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Process for transmission of analog and/or digital information, especially with an in-line arrangement of one, two or more exchanges in telecommunications systems

  • US 4,947,483 A
  • Filed: 01/25/1988
  • Issued: 08/07/1990
  • Est. Priority Date: 01/26/1987
  • Status: Expired due to Fees
First Claim
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1. In a telecommunication system of the kind comprising:

  • a plurality of subscriber stations each capable of generating electrical output signals representative of information, in a given initial frequency range, and each capable of utilizing electrical input signals in the given initial frequency range to reproduce information represented thereby;

    an exchange;

    a plurality of subscriber lines, each connecting one subscriber station to the exchange; and

    a long distance line connected to the exchange;

    the exchange including exchange switching means for connecting each subscriber line to each other subscriber line for local communication and to connect each subscriber line to the long distance line for long distance communication;

    the system improvement comprising;

    the long distance line comprising two branches, an outgoing branch for transmission of the output signals from a subscriber station as outgoing signals to a distant location and an incoming branch for transmission of incoming signals from a distant location;

    said outgoing branch including frequency shifting means for shifting the frequency of an output signal on that branch to produce a frequency shifted outgoing signal;

    said outgoing branch further including filter means, interposed between said exchange and said frequency shifting means, for blocking frequency shifted incoming signals;

    each subscriber station comprising signal separation means for maintaining input signals separate from output signals;

    and each subscriber station comprising demodulator means for demodulating an incoming frequency shifted signal to develop an input signal utilizable for reproduction by the subscriber station.

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