Method and apparatus for digitally controlling gain in a talking path
First Claim
1. An automatic audio level control for use in a bidirectional talking path, comprising:
- a hybrid having a bidirectional port coupled to the talking path, said talking path being associated with a first destination, and a pair of unidirectional analog ports for carrying voice signals;
a first converter connected respectively to the unidirectional analog ports of the hybrid for converting analog signals to a corresponding first set of digital signals, and vice versa;
a processor coupled to a digital port of the first converter for receiving digital signals indicative of the amplitude of corresponding voice signals carried on the talking path, and said processor coupled to a second converter for receiving and processing a second set of digitized voice signals associated with a second destination; and
said processor being programmed to compare the first set of digital signals received from the first converter with respect to the second set of digitized voice signals received from the second converter and dynamically change at least one of said first or second sets of digital signals so that a loop gain in the talking path can effectively be controlled.
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Abstract
A processor controlled test set is disclosed for testing special service circuits of a telecommunication system. A microprocessor controls the overall operation of the test set, while a digital signal processor provides high speed timing signals to the various test circuits for generating the wave forms used in testing, as well as analyzes the test result signals that are converted into digital signals. A calibration of the test generator signals as well as the signal measuring path is carried out prior to the test sequence. The digital signal processor also provides gain control over a talking path to maintain stability thereof. An I/O circuit of the test set provides plural communication paths between remote equipment and the test set to initiate and carry out various tests. Processors in the I/O module are effective to convert the various protocols of the serial data, by way of software, to digital bit streams usable by the test set.
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Citations
42 Claims
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1. An automatic audio level control for use in a bidirectional talking path, comprising:
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a hybrid having a bidirectional port coupled to the talking path, said talking path being associated with a first destination, and a pair of unidirectional analog ports for carrying voice signals; a first converter connected respectively to the unidirectional analog ports of the hybrid for converting analog signals to a corresponding first set of digital signals, and vice versa; a processor coupled to a digital port of the first converter for receiving digital signals indicative of the amplitude of corresponding voice signals carried on the talking path, and said processor coupled to a second converter for receiving and processing a second set of digitized voice signals associated with a second destination; and said processor being programmed to compare the first set of digital signals received from the first converter with respect to the second set of digitized voice signals received from the second converter and dynamically change at least one of said first or second sets of digital signals so that a loop gain in the talking path can effectively be controlled. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A digital control circuit for controlling a gain of analog signals carried on a bidirectional talk path between two sources of audio signals, comprising:
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a first bidirectional communication port associated with a first source of audio signals; a second bidirectional communication port associated with a second source of audio signals; a first codec for receiving audio signals from the first bidirectional communication port and producing corresponding first digital signals, and for receiving digital signals and producing corresponding analog signals coupled to the first bidirectional communication port; a second codec for receiving audio signals from the second bidirectional communication port and producing corresponding second digital signals, and for receiving digital signals and producing corresponding analog signals coupled to the second bidirectional communication port; and a digital processor for receiving the first digital signals from the first codec and producing different digital signals representing first adjusted amplitudes of the corresponding analog signals and coupling the first adjusted amplitude digital signals to the second codec, and for receiving the second digital signals from the second codec and producing different digital signals representing second adjusted amplitudes of the corresponding analog signals and coupling the second adjusted amplitude digital signals to the first codec, whereby directional gain of the analog signals can be controlled. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 35)
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19. A method of controlling gain in a talk path, comprising the steps of:
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receiving plural analog signal samples;
.converting respective amplitudes of the plural analog signal samples to corresponding plural digital signals; integrating the amplitudes represented by the plural digital signals to determine an average composite amplitude; comparing the average composite amplitude with a predetermined target amplitude to determine if an amplitude adjustment is needed; if the average composite amplitude is less than the target amplitude, incrementally increasing the representative amplitudes of digital signals of subsequently received analog signal samples and converting the digital signals with the increased representative amplitudes to corresponding analog samples; if the composite amplitude is greater than the target amplitude, incrementally decreasing the representative amplitudes of the digital signals of subsequently received analog signal samples and converting the digital signals with the decreased representative amplitudes to corresponding analog samples; and transmitting analog signals corresponding to the converted analog samples to a destination receiver. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 36, 37, 38, 39, 40, 41, 42)
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27. A method of carrying out automatic gain control in a digital communication talk path having a channel A carrying digitized voice samples and a channel B carrying other digitized voice samples, comprising the steps of:
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assigning a target voice level to channel A and a different target voice level to channel B; receiving digitized voice samples from a channel A codec and converting the digitized samples to a linear format; receiving digitized voice samples from a channel B codec and converting the digitized samples to the linear format; comparing representative amplitudes of the channel A digitized samples with the channel A target voice level to determine if the representative amplitude thereof should be increased or decreased, and determining a first gain factor to achieve the channel A target voice level; comparing representative amplitudes of the channel B digitized samples with the channel B target voice level to determine if the representative amplitude thereof should be increased or decreased, and determining a second gain factor to achieve the channel B target voice level; multiplying the first gain factor with the second gain factor to determine if the product is greater than unity; and modifying at least one of the first gain factor or the second gain factor so that the product of the resultant gain factors is not greater than unity. - View Dependent Claims (28, 29, 30, 31, 32, 33, 34)
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Specification