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Abstract

A universal garage door opener (UGDO) that records and recreates a carrier frequency signal from a wide range of commercially available garage door openers. A receiver portion of the UGDO includes a detector for removing a carrier wave of the received carrier frequency signal. The carrier frequency signal is applied to a frequency synthesizer including a dual modulus prescaler divider chain. The carrier frequency signal is divided down by the divider chain and compared to a divided reference frequency signal to determine the carrier frequency. The dual modulus divider chain starts at a maximum divide ratio, and periodically changes the divide ratio until the divided carrier frequency signal is within a predetermined resolution range of the divided reference frequency signal. A JK flip flop is used to hold a phase detect output signal of the frequency synthesizer indicative of the divided carrier frequency signal. A carrier frequency signal from a variable controlled oscillator is applied to the frequency synthesizer to be divided down by the dual modulus prescaler divider chain. The phase detect output signal from the frequency synthesizer is used to adjust the center frequency of the VCO so that the divided VCO frequency signal conforms to the original carrier frequency signal. The output carrier frequency of the VCO is also applied to an amplifier that is responsive to a modulation signal to modulate the carrier frequency in accordance with the originally stored demodulation signal from the carrier frequency signal.

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First Claim