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Card-type electronic device for adding a data communication function to an apparatus without hardware modification of the apparatus

  • US 6,038,431 A
  • Filed: 03/08/1995
  • Issued: 03/14/2000
  • Est. Priority Date: 03/14/1994
  • Status: Expired due to Fees
First Claim
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1. A card-type electronic device for optional use without hardware modification of an apparatus by insertion into said apparatus, said device comprising:

  • (a) a receiving system for selecting a desired channel from a digitally modulated signal, including;

    a signal input terminal supplied with a high-frequency signal;

    a mixer having an input port supplied with a signal from the signal input terminal and another input port for receiving an output of a local oscillator;

    an output terminal supplied with an output signal of the mixer;

    a PLL circuit having an input port for receiving the output of the local oscillator and a PLL signal output port for connection to an input of the local oscillator;

    a DC-DC converter connected to a power input terminal, an output of said DC-DC converter being connected to said PLL circuit so as to reduce a load on said apparatus in obtaining a tuning voltage;

    a data input terminal for supplying a data signal to said PLL circuit; and

    a digital signal processing means including at least one of an extraction means for performing a frequency conversion to extract a signal containing information of an absolute value from a carrier wave in a digitally-modulated output signal from said mixer and for use in digital signal processing of the extracted signal and an A/D converter connected between the mixer and the output terminal;

    wherein said mixer and said local oscillator are arranged in a vicinity of said signal input terminal so as to minimize input level attenuation;

    (b) a transmitting system for digitally modulated signal including;

    a transmission signal input terminal;

    digital modulation processing means connected to said transmission signal input terminal; and

    a transmission signal output terminal coupled to said digital modulation processing means; and

    (c) a card-type case having a protrusion to meet an increased circuit requirement, said receiving system and said transmitting system being packed in said card-type case;

    wherein said output terminal, said data input terminal, said power input terminal and said transmission signal input terminal are arranged on a lateral side of said case, and wherein said signal input terminal and said transmission signal output terminal are coupled to a duplexer connected to a single signal input/output terminal so as to prevent an output signal from said digital modulation processing means from circumventing into the receiving system.

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