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سؤال 436

What is a phase-locked loop?

  1. An electronic servo loop consisting of a ratio detector, reactance modulator, and voltage-controlled oscillator
  2. An electronic circuit also known as a monostable multivibrator
  3. An electronic servo loop consisting of a phase detector, a low-pass filter, a voltage-controlled oscillator, and a stable reference oscillatorپاسخ درست
  4. An electronic circuit consisting of a precision push-pull amplifier with a differential phase input

توضیح

A phase-locked loop is a servo loop: a phase detector compares a stable reference with the output of a voltage-controlled oscillator, and the resulting error, after smoothing, tunes the VCO until the two stay locked in phase.

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شروع تمرین
سؤال 436: What is a phase-locked loop? · FCC Amateur Extra Class (Element 4) · Questena