Title: Multi-frequency signal receiver

Abstract: A multi-frequency signal receiver for use in tone signalling circuits is disclosed. The receiver includes a plurality of channel band pass filters having mutually independent pass bands, each of which receives the input signal. Threshold detectors are connected to the outputs of the channel bandpass filters as is a variable threshold circuit. The variable threshold circuit includes a peak hold circuit and an attenuator for generating a threshold value for the detectors. A rectifier and integrator circuit rectifies an output which is weighted compared with the output of the peak hold circuit to produce a timing signal. The timing signal is used to gate the output of the detectors.

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Inventors: Hasegawa, Kouichi (Tokyo, JP)

Application Number: 871711
Filing Date: 1978-01-23
Publication_date: 1979-03-20
Assignee: Nippon Electric Co., Ltd. (Tokyo, JP)
Primary Class(es): 340/825.73
Other Classes:
US Patent Ref:

3961143

Jun, 1976

Thyssens

179/84.

Other Refs:
Primary Examiner: Cooper, William C.
Assistant Examiner:
Attorney: Sughrue, Rothwell, Mion, Zinn and Macpeak