Title: Automatic control system for condition-responsively switching over transceiver and radio or tape recorder audio signals

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Claims: What is claimed is:

1. Automatic signal switching apparatus for interrupting the reproduction of audio signals from a source during the receipt of signals from a transceiver and reproducing the transceiver signals comprising signal reproducing means, a first amplifying transistor connected to said source to said reproducing means for feeding signals from said source to said reproducing means, a second amplifying transistor connected to said transceiver and to said reproducing means, a squelch control transistor having a base and emitter and collector electrodes, means applying a potential between the emitter and collector of said control transistor, means coupling the base of said control transistor to said transceiver to modify conductivity of said transistor upon receipt of a transceiver signal and produce a potential change of a least one of said electrodes, means couling the last said electrode to said first amplifying transistor to inactivate it upon the occurrence of said potential change and terminate the reproduction of said source signals and means coupling the last said electrode to said second amplifying transistor to activate it and feed said transceiver signals to said reproducing means whereby signals from said source will be reproduced during the absence of a transceiver signal and will be interrupted during the presence of a transceiver signal.

2. Automatic signal switching apparatus according to claim 1 including a time constant network interconnected with said control transistor to delay the reproduction of said source signals for a preselected period of time upon termination of said transceiver signals.

Other info:

Inventors: Arai, Kazuo (Kitamoto, JA)

Application Number: 556491
Filing Date: 1975-03-07
Publication_date: 1976-07-27
Assignee: Nissan Denshi Company Limited (Ohmiya, JA)
Primary Class(es): 455/88 455/133
Other Classes:
US Patent Ref:

3277374	Oct, 1966	Kobayashi	325/18.
3745467	Jul, 1973	Lundquist et al.	325/304.

Other Refs:
Primary Examiner: Safourek, Benedict V.
Assistant Examiner:
Attorney: Graham; Thomas B.