DRAKE MMTS20 manual
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8 WARRANTY AND SPECIFICATIONS
R.L. DRAKE COMPANY warrants to the original purchaser this product shall be free from defects in material or workmanship for three (3) years from the date of original purchase.
During the warranty period the R.L. DRAKE COMPANY or an authorized Drake service facility will provide, free of charge, both parts and labor necessary to correct defects in material and workmanship. At its option, R.L. DRAKE COMPANY may replace a defective unit.
To obtain such warranty service, the original purchaser must: of:
(a) the model and serial number,
(b) the identity of the seller and the approximate date of purchase; and
(c) A detailed description of the problem, including details on the electrical connection to associated equipment and the list of such equipment.
or equivalent, fully insured and shipping charges prepaid.
Correct maintenance, repair, and use are necessary to obtain proper performance from this product. Therefore carefully read the Instruction
Manual. This warranty does not apply to any defect that R.L. DRAKE COMPANY determines is due to: of the original parts.
All implied warranties, if any, including warranties of merchantability and fitness for a particular purpose, terminate three (3) years from the date of the original purchase.
The foregoing constitutes R.L. DRAKE COMPANY’S entire obligation with respect to this product, and the original purchaser shall have no other remedy and no claim for incidental or consequential damages, losses or expenses. Some states do not allow limitations on how long an implied warranty lasts or do not allow the exclusions or limitation of incidental or consequential damages, so the above limitation and exclusion may not apply to you.
This warranty gives you specific legal rights and you may also have other rights which vary from state to state. This warranty shall be construed under the laws of Ohio.
®
R.L. DRAKE COMPANY
230 INDUSTRIAL DRIVE
FRANKLIN, OHIO 45005 U.S.A.
CUSTOMER SERVICE AND PARTS TELEPHONE:
+1 (937) 746-6990
TELEFAX:
+1 (937) 743-4576
WORLD WIDE WEB SITE: http://www.rldrake.com
®
MMTS20 STEREO ENCODER 1
12 POSITION RACK UNIT POWER SUPPLY
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CH
AUDIO
VIDEO
PWR
A / V
RF
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AUDIO
VIDEO
PWR
A / V
RF
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AUDIO
VIDEO
PWR
A / V
RF
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AUDIO
VIDEO
PWR
A / V
RF
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AUDIO
VIDEO
PWR
A / V
RF
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AUDIO
VIDEO
PWR
A / V
RF
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CH
AUDIO
VIDEO
PWR
A / V
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AUDIO
VIDEO
PWR
A / V
RF
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CH
AUD IO
MMTS20
O N
OF F
POWER
PILOT
LOCK
TEST
TO NE
OVER-
MOD
AUDIO LEVEL
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CH
AUDIO
VIDEO
PWR
A / V
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AUDIO
VIDEO
PWR
A / V
RF
RF
4 POSITION
RACK UNIT
OR MMTS20 and other compatible modular units
POWER SUPPLY
POWER SUPPLY
RMM4
The R.L. Drake MMTS20 is an MTS stereo encoder which accepts left and right channel audio input and generates a composite BTSC format stereo signal. The composite signal is applied to the audio input of a compatible audio/video modulator. The modular design of the MMTS20 permits convenient pairing with a
Drake Mini-rack fixed channel or agile type
Video Modulator in a multiple unit rack configuration.
Rear panel left and right audio inputs allow either balanced or unbalanced operation. The
MMTS20 must be supplied with the modulator video in order to provide the MMTS20 with sync information for the encoding process. A front panel Audio Level control with corresponding
Overmodulation indicator permits setting the proper audio input levels to the MMTS20.
A Pilot Lock indicator is provided to verify that the encoder is properly synchronized to the supplied video horizontal sync. A built-in audio test tone generator, turned on or off from a front panel switch, is provided for calibration of the modulator Audio Input level.
As previously described, front panel controls include Audio Level and Test Tone switch. Front panel indicators are Power, Pilot Lock, and
Overmodulation. A rear panel 'F' type connector is provided for the video sync reference.
Left and right audio inputs are through rear panel 3.5 mm 'stereo' type receptacles. The composite BTSC signal output is through a rear panel RCA type phono connector. The unit is powered by a compatible Drake Mini-rack power supply module.
® is a registered trademark of the R.L. Drake Company
© Copyright 2001 R.L. Drake Company P/N: 3852478D-10-2001 Printed in U.S.A.
2 FRONT PANEL CONTROLS and INDICATORS
F1
F2
F3
F4
F5
MMTS20
ON
OFF
STEREO
ENCODER
POWER
PILOT
LOCK
TEST
TONE
OVER-
MOD
AUDIO LEVEL
Figure 1
F1 - POWER Indicator
Lights when the unit is connected to the required source of DC power.
F2 - PILOT LOCK Indicator
Lights to indicate that a video signal is applied to the rear panel VIDEO INPUT connector and that the MMTS20 is locked to the video horizontal sync.
F3 - TEST TONE Switch
Switch to the 'ON' position to enable an internal test tone to aid system audio level setup. See the 'Installation' section of this manual for setup information. The normal position of this switch is the 'OFF' position.
F4 - OVERMODULATION Indicator
Lights to indicate greater than 25 kHz of main channel deviation. After system audio modulation levels are properly set, and with left and right audio source input, adjust the AUDIO
LEVEL control (see item F5) to a point where the OVERMODULATION indicator just remains off.
F5 - AUDIO LEVEL Control
The setting of this screwdriver adjustment determines the audio input signal level. After system audio modulation levels are properly set, and with left and right audio signals within the 250 mVrms to 2.5 V rms range, set this control to a point where the
OVERMODULATION indicator just remains off
(see item F4).
SPECIFICATIONS 7
AUDIO INPUT
Input Impedance:
Input Level:
40 K Ohms balanced,
20 K Ohms unbalanced.
250 mVrms to 2.5 V, front panel adjustment.
VIDEO INPUT
Input Impedance:
Input Level Range:
High impedance, intended to be paralleled with paired
A/V modulator unit.
Input Level Range: 0.5 Vp-p to 2 Vp-p.
COMPOSITE OUTPUT
Output Impedance:
Output Level:
100 Ohms, intended to drive high impedance audio input of paired A/V modulator.
10 mV/kHz, ±10%.
1.1 Vp-p for a 100% modulation signal.
STEREO PERFORMANCE
Stereo Separation:
Total Harmonic Distortion:
S/N Ratio:
Frequency Response:
Spurious Subcarrier:
NOTE:
Greater than 20 dB.
Less than .25%.
Greater than 65 dB.
Within ±1 dB from 40 Hz to 12.5 kHz.
-50 dBc typical.
System performance is dependant upon paired modulator.
TEST TONE
Frequency:
Amplitude:
10.396 kHz ±50 Hz.
0.5 Vp-p ±10%; all output levels are calibrated to the level of this tone and is used to set system audio levels for proper stereo operation. The paired A/V modulator audio response must be set for “Flat”
(pre-emphasis defeated).
GENERAL
DC Power Input:
Operating Temperature Range:
Size:
Weight:
+12 V ±5% @ 150 mA
(+5 V is not required for this unit).
0 0 C to +50 0 C ambient.
1” W x 3.5” H x 7.5” D
(2.5 cm) W x (8.9 cm) H x (19.1 cm) D.
10.7 oz. (0.3 Kg).
Specifications subject to change without notice or obligation.
6 INSTALLATION - AUDIO LEVEL SETTING, continued
4) Set the MMTS20 'TEST TONE' switch to the
'OFF' position. Connect Left and Right audio source signals to the MMTS20.
The system audio levels are now properly set.
Disconnect the test equipment.
5) Set the 'Audio LEVEL' control on the
MMTS20 to a point where the
'OVERMODULATION' indicator just remains off or flashes occasionally.
METHOD 2: (If a spectrum analyzer is not available).
1) Connect the MMTS20, A/V modulator, compatible DC power source, and video source signal as shown on this page. Keep the 'TEST
TONE' switch 'OFF' for this procedure.
2) Connect a TV receiver (with MTS stereo capability) to the A/V modulator. Tune the TV receiver to the same channel as the modulator output.
NOTE: Make certain that the audio response of the A/V modulator is set for 'FLAT'
(pre-emphasis defeated).
3) Connect the audio source signal (not a tone) to either the LEFT or the RIGHT Audio Input of the MMTS20.
4) Set the 'Audio LEVEL' control on the
MMTS20 to a point where the
'OVERMODULATION' indicator just remains off or flashes occasionally.
5) While monitoring the opposite audio channel from the TV receiver audio output, set the
'Audio' level control on the A/V modulator for a maximum (stereo) separation condition.
Video Source
REAR PANEL CONNECTIONS / INTERNAL JUMPERS 3
R3
R4
R1
R2
Figure 2
R1 - VIDEO INPUT Connector
This is the baseband video input to the
MMTS20 which provides the encoder circuitry with the modulator horizontal sync information.
The baseband video to the modulator must be
'looped through' this input using an external 'F' type Tee (T) connector.
R2 - COMPOSITE AUDIO OUT Connector
This is the unbalanced composite BTSC format stereo signal output. The output from this RCA phono receptacle must be connected to the
AUDIO INPUT of the modulator. The connected modulator audio response must be set for 'Flat'
(pre-emphasis defeated).
R3 - DC INPUT Connector
This 3-pin connector (Male) accepts the appropriate mating DC power cable. Observe proper orientation and wiring.
R4 - LEFT AUDIO INPUT/RIGHT AUDIO
INPUT Connectors
These are the left and right audio source input connectors that accept either a balanced or unbalanced configuration. Use the Tip (+) and
Ring (-) of a mating male 3.5 mm ‘stereo’ plug for a balanced connection. If an unbalanced input is required, the Ring (-) contact should be connected to ground (shield) with the audio hot connected to the Tip (+).
MMTS20
ON
OFF
STEREO
ENCODER
POWER
PILOT
LOCK
TEST
TONE
OVER-
MOD
AUDIO LEVEL
Video Input
Loop-Through
Composite
Audio Out
DC Input
Audio
Cable
DC Input
Video Input
Audio Input
Audio
In
MMTS20 FRONT MMTS20 REAR
Right audio source
Left audio source
(250 mV rms to 2.5 V rms)
To
System Distribution or
A/V MODULATOR
TV Receiver
4 INSTALLATION
CONNECTIONS AND CONTROLS
All connections to and from each modulator are made through the rear panel. Figure 3 illustrates an installation with (11) modulator units combined through a passive signal combiner. Additional channels can be added by using additional fixed channel or agile type modulators and either multi-port combiners or combinations of two-port combiners.
INSTALLATION NOTES
Level adjustment provides optimum performance in multichannel installations.
The modulator outputs should be checked periodically with a spectrum analyzer to
VIDEO INPUT maintain a ±1 dB variation of adjacent channel carriers. Aural/Visual (A/V) ratios should be held to -15 dB or less. The output ‘RF’ and ‘A/V
(Ratio)’ controls are used respectively to make these adjustments.
RACK MOUNTING
Adequate ventilation is very important in multichannel installations. Some air movement is mandatory in enclosed rack cabinets.
Excessive heat will shorten component life and modulator performance will be degraded without proper cooling.
AUDIO IN
RIGHT LEFT
MMTS20
STEREO
ENCODER
To Video Input of MMTS20
To Video Input of
Video Modulator
MODULATOR UNIT
(Fixed channel and/or Agile type audio response set for "Flat")
AC POWER
CORD
DC POWER
CABLE
Video Source
INSTALLATION - AUDIO LEVEL SETTINGS 5
METHOD 1:
Connect the MMTS20, Audio/Video Modulator, compatible DC power source, video source signal and test equipment as shown.
Make certain that the audio response of the A/V modulator is set for 'FLAT' (pre-emphasis defeated).
Video Input
Loop-Through
Composite
Audio Out
DC Input
Left Audio In
Right Audio In
Audio
Cable
DC Input
Coaxial Cable
SPECTRUM
ANALYZER
MMTS20
REAR PANEL
A/V
MODULATOR
1) Set the 'Test Tone' switch on the front panel of the MMTS20 to the 'ON' position.
ON
OFF
PILOT
LOCK
TEST
TONE
3) Adjust the 'Audio Level' control on the front panel of the connected A/V modulator for a setting that nulls the aural carrier. If more than one null is found, use the lowest audio gain setting that produces a null of the aural carrier.
2) Using the connected spectrum analyzer, tune the aural carrier to the center of the screen.
Spectrum Analyzer Settings:
SPAN: 100 kHz.
Res BW: 1 kHz.
SWEEP: 300 mSec.
VBW: 1 kHz.
MODULATOR
AUDIO
VIDEO
Aural Carrier Null
RF COMBINER
SYSTEM OUT
Figure 3
Aural Carrier Centered

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