EP0376589A2
Expired / Lapsed
EP
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Self calibration arrangement for a voice switched speakerphone
Assignee: AT&T Inc
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Filing: 1989-12-19
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Granted: —
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Expires: 2009-12-19
Abstract
Abstract An electrical calibration (110,113) in a voice switched adaptive speakerphone accurately determines the operating parameters of the speakerphone for optimal performance before operation. This is achieved by updating thresholds used to determine when the speakerphone should be in each of three possible operating states; transmit, receive or idle. During operation, these thresholds are compared with transmit and receive signal strength levels to determine the state of the speakerphone. The thresholds are updated to counteract the effects of variation and aging of hardward circuits in the speakerphone and are obtained by having the calibration circuit generate a test tone signal which is passed through speech processing circuitry (200,300) in the speakerphone at two different levels and the resulting response measured. Since the calibration circuit has available the initial levels of the test tone signal that is passed through the speech processing circuitry and measures the relative levels of the signal that returns, the calibration circuit can adjust the speakerphone thresholds before operating to account for any variation in the circuitry. This test tone signal is passed through both a transmit speech path (200) and a receive speech path (300) in the speakerphone circuitry to separately adjust for variations in each speech path. In this manner, essentially equal thresholds are commonly set up for each path, even though the values of corresponding circuit components in the paths may differ considerably.
Inventors
- 👤 Richard Henry Erving
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-01 12:53
CPC Classifications
H; H04; H04M; H04M1/00; H04M1/60; H04M9/00; H04M9/08; H04M9/085
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
141 words
A voice switching apparatus for processing speech signals on a communication line including means for switching between a receive state for receiving speech signals from the communication line and a transmit state for transmitting speech signals over the communication line, CHARACTERIZED IN; including an electrical calibration circuit for determining the operational readiness of speech processing circuitry in the apparatus and comprising: means (110, 113) for generating a tone signal; means for coupling this tone signal in a loop configuration through the speech processing circuitry; means (110) for detecting the return of the tone signal; means (110) responsive to the return of the tone signal for measuring the form of said returned tone signal; and calibration (110) means operably responsive to the measuring means for adjusting threshold switching levels at which the apparatus switches between the receive state and the transmit state.
Claim 2
Dependent Claim
141 words
A voice switching apparatus for processing speech signals on a communication line including means for switching between a receive state for receiving speech signals from the communication line and a transmit state for transmitting speech signals over the communication line, CHARACTERIZED IN; including an electrical calibration circuit for determining the operational readiness of speech processing circuitry in the apparatus and comprising: means (110, 113) for generating a tone signal; means for coupling this tone signal in a loop configuration through the speech processing circuitry; means (110) for detecting the return of the tone signal; means (110) responsive to the return of the tone signal for measuring the form of said returned tone signal; and calibration (110) means operably responsive to the measuring means for adjusting threshold switching levels at which the apparatus switches between the receive state and the transmit state.
Claim 3
Dependent Claim
43 words
The electrical calibration circuit as in claim 1 further CHARACTERIZED IN THAT. the tone signal is generated by the tone generating means at a first amplitude and at a second reduced amplitude for coupling in the loop configuration through the speech processing circuitry.
Claim 4
Dependent Claim
65 words
The electrical calibration circuit as in claim 2 further CHARACTERIZED IN THAT the measuring means includes comparison means for comparing the amplitude levels of the returned tone signal, the difference between the two levels providing a basic constant of proportionality reflective of the speech coupling efficiency of the speech processing circuitry, and the comparison means providing the basic constant of proportionality to the calibration means.
Claim 5
Dependent Claim
70 words
The electrical calibration circuit as in claim 3 further CHARACTERIZED IN THAT the speech processing circuitry comprises a transmit section for processing the speech signals for transmission over the communication line and a receive section for processing the speech signals received from the communication line, the tone signal being separately coupled through both the transmit section and the receive section for determing the basic constant of proportionality for each section.
Claim 6
Independent Claim
122 words
A method of determining the operational readiness of speech processing circuitry in a voice signal controller connectable to a communication line, the voice signal controller switching between a receive state for receiving speech signals from the communication line and a transmit state for transmitting speech signals over the communication line, CHARACTERIZED IN THAT the method comprises the steps of: generating a tone signal; coupling this tone signal in a loop configuration through the speech processing circuitry; detecting the return of the tone signal; measuring the form of said returned tone signal; and adjusting threshold switching levels at which the controller switches between the receive state for receiving speech signals and the transmit state for transmitting speech signals responsive to the measuring step.
Claim 7
Independent Claim
122 words
A method of determining the operational readiness of speech processing circuitry in a voice signal controller connectable to a communication line, the voice signal controller switching between a receive state for receiving speech signals from the communication line and a transmit state for transmitting speech signals over the communication line, CHARACTERIZED IN THAT the method comprises the steps of: generating a tone signal; coupling this tone signal in a loop configuration through the speech processing circuitry; detecting the return of the tone signal; measuring the form of said returned tone signal; and adjusting threshold switching levels at which the controller switches between the receive state for receiving speech signals and the transmit state for transmitting speech signals responsive to the measuring step.
Claim 8
Dependent Claim
49 words
A method of determining the operational readiness of speech processing circuitry as in claim 5 further CHARACTERIZED IN THAT the tone generating step includes generating the tone signal at a first amplitude and at a second reduced amplitude for coupling in the loop configuration through the speech processing circuitry.
Claim 9
Dependent Claim
84 words
A method of determining the operational readiness of speech processing circuitry as in claim 6 further CHARACTERIZED IN THAT the measuring step further includes the step of comparing the amplitude levels of the returned tone signal, the difference between the two levels providing a basic constant of proportionality reflective of the speech coupling efficiency of the speech processing circuitry, and the threshold switching levels adjusting step responsive to the comparison step adjusting the threshold switching levels in accordance with the basic constant of proportionality.
Claim 10
Dependent Claim
81 words
A method of determining the operational readiness of speech processing circuitry as in claim 7 further CHARACTERIZED IN THAT the speech processing circuitry comprises a transmit section for processing the speech signals for transmission over the communication line and a receive section for processing the speech signals received from the communication line, the tone signal being separately coupled by the coupling step through both the transmit section and the receive section for determining the basic constant of proportionality for each section.
References Cited (Backward Citations)
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