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Privacy communication method and system

  • US 4,244,053 A
  • Filed: 09/10/1970
  • Issued: 01/06/1981
  • Est. Priority Date: 09/10/1970
  • Status: Expired due to Term
First Claim
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1. A privacy communication system comprising means of generating a signal continuously changing frequency with time in accordance with a preset relationship, said generating means being composed of a first frequency synthesizing means, a first digital computer connected to said frequency synthesizing means, said digital computer having the ability to very rapidly read memory storage to determine the increment of frequency change at any instant of time and also being preprogrammed in accordance with the preset relationship in frequency and in time, a first frequency standard serving as a frequency base for said frequency synthesizer means, said frequency standard maintaining frequency stability over an extended period of time, means to selectively impress intelligence upon said generated signal, means to transmit said signal impressed with said intelligence, means to receive the transmitted signal, said receiving means being physically displaced from said transmitting means, a mixer being fed the received signal as a first input signal, a second frequency synthesizing means identical to said first frequency synthesizing means, a second digital computer connected to said second frequency synthesizing means and identical in capability and preprogramming to said first digital computer, a second frequency standard also connected to said second frequency synthesizer means and identical to said first frequency standard, said first and second frequency standard initially being synchronized, said second frequency synthesizer providing a second input signal for said mixer, a receiver being fed the output signal from said mixer, said receiver being utilized as an intermediate frequency amplifier and detector, a post detection device receiving the output signal from said receiver for conversion to the initially impressed intelligence, and a threshold detector also receiving the output signal of said receiver and providing a control signal to said second digital computer.

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