Trio Electronics Incorporated

Kaoru Mitarai

Mitsuo Matsuzawa

A station selecting system for use in a multi-channel communication system having a plurality of display devices respectively corresponding to the communication channel. Circuitry is provided for placing the system in a monitor mode of operation where all channels are scanned once to determine which ones are available for communication, the latter channels being indicated by actuation of the display devices respectively corresponding thereto. Circuitry is also provided for placing the system in an autoscan mode of operation where the channels are sequentially scanned until a channel available for communication is located, at which time scanning ceases and the selected channel is indicated by the actuation of its corresponding display device.

Station selecting device having improved monitor

A multi-channel communication system including automatic station selecting circuitry and circuitry for preventing actuation of the station selection circuitry by noise or the like. The station selecting circuitry automatically, sequentially generates a plurality of local oscillator signals which are mixed with incoming information signals transmitted in one or more of the channels of the system. Whenever the frequency difference between an information signal and a local oscillator signal falls within the pass band of the receiving channel, a sensing signal is generated which stops the automatic station selector so that communications can occur on the selected channel. Circuitry is also employed to discriminate between noise and an appropriate information signal in the receiving channel so that the above-mentioned sensing signals are generated only when information signals are present.

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Tokyo, Japan

Kaoru Mitarai