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Speakerphone using digitally compressed audio to control voice path gain

  • US 4,741,018 A
  • Filed: 04/24/1987
  • Issued: 04/26/1988
  • Est. Priority Date: 04/24/1987
  • Status: Expired due to Term
First Claim
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1. A speakerphone for a radiotelephone for communicating voice signals by way of a radio channel, said radiotelephone including radio means for transmitting a first signal including voice signals on and receiving a second signal including voice signals from the radio channel, said speakerphone comprising:

  • microphone means for producing the first signal;

    speaker means for emitting the second signal;

    compressor amplifying means having an input coupled to said microphone means and an output coupled to said radio means and being responsive to first control signals for selecting one of a plurality of gain settings and amplifying and compressing the first signal;

    expander amplifying means having an input coupled to said radio means and an output coupled to said speaker means and being responsive to second control signals for selecting one of a plurality of gain settings and amplifying and expanding the second signal; and

    control means coupled to the output of said compressor amplifying means and the input of said expander amplifying means for detecting voice signals in the first and second signals and, in response to detection of voice signals in one of the first and second signals, producing the first and second control signals for adjusting the gain settings of said compressor amplifying means and said expander amplifying means such that the gain setting for said one of the first and second signals is increased and the gain setting of the other of the first and second signals is decreased.

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