Showing papers on "Comb generator published in 1974"

Frequency division multiplex system using comb filters

Abstract: Disclosed herein is a novel frequency division multiplex system for use in connection with transient signals such as speech and music signals. One embodiment includes a pair of comb filters, the response characteristics of which are staggered so that the pass bands of one comb filter are in alignment with the attenuation bands of the other comb filter. Each channel signal is filtered by its associated comb filter and then combined to develop a comb frequency division duplex (CFDD) signal for transmission over a transmission medium. At the receiving terminal the CFDD signal is decombined into the individual channels and passed through another pair of comb filters, the response characteristic of each comb filter being the same as that of the comb filter in a corresponding input channel. In another embodiment, a recording and playback system is provided to record the CFDD signal, i.e., two channels of information in a single track on disc or tape and to playback such recorded information. This invention is based on the observation that the attenuation of some of the frequencies in audio signals does not materially degrade the naturalness and intelligibility of the signals.

Double comb filter

Abstract: A first comb filter is employed to eliminate the chrominance subcarrier from a composite video signal containing chrominance information. The resultant signal contains certain undesired signals. These are cancelled by using a second comb filter to comb out the chrominance subcarrier from the signal from the delay line of the first comb filter leaving the undesired signals which are then added to the output signal of the first comb filter. The undesired signals cancel because they are in phase opposition.