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System for separately receiving multiple station audio-tour signals

  • US 4,457,019 A
  • Filed: 08/12/1982
  • Issued: 06/26/1984
  • Est. Priority Date: 08/12/1982
  • Status: Expired due to Fees
First Claim
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1. An audio-tour system in which a visitor may receive a different message at each of a plurality of pre-determined listening zones including:

  • means for producing a first carrier wave,means for producing a second carrier wave, the frequency of said second carrier wave being different from that of said first carrier wave,means for amplitude modulating each said wave with respective different messages,a first induction loop and a second induction loop spaced from one another and connected to said last-named means, to transmit said modulated first and said second carrier waves respectively,an untuned broadband radio receiver having a band-width including the frequencies of said carrier waves and having a substantially flat response curve over the frequencies of said carrier waves, to receive said waves and detect the amplitude modulation thereon, andthe signal strength of the signals transmitted from said first induction loop approximating the signal strength of the signals transmitted from said second induction loop,whereby, when the system is used, one said carrier wave will dominate the other said carrier wave, depending upon the relative signal strengths of said waves at said receiver, and thereby effect a substantial reduction in cross-talk between said two transmitted messages.

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