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Re-broadcast system for a plurality of AM signals

  • US 5,471,642 A
  • Filed: 01/28/1994
  • Issued: 11/28/1995
  • Est. Priority Date: 01/28/1994
  • Status: Expired due to Fees
First Claim
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1. Apparatus for simultaneously receiving a plurality of AM signals of widely differing strengths on carriers having frequencies of f1, . . . fi, . . . fN where N is an integer greater than 1 and for re-broadcasting the AM signals at an equal strength and at the original carrier frequencies, said apparatus comprising in combination:

  • a receiving antenna;

    an input bus connected to said receiving antenna;

    an output radiator;

    an output bus connected to said output radiator;

    a plurality of circuit boards, one for each of said plurality of AM signals, each of said plurality of circuit boards connected to said input bus and to said output bus, the circuit board for carrier frequency fi includinga local oscillator producing an output having a frequency equal to fi ±

    fo, where fo is a chosen intermediate frequency (IF) which is the same for all of the circuit boards;

    a down-converter connected to said input bus and connected to said local oscillator and producing an amplitude modulated carrier of frequency fo as an output;

    an IF amplifier connected to receive the output of said down-converter, having a controllable gain, and producing an output;

    first means connected to said IF amplifier for controlling its gain in inverse relation to the strength of the carrier of frequency fi, whereby the gain is reduced if the carrier of frequency fi is strong, and whereby the gain is increased if the carrier of frequency fi is weak;

    an up-converter connected to said IF amplifier and connected to said local oscillator for mixing the output of said IF amplifier of frequency fo with the output of said local oscillator of frequency fi ±

    fo to produce on an output terminal an output of frequency fi having a signal strength that is substantially uniform for all of said plurality of circuit boards; and

    ,second means connecting the output terminal of said up-converter to said output bus.

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