8-17B: Time/Trigger/Synchronizer Circuits Flashcards
Transmitting Systems (4 cards)
8-17B2
The triggering section is also known as the:
A. PFN.
B. Timer circuit.
C. Blocking oscillator.
D. Synchronizer.
ANSWER D
The RADAR synchronizer is sometimes referred to as a timer or keyer, supplying the synchronizing singnal that time transmit pulses, indictor display, and many other curcuits in the receiver.
8-17B3
Operation of any RADAR system begins in the:
A. Triggering section.
B. Magnetron.
C. AFC.
D. PFN.
ANSWER A
The RADAR system MUST operate in the specific timed relationship, including the interval between transmitted pulses. Timing pulses relate to pulse repetition frequency, with additional RADAR components timed by the output of the sychronizer or by timing signals from the transmitter as it is turned on. This is the heart of a RADAR system, the triggering section sychronizer.
8-17B5
Pulse RADARs require precise timing for their operation. Which type circuit below might best be used to provide these accurate timing pulses?
A. Single-swing blocking oscillator
B. AFC controlled sinewave oscillator
C. Non-symmetrical astable multivibrator.
D. Triggered flip-flop type multivibrator
ANSWER A
The blocking oscillator operates for a perod of time, followed by a period of time where no oscillation occurs. The input then oscillates again. This oscilator is often used to form the pulse in a RADAR transmitter.
8-17B6
Unblanking pulses are produced by the timer circuit. Where are they sent?
A. IF amplifiers.
B. Mixer.
C. CRT.
D. Discriminator.
ANSWER C
The timer circuit determines pulse repetition rate and range markers, and provides blanking and unblanking signals for the cathode-ray tube in the raster scan display.
