Speakerphone using digitally compressed audio to control voice path gain
First Claim
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.
1 Assignment
0 Petitions
Accused Products
Abstract
A mobile radiotelephone (120) includes a microcomputer (220), speakerphone control circuitry (106) and mobile radio (112). Mobile radio (112) includes a transmitter (242), receiver (244) and a duplexer (243) for coupling the transmitter (242) and receiver (243) to the mobile antenna. In the transmit voice path, speakerphone control circuitry (106) includes switch (201), variable gain amplifier (202), compressor amplifier (203), switch (204), variable gain amplifier (205), and two registers (212-213). In the receive voice path, speakerphone control circuitry (106) includes variable gain amplifier (232), expander amplifier (233), switch (234), variable gain amplifier (235), switch (236) and two registers (216-217). Speakerphone control circuitry (106) also includes rectifier/filter (224), a companding analog-to-digital (A/D) converter (225), two latches (218-219), rectifier/filter (226) and two registers (214-215). Microcomputer (220) accesses registers (212-217) by means of a data bus (222) including address, control and data lines. Microcomputer (220) utilizes digital samples from A/D converter (225) to continuously generate and store in its memory an envelope signal and a valley signal for the transmit and receive voice paths. In order to determine when to switch gain between the voice paths, microcomputer (220) compares the envelope signal to the valley signal to detect the presence of voice signals and, if the voice signals are detected for a pre-selected time, the gain of the path in which voice signals have been detected is increased and the gain of the other path is decreased.
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Citations
20 Claims
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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:
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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. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A radiotelephone for communicating voice signals by way of a radio channel, comprising:
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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. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A radiotelephone for communicating voice signals by way of a radio channel, comprising:
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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. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification