-- card: 28465 from stack: in
-- bmap block id: 0
-- flags: 4000
-- background id: 7720
-- name: #266
----- HyperTalk script -----
on openCard
  global group,rightone
  put 27 into group
  put "B" into rightone
  pass openCard
end openCard



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Question #27

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4BF-3.3 A circuit compares the output from a voltage-controlled oscillator and a frequency standard.  The difference between the two frequencies produces an error voltage that changes the voltage-controlled oscillator frequency.  What is the name of the circuit?

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A doubly balanced mixer

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A phase-locked loop

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A differential voltage amplifier

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A variable frequency oscillator

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Correct answer is B