8-24C: Automatic Frequency Control/AFC

Question 1

8-24C5

A RADAR transmitter is operating on 3.0 GHz and the reflex klystron local oscillator, operating at 3.060 GHz, develops a 60 MHz IF. If the magnetron drifts higher in frequency, the AFC system must cause the klystron repeller plate to become:

A. More positive.
B. More negative.
C. Less positive.
D. Less negative.

Answer 1

ANSWER B
The reflector is also called a repeller plate. It is negatively charged to repel the electrons. The more negatively charged the repeller plate, the lower the klystron frequency. The drift is high so the repeller must be more negative.

Question 2

8-24C6

What component is block 50?

A. IF amplifier.
B. AFC amplifier.
C. Discriminator.
D. Crystal detector.

Answer 2

ANSWER C
Block 50 is the discriminator stage and is fed by the intermediate frequency amplifier and its output is to the output AFC circuit.