Key Topic 14: Pulse Forming Networks Modulation

Question 1

8-14B1: The pulse developed by the modulator may have an amplitude greater than the supply voltage. This is possible by:

A. Using a voltage multiplier circuit.
B. Employing a resonant charging choke.
C. Discharging a capacitor through an inductor.
D. Discharging two capacitors in series and combining their charges.

Answer 1

B. Employing a resonant charging choke.

Question 2

8-14B2: Pulse transformers and pulse-forming networks are commonly used to shape the microwave energy burst RADAR transmitter. The switching devices most often used in such pulse-forming circuits are:

A. Power MOSFETS and Triacs.
B. Switching transistors.
C. Thyratrons and BJT’s
D. SCR’s and Thyratrons.

Answer 2

D. SCR’s and Thyratrons.

Question 3

8-14B3: The purpose of the pulse-forming network is to:

A. Determine the width of the modulating pulses.
B. Determine the pulse repetition rate.
C. Act as a high pass filter.
D. Act as a log pass filter.

Answer 3

A. Determine the width of the modulating pulses.

Question 4

8-14B4: The shape and duration of the high-voltage pulse delivered to the magnetron is established by:

A. An RC network in the keyer stage.
B. The duration of the modulator input trigger.
C. An artificial delay line.
D. The time required to saturate the pulse transformer.

Answer 4

C. An artificial delay line.

Question 5

8-14B5: Pulse-forming networks are usually composed of the following:

A. Series capacitors and shunt inductors.
B. Series inductors and shunt capacitors.
C. Resonant circuit with an inductor and capacitor.
D. None of the above.

Answer 5

B. Series inductors and shunt capacitors.

Question 6

8-14B6: An artificial transmission line is used for:

A. The transmission of RADAR pulses.
B. Testing the RADAR unit, when actual targets are not available.
C. Determining the shape and duration of pulses.
D. Testing the delay time for artificial targets.

Answer 6

C. Determining the shape and duration of pulses.