Showing papers on "Comb generator published in 1969"

Fm receiver self-test circuit

Abstract: A self-testing equipment for a frequency-modulated receiver includes a pulse generator rich in harmonics and having a repetition frequency chosen such that the fundamental frequency is substantially equal to the channel spacing of the FM receiver being tested. The supply voltage for the pulse generator is derived from a power supply generator which produces a pulsating voltage varying periodically at a relatively slow rate. This voltage is applied to the pulse generator and serves to modulate the frequency of the pulse generator at the same rate. The accompanying harmonics of the pulse generator are also modulated but at a correspondingly high rate lying within the audio bandwidths of each receiver channel. Inserted between the power supply generator and the pulse generator is a time constant network which permits the supply voltage to vary exponentially during each power supply period. In this way, the frequency deviation of the pulse generator is controlled.