Self-tuning receiver/decoder for frequency shift keying RF data transmission
First Claim
1. A self-tuning receiver/decoder for reception of frequency shift-keying RF data transmission, including a radio frequency stage comprising resonant circuit means for being tuned to a first frequency of a plurality of more than two other frequencies for reception of such frequencies according to interrogation at such frequencies in sequence, means for detecting each frequency shift change of such interrogation frequency to a subsequent one of the other frequencies, and means for retuning the resonant circuit for reception of each of such other frequencies whereby to generate frequency shift data bit signals in a format identical to a frequency shift-keying RF format received.
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Accused Products
Abstract
A self-tuning receiver/decoder for reception of FSK data transmission. An RF stage with resonant circuit (10) is tuned to a first of four possible transmitted frequencies for reception of such frequencies according to interrogation at such frequencies in sequence. Threshold (18) and counter circuits (12, 16) detect each frequency shift change of transmitted frequency and accordingly retune the resonant circuit to a subsequent unknown frequency by counting through a predetermined sequence for possible reception of each of such frequencies. Provision (24) is made for latching frequency shift data bit signals accordingly as output in a format identical to the frequency shift-keying RF format received. The receiver/decoder is especially useful for miniaturized transponder operation in which it alternates between receiving and transmitting modes, and is powered by capacitively stored charge in response to continuous transmission of the first frequency over a period.
82 Citations
16 Claims
- 1. A self-tuning receiver/decoder for reception of frequency shift-keying RF data transmission, including a radio frequency stage comprising resonant circuit means for being tuned to a first frequency of a plurality of more than two other frequencies for reception of such frequencies according to interrogation at such frequencies in sequence, means for detecting each frequency shift change of such interrogation frequency to a subsequent one of the other frequencies, and means for retuning the resonant circuit for reception of each of such other frequencies whereby to generate frequency shift data bit signals in a format identical to a frequency shift-keying RF format received.
Specification