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DIGITAL COMMUNICATION SYSTEM

  • US 3,678,391 A
  • Filed: 04/06/1970
  • Issued: 07/18/1972
  • Est. Priority Date: 04/06/1970
  • Status: Expired due to Term
First Claim
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1. In a two-way communication system, a radio unit capable of transmitting and receiving both voice and digital electrical signals comprising a transceiver for transmitting and receiving electrical signals, antenna means coupling electrical signals to and from said transceiver, clock means for generating clock pulses having high and low pulse repetition frequencies, control means for selectively producing a digital signal characterized by binary amplitude levels comprising means for generating a digital synchronization word and a unique digital word identifying a particular radio unit, means for generating a digital message word, logic means for combining the digital words from said first and second generating means for assembling the selected digital signal, and message means selectively manually actuated to generate a control pulse for initiating transmission of the assembled digital signal, said logic means being responsive to said control pulse for selectively passing said low frequency clock pulses, means responsive to the output of said logic means for converting said selected digital signal to an aNalog signal comprising a first digital compiler responsive to the operation of said logic means for simultaneously receiving into prescribed stages thereof said digital identification, synchronization and message words and responsive to said clock pulses passed by said logic means for sequentially advancing the contents of said first compiler for producing a serial digital output signal, and an encoder responsive to the first serial digital signal for generating an electrical signal having one frequency when the amplitude of said serial signal has one binary value and generating another electrical signal having another frequency when the amplitude of said serial digital signal is a second binary value, said transceiver being responsive to said analog signals from said converting means for transmitting same through said antenna means and responsive to such signals from said antenna means for producing received analog signals, means connected to the output of said transceiver for automatically reconverting received analog signals to corresponding binary amplitude level received digital signals, and indicating means responsive to the outputs of said logic means and said reconverting means for providing readable indications of selected and received digital signals, respectively.

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