8-23C: Detectors

Question 1

8-23C3

In video amplifiers, compensation for the input and output stage capacitances must be accomplished to prevent distorting the video pulses. This compensation is normally accomplished by connecting:

A. Inductors in parallel with both the input and output capacitances.
B. Resistances in parallel with both the input and output capacitances.
C. An inductor in parallel with the input capacitance and an inductor in series with the output capacitance.
D. An inductor in series with the input capacitance and an inductor in parallel with the output capacitance.

Answer 1

ANSWER D
Avideo amplifier must amplify a wide band of frequencies with minimal frequency and phase distortion. Parasitic capacitance at the input and output of any amplifier can limit the bandwidth and cause undesireable phase shift, which can distort the shape or size of any detected RADAR pulse. These parasitic capacitances can be compensated for by the use of proper complementary inductances. The most troublesome parasitic capacitances of any active device are input series capacitnce and output parallel capacitance. The input series capacitance can be compensated for by an input series inductance, and the output parallel capacitance can be compensated for wich a parallel inductance.

Question 2

8-23C6

The video (second) detector in a pulse modulated RADAR system would most likely use a/an:

A. Discriminator detector.
B. Diode detector.
C. Ratio detector.
D. Infinite impedance detector.

Answer 2

ANSWER B
A crystal detector diode is most often used to extract the video modulation from the carrier.