Loudspeaking telephone system
First Claim
1. In a loudspeaking telephone system of the type in which voice signals on transmission and reception speech channels are respectively detected to produce control signals, and these control signals are compared to judge the levels of the voice signals on both the speech channels so that the switching between both the channels is effected under the control of loss of digitally controlled attenuators inserted in both the speech channels, the improvement wherein said system comprises:
- means for converting the control signals corresponding to the voice signals on both the transmission and reception speech channels through analog-to-digital conversion into digital signals; and
means, with the use of a microprocessor as a calculating unit, for comparing the magnitudes of transmission and reception signals by arithmetic operation on the digital signals attained through said conversion, and effecting a control of the switching of the loss of said digitally controlled attenuators based on the result of said comparison.
2 Assignments
0 Petitions
Accused Products
Abstract
A loudspeaking telephone system has a voice switch circuit in which voice signals on transmission and reception speech channels are respectively detected to produce control signals, and these control signals are compared to judge the levels of the voice signals on both the speech channels so that the switching between both the channels is effected under the control of loss of variable attenuators inserted in both the speech channels. The control signals corresponding to the voice signals on both the transmission and reception speech channels are converted through analog-to-digital conversion into digital values which are suitable for arithmetic operation. The arithmetic operation is such that the losses of the variable attenuators are automatically controlled in accordance with the use conditions of the loudspeaking telephone system to minimum values which can prevent the howling, transmitting blocking and receiving blocking.
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Citations
5 Claims
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1. In a loudspeaking telephone system of the type in which voice signals on transmission and reception speech channels are respectively detected to produce control signals, and these control signals are compared to judge the levels of the voice signals on both the speech channels so that the switching between both the channels is effected under the control of loss of digitally controlled attenuators inserted in both the speech channels, the improvement wherein said system comprises:
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means for converting the control signals corresponding to the voice signals on both the transmission and reception speech channels through analog-to-digital conversion into digital signals; and means, with the use of a microprocessor as a calculating unit, for comparing the magnitudes of transmission and reception signals by arithmetic operation on the digital signals attained through said conversion, and effecting a control of the switching of the loss of said digitally controlled attenuators based on the result of said comparison. - View Dependent Claims (2, 3, 4, 5)
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Specification