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2-2-3, ANTI-TRIP
The anti-trip circuits are a sub-system of the VOX system. The purpose is to keep the receiver audio generated by the
speaker from triggering the transmitter. A sample of the receiver audio is fed to the anti-trip circuit, processed and
presented as a negative dc voltage proportional to the amplitude of the audio sample. This signal inhibits the VOX
detector, V14C.
2-2-3-1 ANTI-TRIP TEST
Set up the transmitter in the safe mode. The anti-trip circuits are on all the time so the tests can be run without keying
up the transmitter.
Dynamic test.
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Connect the audio oscillator and the scope to high side of R103 (ANTI-TRIP).
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Connect the DVM to pin 1 of V14.
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Adjust the audio oscillator output to 1400HZ and 3vpp as measured on the scope. You should hear the tone in
the speaker in the power supply.
•
Rotate R103 from end to end monitoring the voltage on pin 1 of V14.
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At the counter-clockwise end the voltage should be -0.2vdc.
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At the fully clockwise end the voltage should be at least -34vdc.
Gain test.
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Adjust ANTI-TRIP control for 1vpp signal on pin 7 of V12.
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Voltage on pin 8 of V14 should be 38vpp
•
Voltage on pin 2 of V14 should be 100vpp
•
DC voltage on pin 1 of V14 should be 25vdc