Watkins-Johnson Company WJ-8718-19/FE Instruction Manual page 90

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WJ-8718-19/FE HF RECEIVER CIRCUIT DESCRIPTION
3.2.5.2 Input/Output Signal Interfaces
The following input/output signals interface with the Synthesizer Section:
a. 1 MHz REF IN - Rear panel Jll provides the input for a high
stability 1 MHz reference signal. Signal must be square wave
and TTL-compatible.
b. Tuning Data - BCD encoded data words are sent from the
Digital Control Section to program the output frequencies of
the 1st, 2nd, 3rd and BFO synthesizers.
c. 1st LO - The 1st LO output is provided as an input to the
RF/IF Conversion Section. Frequency range is 42.91-72.90 MHz
and level is +20 dBm nominal into 50 ohms.
d. 2nd LO - The 2nd LO output is provided as an input to the
RF/IF Conversion Section. Frequency range is 32.21000-
32.20001 MHz and level is 0 dBm nominal into 50 ohms.
e. 3rd LO - The 3rd LO output is provided as an input to the
IF/Demodulator Section. Frequency is fixed as 11.155 MHz and
level is -6 dBm nominal into 50 ohms.
f. BFO - The BFO output signal is provided as an input to the
IF/Demodulator Section. Frequency range is 447.1-463.9 kHz
and level is 40 mV rms (high impedance).
3.2.6 DIGITAL CONTROL SECTION
A General Discussion of the Digital Control Section functions and signal
interfaces is provided in the following paragraphs.
3.2.6.1 Digital Control Section Functions
The Digital Control Section performs the following functions:
a. Receiver Control - The Digital Control Section generates the
digital control words necessary to operate the RF/IF
Conversion, IF/Demodulator, and Synthesizer Sections.
b. Front Panel Interface - Operator selected parameter inputs are
interfaced from the front panel. to the digital circuitry to
generate receiver digital control words. Receiver status is also
input and displayed on the front panel displays and indicators
for monitoring purposes.
c. Remote Controller Interface - External controller commands are
interfaced to the digital circuitry to generate receiver digital
control words.
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