FCC Exam Question: 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:
Explanation: Video amplifiers require a wide bandwidth to accurately reproduce high-speed video pulses. Internal and parasitic capacitances at the input and output stages naturally limit the amplifier's high-frequency response, causing distortion like rounded edges in pulses. To counteract this: * **At the input:** An inductor connected *in series* with the signal path, effectively before the input capacitance, creates a series resonant circuit. At higher frequencies, this series peaking boosts the signal, compensating for the input capacitance's tendency to roll off the high frequencies. * **At the output:** An inductor connected *in parallel* with the output capacitance forms a parallel resonant circuit. At the target high frequencies, this parallel (shunt) peaking provides a high impedance, preventing the output capacitance from shunting the signal to ground and maintaining the amplifier's gain. This combination (series inductor at input, parallel inductor at output) is a standard technique for broadband amplifier compensation, extending the frequency response and preventing pulse distortion. Options A, B, and C either use incorrect components (resistances) or incorrect inductor placements for effective compensation.
8-5A5
8-50F6
8-26C2
8-42E4
8-5A1
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Includes Elements 1, 3, 6, 7R, 8, and 9.