| 摘要 |
The invention provides a frequency generator capable of producing an output frequency which is continuously variable but which is nevertheless phase-locked to a stable reference frequency. The output frequency is derived from a V.C.O., and is sampled at the reference frequency to produce a difference frequency equal to the difference between the output frequency and a harmonic of the reference frequency. This difference frequency is maintained equal to another reference frequency, lower than the first, by comparison with this other reference frequency in a phase-sensitive detector, whose output is applied to the V.C.O. to complete a phase-locked loop.
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