Telecommunications – Receiver or analog modulated signal frequency converter – Local control of receiver operation
Patent
1981-04-23
1982-09-28
Chin, Tommy P.
Telecommunications
Receiver or analog modulated signal frequency converter
Local control of receiver operation
455168, H03J 308, H04B 116
Patent
active
043522084
ABSTRACT:
A microprocessor controlled radio receiver system for switching bandwidths of an intermediate frequency stage from a normally scanning mode using a relatively narrow bandwidth to a second mode using a relatively wide bandwidth automatically when there are no interfering signals from adjacent channels of a channel or station selected for receiving. Upon selection of a channel for listening the microprocessor controlled synthesizer causes the synthesizer to scan up one adjacent channel and down one adjacent channel to determine if there is an interfering signal therefrom and then returns to the selected channel. In the event of no interfering signal from an adjacent channel, switching is effected in the IF stage from a narrow bandwidth to a wide bandwidth to improve the quality of reception. If there is an adjacent channel signal detected of sufficient IF energy next to the selected channel, then the narrow bandwidth mode used during the scan will be maintained.
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Digital Television Tuner Uses MOS LSI and Nonvolatile Memory, by Penner, Electronics, Apr. 1, 1976, pp. 86-90.
Voltage Synthesized Electronic Tuning System LSI for AM/FM Radio, by Ikeguchi, IEEE Transactions on Consumer Electronics, vol. CE-25, Aug. 1979, pp. 621-626.
Technics ST-9030 Tuner, Audio Magazine, Jul. 1979.
National Semiconductor Combined Engineering and Application Note for Part No. DS8907 AM/FM Digital Phase-Locked Loop Frequency Synthesizer.
Chin Tommy P.
Gillman James W.
Motorola Inc.
Pristelski James S.
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