摘要 |
The output frequency of a variable frequency oscillator is compared with that of a reference frequency source by means of a phase detector and the resultant error signal is integrated and applied as a negative feedback signal to the input of the oscillator whereby drift of the oscillator output frequency is minimized. Deviation, modulation index, dynamic stability and linearity are enhanced by means of a pulse generator that is synchronized with a modulating input signal supplied to the oscillator for supplying a keying signal to the phase detector during a portion of each cycle of the modulating input signal.
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