Marti Electronics SRPT-30 User Manual page 38

FRONT PANEL CONTROL & METER Board, 800-389A (800-382A – some models) –
SRPT-30 only
This board does the following:
- Sends F1/F2 state to TRANSMITTER SYNTHESIZER,
- Displays LED alarm information received from the TRANSMITTER SYNTHESIZER,
- Receives and decodes digital data from TRANSMITTER SYNTHESIZER for forward and reverse power
readings and converts to analog signals,
- Directs POWER ADJUST analog signal to TRANSMITTER SYNTHESIZER,
- Multiplexes all analog metering signals via METER SELECT knob for independently monitoring on METER,
- Sends state of the TRANSMIT/STANDBY switch.
FRONT PANEL CONTROL & METER Board, 800-385A (800-378A – some models) –
SRPT-40A only
This board does the following:
- Collects and sends commands from the front panel pushwheel switches to the on-board microcontroller of the
TRANSMITTER SYNTHESIZER board,
- Displays LED alarm information received from the TRANSMITTER SYNTHESIZER,
- Receives and decodes digital data from TRANSMITTER SYNTHESIZER for forward and reverse power
readings and converts to analog signals,
- Directs POWER ADJUST analog signal to TRANSMITTER SYNTHESIZER,
- Multiplexes all analog metering signals via METER SELECT knob for independently monitoring on METER,
- Sends state of the TRANSMIT/STANDBY switch.
TWO-STAGE RF POWER AMPLIFIER Board, 800-388A (800-373A – some models)
The RF output signal (50 mW max) from the TRANSMITTER SYNTHESIZER is fed into this TWO-STAGE RF
POWER AMPLIFIER board. The RF goes through two stages of RF amplification. The first stage (U2) is a 1-Watt
(max) pre-driver. It has an input and output transformer (T1 and T2) for achieving optimum 50 Ohm matching between
the stages. The output of T2 is fed into the final PA module (U3) for an output of up to 60 Watts max. This PA module
usually has a lower RF output for SRPT-30's. The signal is then low-passed filtered through FL1 and then fed through a
directional coupler for monitoring forward and reflected power. An Automatic Power Control (APC) circuit residing on
the TRANSMITTER SYNTHESIZER board stabilizes and maintains an accurate output power level by comparing it to
a reference power level which is set by the user via the front panel POWER ADJUST pot. The APC circuit samples the
forward power via the coupled forward power on PA board.
This board also provides regulated B+ for powering the PA and the rest of the chassis when using 15-30 Volts
external supply. Finally, there also exist circuitry for regulating the fan, measuring PA temperature, and monitoring PA
current.
SWITCHING POWER SUPPLY, 800-383A (800-324A – some models)
The Switching Power Supply accepts input from 110-120 or 220-240 VAC and supplies 15 VDC and up to 10
Amperes to power the SRPT-30/40A. The power supply must be switched to the appropriate 115 or 230 position. This is
usually done at the factory.
RPU TRANSMITTER I/O Board, 800-379AR
This board passes and distributes external power supply input via the back-panel ACCESSORY connector. It also
passes and directs the ENCODE, TX REM CNTL, and external audio signals. All signals are LC filtered.
8/7/2003
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