Speakerphone using digitally compressed audio to control voice path gain

A radiotelephone for communicating voice signals by way of a radio channel, comprising:

• microphone means for producing a first signal including voice signals;
• speaker means for emitting a second signal including voice signals;
• radio means for transmitting the first signal on and receiving the second signal from the radio channel;
• 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.

A radiotelephone for communicating voice signals by way of a radio channel, comprising:

• microphone means for producing a first signal including voice signals;
• speaker means for emitting a second signal including voice signals;
• radio means for transmitting the first signal on and receiving the second signal from the radio channel;
• 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;
• ananog-to-digital converter means alternately coupled to the output of said compressor amplifying means and the input of said expander amplifying means;
• and
• control means coupled to said ananog-to-digital converter 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.