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Trainable transceiver including a dynamically tunable antenna

  • US 5,699,054 A
  • Filed: 05/19/1995
  • Issued: 12/16/1997
  • Est. Priority Date: 05/19/1995
  • Status: Expired due to Term
First Claim
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1. A trainable transceiver for receiving an activation signal that includes a radio frequency carrier modulated with a code and learning characteristics of the activation signal for subsequently transmitting a signal having the same characteristics for remotely actuating a device, said trainable transceiver comprising:

  • a dynamically tunable antenna for transmitting a modulated radio frequency carrier signal having a carrier frequency selected from a range of frequencies covering at least the range of 200 to 400 MHz, said dynamically tunable antenna having a control input and a tunable element such that the resonant frequency of said antenna can be varied in response to antenna control data applied to said control input to vary the filtering characteristics of said dynamically tunable antenna to provide a pass band substantially centered about the carrier frequency of said modulated radio frequency carrier signal;

    a controller coupled to said dynamically tunable antenna and operable in a learning and an operating mode, said controller receiving an activation signal in said learning mode for storing data corresponding to the radio frequency and code of the activation signal, and in said operating mode, providing output data, which identifies the radio frequency and code of the received activation signal, wherein said controller further provides antenna control data to said control input of said dynamically tunable antenna in order to selectively control the resonant frequency of said dynamically tunable antenna; and

    a signal generator coupled to said controller and said dynamically tunable antenna, for receiving said output data from said controller and for transmitting a modulated radio frequency carrier signal, which corresponds to the received activation signal, from said dynamically tunable antenna,wherein, during said operating mode, said controller selects and outputs antenna control data corresponding to the radio frequency identified in the output data supplied to said signal generator such that said dynamically tunable antenna filters harmonic frequency components from said modulated radio frequency carrier signal generated by said signal generator.

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