proportional dc
voltages which are amplified by U1a and U1b. The forward and reverse voltages from
U1a and U1b are compared to the DC reference voltage from RV1. The difference is
amplified by U1c, Q3 and Q4.
The resulting control voltage supplies Q2 through R10, R12 and completes the power
leveling control loop.
5.4
Temperature Protection
Thermistor RT1 on the power amplifier board is used to sense the case temperature of
the output module U2. If the case temperature rises above 90 degrees C., the voltage
across RT1 will increase and transistor Q5 will be turned on. This reduces the dc
reference voltage to the power regulator which in turn reduces the outpower by 6-10dB.
5.5
600Ω Line Input
The 600Ω balanced line input connects to line isolation transformer T1. T1 has two
150Ω primary windings which are normally connected in series for 600Ω lines. The
dual primary windings can be used to provide DC loop PTT signaling or a 2/4 wire
hybrid connection. All four leads are available at the rear panel system connector.
The secondary of T1 can be terminated with an internal 600Ω load through JP5 or left
un-terminated in high impedance applications.
5.6
Direct Coupled Audio Input
A high impedance (10kΩ) direct AC coupled input is available at the system connector.
The direct coupled input connects to U9a which is configured as a unity gain bridge
amplifier.
RF Technology T350/T500
Page 13
5.7 Local Microphone Input
5 CIRCUIT DESCRIPTION
The bridge configuration allows audio signal inversion by interchanging the positive
and negative inputs and minimizes ground loop problems. Both inputs should be
connected, with one lead going to the source output pin and the other connected to the
source audio ground.
5.7
Local Microphone Input
The local microphone input is provided for use with a standard low impedance dynamic
microphone. The microphone output is amplified by U9a before connecting to analogue
switch U10a. U10b inverts the local microphone PTT input to switch U10a ON when
the microphone PTT button is pressed. U10a is OFF at all other times.
The local microphone audio has priority over the other inputs. Activation of the local
microphone PTT input switches OFF the audio from the line or direct inputs through
D16 and U10c.
5.8
CTCSS and Tone Filter
The CTCSS encoder module H1, under control of the main microprocessor U13, can
encode all 38 EIA tones and (on some models) additional commonly-used tones.
The tone output of H1 connects to jumper JP8 which is used to select either H1 or an
external tone source. The selected source is coupled to U9c which is a balanced input
unity gain amplifier. The buffered tone from U9c is fed to 300 Hz low pass filter U7c.
RV3, the tone deviation trimmer, is used to adjust the level of the tone from U7c before
it is combined with the voice audio signal in the summing amplifier U7a.
Back to back diodes D4 and D5 limit the maximum tone signal amplitude to prevent
excessive tone deviation when external tone sources are used.
5.9
Audio Signal Processing
Jumper JP4 selects either the line or direct input source. The selected source is then
connected to JP6. JP6 can be removed to provide 20 dB attenuation when the input
level is above 10 dBm to expand the useful range of the line level trimmer RV4. The
wiper of RV4 is coupled to the input of the input amplifier U9d. U9d provides a
voltage gain of ten before connecting to the input of analogue switch U10c.
The outputs of U10a and U10c are connected to the frequency response shaping
networks C52, R133 (for 750µs pre-emphasis) and C61, R55 (for flat response). JP7
selects the pre-emphasized or flat response.
The audio signal is further amplified 100 times by U7d. U7d also provides the
symmetrical clipping required to limit the maximum deviation. The output level from
U7d is adjusted by RV1, the deviation adjustment, before being combined with the tone
audio signal in the summing amplifier U7a.
The composite audio from U7a is fed through the 3Khz low pass filter U7b. When the
links on JP23 are in their default state, the filtered audio is coupled to the TCXO voltage
tuning input and the modulation balance trimmer RV2. RV2, R99 and R98 attenuate
the modulation signal before applying it to the VCO via varactor D3.
RF Technology T350/T500
Page 14
5 CIRCUIT DESCRIPTION
5.10 PTT & DC Remote Control
When a DMTX board option is required, jumper JP23 allows the audio paths to be rerouted. The DMTX board provides for an external digital modulation input signal.
When the two links on JP23 are positioned in the middle of the 6 pin header, the audio
from the exciter is passed to the DMTX board via pin5 of JP5, where the signal is
conditioned and then returned from the DMTX board via pin 2 of JP15, and passed to
the two modulation points.
RV2 adjusts level of the audio used to modulate the VCO. This primarily effects the
deviation of audio frequencies above 500Hz. RV2 is used to balance the high and low
frequency deviation to obtain a flat frequency response relative to the desired
characteristic.
5.10
PTT and DC Remote Control
Two main PTT inputs are provided. The first, a direct logic level input, is connected to
pin 3 of the system connector. The transmitter can be keyed by applying a logic low or
ground on pin 3. Pin 3 connects to the PTT logic and microprocessor through D10.
DC current loop control can be used for remote PTT operation. The current loop can be
configured by JP9, JP10 and JP11 for use with either a remote free switch or a remote
switched source.
Opto-isolator ISO1 is used to isolate the loop current signal from the transmitter PTT
logic. The loop current passes through the input of ISO1 and the output of ISO1
connects to the PTT logic.
A bridge consisting of diodes D6, D8, D9 and D14 ensures correct operation regardless
of the current polarity. Q17 limits the current and D7 limits the voltage input to ISO1.
Any low voltage current source capable of providing 2 mA at 4 V or switching circuit
with less than 4.8kΩ loop resistance can be used to switch the DC loop.
The test PTT button on the front panel and the local microphone PTT button will also
key the transmitter. Both of these also mute the line audio input. The microphone line
also enables that audio input.
A DMTX board can also cause the exciter to key up. When a TX(or TTL_TX) signal
is received by the DMTX board, it pulls pin 6 of JP15 low, which, in turn asserts the
PTT_WIRE_OR signal, causing the microprocessor (U13) to key the exciter up.
5.11
Microprocessor Controller
The microprocessor controller circuit uses a single-chip eight bit processor and several
support chips. The processor U13 includes non-volatile EE memory for channel
frequencies, tones, and other information. It also has an asynchronous serial port, a
synchronous serial port and an eight bit analogue to digital converter.
The program is stored in U5, a CMOS EPROM. U4 is an address latch for the low order
address bits. U2 is used to read the channel select lines onto the data bus. U11 is an
address decoder for U5 and U2. U3 is a supervisory chip which keeps the processor
reset unless the +5 Volt supply is within operating limits. U1 translates the
asynchronous serial port data to standard RS232 levels.
RF Technology T350/T500
Page 15
5.12 Voltage Regulator
5 CIRCUIT DESCRIPTION
The analogue to digital converter is used to measure the forward and reverse power,
tuning voltage and dc supply voltage.
If the processor detects that the PTT_WIRE_OR signal is asserted low, it will attempt to
key the exciter up. It will first attempt to key the VCO through Q10, and if the LD pin
goes high, it will switch the 9.2 Volt transmit line through Q14 and Q16. Asserting
Q16 has the effect of also asserting the yellow Tx LED (D12) on the front panel,
enabling the local 25W power amplifier, and causing the T/R Relay output to be pulled
low. D24 is 30 volt zener which protects Q25 from both excessive voltages or reverse
voltages.
Should there be a problem with either the tuning volts, or the battery voltage, the VCO
locking, the forward power, or the reverse power, the microprocessor will assert the
ALARM LED through Q1. Depending on the setting of Jumper JP19, the ALARM
signal can be brought out on pin 7 of P3.
5.12
Voltage Regulator
The dc input voltage is regulated down to 9.4 Vdc by a discrete regulator circuit. The
series pass transistor Q23 is driven by error amplifiers Q8 and Q18. Q9 is used to start
up the regulator and once the circuit turns on, it plays no further part in the operation.
The +5 Volt supply for the logic circuits is provided by an integrated circuit regulator
U14 which is run from the regulated 9.4 Volt supply.
Jumper JP18 is not normally fitted to the board, and is bridged with a 12mil track on the
component side of the board. It is provided so that the 9.4V load can be isolated from
the supply by the service department to aid in fault finding.
Jumper JP20 and JP21 are also not normally fitted on the board, and are usually bridged
with a 12mil track on the component side. they allow U14 to be isolated from its input,
or its output, or both.
6
Field Alignment Procedure
The procedures given below may be used to align the transmitter in the field. Normally,
alignment is only required when changing operating frequencies, or after component
replacement.
The procedures below do not constitute an exhaustive test or a complete alignment of
the module, but if successfully carried out are adequate in most circumstances.
TCXO calibration may be periodically required owing to normal quartz crystal aging. A
drift of 1ppm/year is to be expected.
Each alignment phase assumes that the preceding phase has been successfully carried
out, or at least that the module is already in properly aligned state with respect to
preceding conditions.
RF Technology T350/T500
Page 16
6 FIELD ALIGNMENT PROCEDURE
6.1
6.1 Standard Test Condition
Standard Test Condition
The following equipment and conditions are assumed unless stated otherwise:
•
AF signal generator with 600Ω impedance, 150-3000Hz frequency range, with level
set to 387mV RMS.
•
Power supply set to 13.8Vdc, with a current capable of >5A.
•
RF 50Ω load, 30W rated, return loss <-20dB.
•
Jumpers set to factory default positions.
6.2
VCO Alignment
1. Select a channel at the center frequency (half way between the highest and lowest
frequencies for the model in question).
2. Disconnect the Audio input (no signal input).
3. Key the PTT line.
4. Measure the voltage between pins 9 and 1 of the test socket (TUNE V), and adjust
C99 to obtain 4.5±0.25V, while the TX LED is ON and the ALARM LED is OFF.
6.3
TCXO Calibration
1. Select a channel at the center frequency (half way between the highest and lowest
frequencies for the model in question).
2. Disconnect the Audio input (no signal input).
3. Key the PTT line.
4.
6.4
Measure the carrier frequency at the output connector, and adjust XO1 until the
correct carrier frequency is measured, ±50Hz.
Modulation Balance
1.
Set RV3 fully counter clockwise (CCW) (sub-tone off).
2.
Set RV1 fully clockwise (CW) (maximum deviation)
3.
Set RV2 mid-position
4.
Set JP7 for flat response
5.
Key the transmitter on
RF Technology T350/T500
Page 17
6.5 Tone Deviation
6 FIELD ALIGNMENT PROCEDURE
6. Set the audio input to 150Hz, 0dBm
7. Measure deviation and adjust RV4 (line level) for a deviation of 5kHz (2.5kHz for
narrow band transmitters).
8. Set the audio input to 1.5kHz, 0dBm.
9. Adjust RV2 (Mod. Bal.) for a deviation of 5kHz (2.5kHz for narrow band
transmitters)
10. Repeat steps 6-9 until balance is achieved.
11. Key the transmitter off.
12. Return JP7 to its correct setting.
13. Carry out the Deviation (section 6.6) and Tone Deviation (section 6.5) alignment
procedures.
6.5
Tone Deviation
1.
Remove the audio input.
2.
Key the transmitter on.
3.
Adjust RV3 for the desired deviation in the range 0-1kHz. 1
(CTCSS) coding is not to be used, adjust RV3 fully CCW.
6.6
If sub-tone
Deviation
1.
Set RV4 (Line Level) fully clockwise (CW).
2.
Set the audio to 1kHz, 0dBm, on the line input.
3.
Key the transmitter on..
4.
Adjust RV1 (Set Max. Deviation) for a deviation of 5kHz (2.5kHz for narrow
band transmitters).
5.
Key the transmitter off.
6.
Carry out the Line Input Level alignment procedure (section 6.7)
6.7
1.
Line Input Level
Set the audio to 1kHz, 0dBm, on the line input, or use the actual signal to be
transmitted.
________________________________
1
The factory default is 500Hz for wide band (5kHz maximum deviation) and 250Hz for narrow band
channels.
RF Technology T350/T500
Page 18
6 FIELD ALIGNMENT PROCEDURES
6.8 Output Power
2.
Key the transmitter on.
3.
Adjust RV4 (line level) for 60% of system deviation (3kHz or 1.5kHz for narrow
band systems).
4.
If the test signal is varying, RV4 may be adjusted to produce a level of 234mV
RMS or 660mVp-p at the audio voltage test connector pin 6 to pin 1.
5.
Key the transmitter off.
6.8
Output Power
1.
No audio input is required
2.
Key the transmitter on.
3.
Adjust RV1 on the power amplifier PCB for the desired power level at the output
connector. 2
4.
Key the transmitter off.
7.
SPECIFICATIONS
7.1
Overall Description
The transmitter is a frequency synthesized, narrow band FM unit, normally used to
drive a 50 watt amplifier. It can also be used alone in lower power applications.
Various models allow 2-25W of output power to be set across a number of UHF
frequency bands. All necessary control and 600Ω line interface circuitry is included.
7.1.1
Channel Capacity
Although most applications are single channel, it can be programmed for up to 100
channels, numbered 0 - 99. This is to provide the capability of programming all
channels into all of the transmitters used at a given site. Where this facility is used in
conjunction with channel-setting in the rack, exciter modules may be “hot-jockeyed” or
used interchangeably. This can be convenient in maintenance situations.
7.1.2
CTCSS
Full EIA sub-tone capability is built into the modules. The CTCSS tone can be
programmed for each channel. This means that each channel number can represent a
unique RF and tone frequency combination.
____________________
2
Be sure to set the power below the rated maximum for the model of transmitter. If in doubt, allow
1.5dB cable and connector losses, and assume that the maximum rated power is 15W. This means no
more than 10W at the end of a 1m length of test cable. This pessimistic procedure is safe on all models
manufactured at the time of writing.
RF Technology T350/T500
Page 19
7.1.3 Channel Programming
7.1.3
7 SPECIFICATIONS
Channel Programming
The channel information is stored in non-volatile memory and can be programmed via
the front panel test connector using a PC and RF Technology software.
7.1.4
Channel Selection
Channel selection is by eight channel select lines. These are available through the rear
panel connector. Internal presetting is also possible. The default (open-circuit) state is to
select channel 00.
A BCD active high code applied to the lines selects the required channel. This can be
supplied by pre-wiring the rack connector so that each rack position is dedicated to a
fixed channel. Alternatively, thumb-wheel switch panels are available.
7.1.5. Microprocessor
A microprocessor is used to control the synthesizer, tone squelch, PTT function and
facilitate channel frequency programming. With the standard software, RF Technology
modules also provide fault monitoring and reporting.
7.2
Physical Configuration
The transmitter is designed to fit in a 19 inch rack mounted sub-frame. The installed
height is 4 RU (178 mm) and the depth is 350 mm. The transmitter is 63.5 mm or two
Eclipse modules wide.
7.3
Front Panel Controls, Indicators, and Test Points
7.3.1
Controls
Transmitter Key - Momentary Contact Push Button
Line Input Level - screwdriver adjust multi-turn pot
7.3.2
Indicators
Power ON -
Green LED
Tx Indicator -
Yellow LED
Fault Indicator -
Flashing Red LED
External ALC -
Green LED
External Reference -
Green LED
RF Technology T350/T500
Page 20
7 SPECIFICATIONS
7.3.3
7.4 Electrical Specifications
Test Points
Line Input –
Pin 6 + Ground (pin 1)
Forward Power –
Pin 8 + Ground (pin 1)
Reverse Power –
Pin 4 + Ground (pin 1)
Tuning Voltage –
Pin 9 + Ground (pin 1)
Serial Data (RS-232) – Pins 2 / 3 + Ground (pin 1)
7.4
7.4.1
Electrical Specifications
Power Requirements
Operating Voltage - 10.5 to 16 Vdc with output power reduced below 12 Vdc
Current Drain - 5A Maximum, typically 0.25A Standby
Polarity - Negative Ground
7.4.2
Frequency Range and Channel Spacing
Frequency
330-365 MHz
360-380 MHz
375-400 MHz
403-420 MHz
430-450 MHz
450-520 MHz
7.4.3
25 kHz
T350C
T350A
T350B
T500A
T500D
T500B
12.5 kHz
T350CN
T350AN
T350BN
T500AN
T500DN
T500BN
Frequency Synthesizer Step Size
Step size is 10 / 12.5kHz or 5 / 6.25kHz, fixed, depending upon model
7.4.4
Frequency Stability
±1 ppm over 0 to +60 C, standard
±1ppm over -20 to +60 C, optional
7.4.5
Number of Channels
100, numbered 00 - 99
7.4.6
Antenna Impedance
50Ω
RF Technology T350/T500
Page 21
7.4.8 Transmit Duty Cycle
7.4.7
7 SPECIFICATIONS
Output power
Preset for 2-15 or 2-25W depending upon model
7.4.8
Transmit Duty Cycle
100% to 40C, de-rating to zero at 60C.
100% to 5000ft altitude, de-rating to zero at 15,000ft.
7.4.9
Spurious and Harmonics
Less than 0.25µW
7.4.10 Carrier and Modulation Attack Time
Less than 20ms. Certain models have RF envelope attack and decay times controlled in
the range 200µs< t r/f <2ms according to regulatory requirements.
7.4.11 Modulation
Type - Two point direct FM with optional pre-emphasis
Frequency Response - ±1 dB of the selected characteristic from 300 - 3000 Hz
Maximum Deviation - Maximum deviation preset to 2.5 or 5 kHz
7.4.12
Distortion
Modulation distortion is less than 3% at 1 kHz and 60% of rated system deviation.
7.4.13 Residual Modulation and Noise
The residual modulation and noise in the range 300 - 3000 Hz is typically less than 50dB referenced to rated system deviation.
7.4.14 600Ω Line Input Sensitivity
Adjustable from -30 to +10 dBm for rated deviation
7.4.15 HI-Z Input
Impedance - 10KΩ Nominal, balanced input
Input Level - 25mV to 1V RMS
7.4.16 Test Microphone Input
200Ω dynamic, with PTT
RF Technology T350/T500
Page 22
7 SPECIFICATIONS
7.4.18 External ALC Input
7.4.17 External Tone Input
Compatible with R500 tone output
7.4.18
External ALC Input
Output will be reduced 20dB by pulling the input down to below 1V. (Typically more
than 40dB attenuation is available.) The input impedance is ≅10kΩ, internally pulled
up to rail.
The external ALC input can be connected to the power control circuit in Eclipse
external power amplifiers.
7.4.19 T/R Relay Driver
An open collector transistor output is provided to operate an antenna change over relay
or solid state switch. The transistor can sink up to 250mA.
7.4.20 Channel Select Input / Output
Coding - 8 lines, BCD coded 00 - 99
Logic Input Levels - Low for <1.5V, High for >3.5V
Internal 10K pull down resistors select channel 00 when all inputs are O/C.
7.4.21 DC Remote Keying
An opto-coupler input is provided to enable dc loop keying over balanced lines or local
connections. The circuit can be connected to operate through the 600Ω line or through
a separate isolated pair.
7.4.22 Programmable No-Tone Period
A No-Tone period can be appended to the end of each transmission to aid in eliminating
squelch tail noise which may be heard in mobiles with slow turn off decoders. The NoTone period can be set from 0--5 seconds in 0.1 second increments. The No Tone
period operates in addition to the reverse phase burst at the end of each transmission. 3
7.4.23 Firmware Timers
The controller firmware includes some programmable timer functions.
Repeater Hang Time - A short delay or ``Hang Time'' can be programmed to be added
to the end of transmissions. This is usually used in talk through repeater applications to
prevent the repeater from dropping out between mobile transmissions. The Hang Time
can be individually set on each channel for 0 - 15 seconds.
Time Out Timer - A time-out or transmission time limit can be programmed to
automatically turn the transmitter off. The time limit can be set from 0-254 minutes
RF Technology T350/T500
Page 23
7.2.24 CTCSS
7 SPECIFICATIONS
in increments of one minute. The timer is automatically reset when the PTT input is
released.
____________________________________
3
The reverse phase burst is usually sufficient to eliminate squelch tail noise in higher-quality mobiles
7.4.24 CTCSS
CTCSS tones can be provided by an internal encoder or by an external source connected
to the external tone input. The internal CTCSS encoding is provided by a subassembly
PCB module. This provides programmable encoding of all EIA tones.
Some models encode certain extra tones.
Tone frequencies are given in table 4.
7.5
7.5.1
Connectors
Antenna Connector
Type N Female Mounted on the module rear panel
7.5.2
Power & I/O Connector
25-pin “D” Male Mounted on the rear panel
7.5.3
Test Connector
9-pin “D” Female mounted on the front panel
RF Technology T350/T500
Page 24
.
7 SPECIFICATIONS
Frequency
No Tone
67.0
69.4
71.9
74.4
77.0
79.7
82.5
85.4
88.5
91.5
94.8
97.4
100.0
103.5
107.2
110.9
114.8
118.8
123.0
127.3
131.8
136.5
141.3
146.2
151.4
156.7
159.8
162.2
165.5
167.9
171.3
173.8
177.3
179.9
183.5
186.2
189.9
192.8
196.6
199.5
203.5
206.5
210.7
218.1
225.7
229.1
233.6
241.8
250.3
254.1
EIA Number
RF Technology T350/T500
A1
B1
C1
A2
C2
B2
C3
A3
C4
B3
A4
B4
A5
B5
A6
B6
A7
B7
A8
B8
A9
B9
A10
B10
A11
B11
A12
B12
A13
B13
A14
B14
A15
B15
A16
B16
A17
Table 4: Tone Squelch Frequencies
Page 25
A
A
ENGINEERING DIAGRAMS
Engineering Diagrams
Most Eclipse transmitter modules contain two PCBs, a motherboard with the control
and signal generation circuitry (the exciter board), and an RF Power Amplifier board.
Certain models are equipped with optional functions on piggyback PCBs atop the
exciter motherboard. The exciter PCB typically has a few components whose values
vary from model to model depending upon operating frequency and local regulatory
constraints. The RF PA PCB varies from model to model but to a greater extent. At
least two different PCB layouts, and numerous variations, exist. This manual presents
the circuits and parts lists for two representative variants. When ordering spare parts be
sure to specify the model exactly, in case the part you require is different in value from
that specified in this manual.
Older models (predating this manual) may not be covered by this manual. However,
advances are evolutionary, and the information in this manual will be sufficient in most
cases to permit understanding and servicing of all models, past and present.
Versions of more detailed circuit schematics, printed on A3 paper, may be inserted or
bound with this manual towards the end. It is sometimes easier to work with these foldout diagrams because of their larger format. In case the inserts / fold-outs are missing
or damaged, the reader is advised that information in the figures included with the text
should be identical.
A.1
Block Diagram
Figure 1 shows the block signal flow diagram.
A.2
Circuit Diagrams
Figure 2 shows the detailed circuit diagram with component numbers and values for the
main (exciter) PCB. Figure 3 shows the detailed circuit diagram with component
numbers and values for the higher-power PA variation. Figure 4 shows the detailed
circuit diagram with component numbers and values for the lower-power PA variation.
A.3
Component Overlay Diagrams
Figure 5 shows the PCB overlay guide with component positions for the main (exciter)
PCB. Figure 6 shows the detailed circuit diagram with component numbers and values
for the higher-power PA variation. Figure 7 shows the detailed circuit diagram with
component numbers and values for the lower power PA variation.
RF Technology T350/T500
Page 26
A
1
Hi-Z INPUT
LINE IN
U9A
T1
ISO1
DIODE
D10
A/D
ASYNC.
DATA I/O
2
MICROPROCESSOR CONTROLER
U1-U5,U11,U13
250Hz
LOOP FILTER
SW SPDT
JP4
TEST KEY
3
U10B
U10A
D12
TX
MA5
U10C
CTCSS
MODULE
TEST MIC. AMP.
U9B
H1
+9.2 Vdc
TRANSMIT
SUPPLY
Q14,Q16
RV2
MOD.BAL.
MA4
BUFFER AMPLIFIER
3
EXT.TONE INPUT
INPUT AMP.
U9D
LINE LEVEL
RV4
D1
ALM
TONE DATA
TX ENABLE
TEST MIC.
Q10
V.C.O.
Q19,Q20
VCO ISOLATION AMPS
MA3
Q2-Q7,Q11,Q21
MA2
2
PTT
LINE IN
PTT IN
Tx DATA
Rx DATA
+13.8
TUNE V.
REV.POWER
PLL IC
12.5 KHz
STEPS
U4
LOCK
FWD.POWER
BCD CHANNEL CODE
XO1
1 PPM TCXO
DATA
B
C
D
1
V.C.O.
KEY
750 uSec.
PRE-EMPHASIS
JP8
MA1
+10 dBm
OUTPUT
4
CLIPPER
U7D
TONE AMP.
U9C
4
Q1,Q2
Q25
5
U7A
DIRECTIONAL
COUPLER
Date:
File:
Orcad B
Size
600 MHz LPF
3KHz LPF
U7B
9103 (UHF Tx Block)
6
2
JBS after RHM
Revision
15W
OUTPUT
POWER
ADJUST
RV1
31-Jul-1998
Sheet of
D:\RFT_MasterFiles\..\9103-TxUHF-block.sch
Drawn By:
Number
6
+8.0 V.REF.
RF TECHNOLOGY Pty Ltd
17/8 Leighton Place, Hornsby, 2077, Australia
SUMMING AMP.
U1A
EXT.ALC.
U1B
Title
T/R RELAY
SET TONE
DEVIATION
RV3
U2
+
AMP. MODULE
FWD.PWR.
-
+
REV.PWR.
SET MAX
VOICE DEVIATION
RV1
300 Hz LPF
U7C
VARIABLE
GAIN AMP.
Q3,Q4,U1C
P.A. BOARD
5
A
B
C
D
750 uSec. Pre-emphasis
Flat Response
Audio Frequency Response
0 dB
20 dB
Input Level Attenuation
Terminated 600 Ohm
Not terminated
600 ohm Audio Terminator
600 Ohm Line Input
Hi-Z Balanced Input
Audio Input Source Selection
dc Loop Connected
dc Loop Not Connected
600 Ohm Line dc Loop PTT Input
27C256
27C64
EPROM Type
Internal CTCSS
External Input
JP8 - Subaudible Tone Source
JP7 -
JP6 -
JP5 -
JP4 -
JP3 -
JP2-
TRANSMITTER Jumper Options
Position
1-2, 4-5 *
2-3, 5-6
Position
1-2 *
2-3
Position
1-2 *
2-3
Position
1-2 *
2-3
Position
2-3 *
1-2
Position
1-2 *
2-3
Position
2-3 *
1-2
JP9
ON
OFF
JP10
OFF
ON
JP11
OFF *
ON
* = Standard Factory Configuration
Audio modulation only
DMTX fitted for Digital and Audio modulation
JP23 – DMTX Digital and audio modulation option
No alarm output
Alarm - active low output at DB25 pin 7
JP19 – LED Alarm output
Default - Link not fitted JP17
Bypass active JP17 fitted
JP17 – Bypass Tone circuit 250Hz low pass filter
Tone- input JP22 fitted
DCS input JP22 removed
JP22 – (see also JP16) Tone input or DCS Digital Data Input
Position
1-2, 5-6 *
2-3, 4-5
Position
2-3 *
1-2
Position
open*
1-2
Position
1-2 *
open
JP16 –(see also JP22) DCS and low frequency Digital Data Input
Position
DCS Not selected JP16
1-2 *
Select DCS input JP16
2-3
THE FOLLOWING JUMPERS ARE VALID ON
TX PCB VERSION 30/9103/0009 OR LATER
Current Loop input
+12 Vdc Loop Source
JP9, JP10, JP11 dc Loop PTT Input Configuration (JP3 1-2)
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