Low power RF receiver
First Claim
1. A low power RF receiver for receiving a modulated carrier signal having a coded transmission so as to remotely control a number of vehicular devices comprising:
- input means responsive to said modulated carrier signal for generating a RF signal;
oscillator means for generating a desired local oscillator frequency signal;
mixer means responsive to said RF signal and said local oscillator frequency signal for generating an IF signal;
first filter means responsive to said IF signal for generating a first filtered signal;
first FI amplifier means responsive to said first filtered signal for generating a first amplified signal;
second filter means responsive to said first amplified signal for generating a second filtered signal;
second IF amplifier means responsive to said second filtered signal for generating a second amplified signal;
signal strength means connected to said first and second IF amplifier means and responsive to the amount of current drawn by said first and second IF amplifier means, said signal strength means generating a strength indicator signal derived form assumed current of the first and second amplified signal which is proportional to the strength of the modulated carrier signal received by said input means; and
adaptive threshold means being responsive to comparing said strength indicator signal to a varied threshold reference level to eliminate noise and for generating a logical signal based on said comparison of said varied threshold reference level to said strength indicator signal.
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0 Petitions
Accused Products
Abstract
A low powered RF receiver for receiving a modulated carrier having a coded transmission so as to remotely control a number of vehicular devices includes an antenna, a preamp stage, mixer, local oscillator, first and second IF bandpass filters, first and second IF amplifiers, a received signal strength indicator/detector circuit, and an adaptive threshold/filter circuitry. The signal strength indicator/detector circuit is interconnected between the first and second IF amplifiers and generates a strength indicator signal which is proportional to the strength of the modulated carrier signal received. The adaptive threshold/filter circuitry is responsive to the strength indicator signal and has a varied threshold reference level for eliminating noise and for converting the strength indicator signal to a logical level. A microcontroller is provided for further signal processing, decoding, and executing the function corresponding to the vehicular device to be controlled.
103 Citations
20 Claims
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1. A low power RF receiver for receiving a modulated carrier signal having a coded transmission so as to remotely control a number of vehicular devices comprising:
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input means responsive to said modulated carrier signal for generating a RF signal; oscillator means for generating a desired local oscillator frequency signal; mixer means responsive to said RF signal and said local oscillator frequency signal for generating an IF signal; first filter means responsive to said IF signal for generating a first filtered signal; first FI amplifier means responsive to said first filtered signal for generating a first amplified signal; second filter means responsive to said first amplified signal for generating a second filtered signal; second IF amplifier means responsive to said second filtered signal for generating a second amplified signal; signal strength means connected to said first and second IF amplifier means and responsive to the amount of current drawn by said first and second IF amplifier means, said signal strength means generating a strength indicator signal derived form assumed current of the first and second amplified signal which is proportional to the strength of the modulated carrier signal received by said input means; and adaptive threshold means being responsive to comparing said strength indicator signal to a varied threshold reference level to eliminate noise and for generating a logical signal based on said comparison of said varied threshold reference level to said strength indicator signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A low power RF receiver for receiving a modulated carrier signal having a coded transmission so as to remotely control a number of vehicular devices comprising:
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input means responsive to said modulated carrier signal for generating a RF signal; oscillator means for generating a desired local oscillator frequency signal; mixer means responsive to said RF signal and said local oscillator frequency signal for generating an IF signal; first filter means responsive to said IF signal for generating a first filtered signal; first IF amplifier means responsive to said first filtered signal for generating a first amplified signal; second filter means responsive to said first amplified signal for generating a second filtered signal; second IF amplifier means responsive to said second filtered signal for generating a second amplified signal; signal strength means connected to said first and second IF amplifier means and responsive to the amount of current drawn by said first and second IF amplifier means, said signal strength means generating a strength indicator signal derived form a summed current of the first and second amplified signals which is proportional to the strength of the modulated carrier signal received by said input means; adaptive threshold means being responsive to comparing said strength indicator signal to a varied threshold reference level to eliminate noise and for generating a logical signal based on said comparison of said varied threshold reference level to said strength indicator signal; and microcontroller means for processing said logical signal containing a series of coded pulses defining functions relating to said received modulated carrier signal, said functions defining operations to control the vehicular devices. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification