Browse Prior Art Database

Tone Encoder and Pocket Pager

IP.com Disclosure Number: IPCOM000077106D
Original Publication Date: 1972-Jun-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 44K

Publishing Venue

IBM

Related People

Hamilton, RJ: AUTHOR

Abstract

An inexpensive tone encoder and pocket paging receiver use common commercial components.

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Tone Encoder and Pocket Pager

An inexpensive tone encoder and pocket paging receiver use common commercial components.

In Fig. 1, the tone encoder supplies a two-tone sequential page to any commercial VHF communications transmitter. Two single-shots provide the basic timing pulses which are logically combined to provide gating pulses for the tones and a control pulse for the transmitter. The audio tones are generated by oscillators and gated to the output buss in the proper sequence and duration.

In Fig. 2, the pocket pager is a single conversion narrow-band frequency modulation receiver with integral tone decoding for a two-tone sequential page. The unit is crystal controlled and operates in the VHF public service band. The front end of the receiver consists of a FET RF amplifier, a FET mixer, and a crystal oscillator which provide a 10.7 Mhz IF signal. IF amplification is performed by an NES10A integrated circuit manufactured by Signetics Corporation. Demodulation utilizes an NES61B phase-locked loop integrated circuit. The demodulated signal feeds two NES67T phase-locked loop integrated circuits with frequency and timing components selected to decode the desired page. Once the page is decoded, a latch is set gating the demodulated output through squelch circuitry and a CA3020 integrated circuit amplifier manufactured by the Radio Corporation of America for the reception of voice transmissions.

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