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公开(公告)号：DE69114129T2
公开(公告)日：1996-06-13
申请号：DE69114129
申请日：1991-07-17
Applicant: IBM
Inventor： ABBIATE JEAN-CLAUDE , BLANC ALAIN , JEANNIOT PATRICK , ORENGO GERARD , RICHTER GERARD
Abstract: A decimation filter for converting a train of sigma-delta pulses S(i) in synchronism with a sigma-delta clock into a train of PCM samples which includes counting means (321, 331, 341) driven by the sigma-delta clock (fs) and which is continuously incremented by one during N sigma-delta clock pulses, then decremented by two during N following sigma-delta clock pulses and then incremented again by one during N following sigma-delta clock pulses in order to provide a sequence of incrementation parameter DELTA(n). The decimation filter further includes storing means (320, 330, 340) for storing the value of the coefficient C(n) corresponding to the decimation filter transfer function, and means (327, 337, 347) driven by the sigma-delta clock for incrementing the storing means with the incrementation parameter DELTA(n). At last, the decimation filter includes computing means (323, 333, 343, 327, 337, 347) for deriving from the contents C(n) of said storing means and from the train of input sigma-delta samples S(i+n) one Pulse Code Modulation (PCM) sample every 3xN input sigma-delta samples according to the formula: Since the coefficients C(n) are directly and on-line computed with the reception of the sigma-delta pulses, the decimation filter can operate for any value of the decimation parameter without requiring the use of substantial digital processing resources. The decimation filter can be used for a wide variety of different applications requiring different decimation factors.
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公开(公告)号：DE69114129D1
公开(公告)日：1995-11-30
申请号：DE69114129
申请日：1991-07-17
Applicant: IBM
Inventor： ABBIATE JEAN-CLAUDE , BLANC ALAIN , JEANNIOT PATRICK , ORENGO GERARD , RICHTER GERARD
Abstract: A decimation filter for converting a train of sigma-delta pulses S(i) in synchronism with a sigma-delta clock into a train of PCM samples which includes counting means (321, 331, 341) driven by the sigma-delta clock (fs) and which is continuously incremented by one during N sigma-delta clock pulses, then decremented by two during N following sigma-delta clock pulses and then incremented again by one during N following sigma-delta clock pulses in order to provide a sequence of incrementation parameter DELTA(n). The decimation filter further includes storing means (320, 330, 340) for storing the value of the coefficient C(n) corresponding to the decimation filter transfer function, and means (327, 337, 347) driven by the sigma-delta clock for incrementing the storing means with the incrementation parameter DELTA(n). At last, the decimation filter includes computing means (323, 333, 343, 327, 337, 347) for deriving from the contents C(n) of said storing means and from the train of input sigma-delta samples S(i+n) one Pulse Code Modulation (PCM) sample every 3xN input sigma-delta samples according to the formula: Since the coefficients C(n) are directly and on-line computed with the reception of the sigma-delta pulses, the decimation filter can operate for any value of the decimation parameter without requiring the use of substantial digital processing resources. The decimation filter can be used for a wide variety of different applications requiring different decimation factors.
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公开(公告)号：DE68913967T2
公开(公告)日：1994-09-22
申请号：DE68913967
申请日：1989-07-12
Applicant: IBM
Inventor： FERRY MICHEL , PANTANI JEAN-PIERRE , ORENGO GERARD , RICHTER GERARD
IPC: H03M3/02
Abstract: A sigma-delta converter including a switching component (313) controlled by a first clock (308) having determined transitions for generating a train of sigma-delta code pulses corresponding to an analog input value. The sigma-delta includes means (306, 310, 311) for generating a second clock (350) of a same frequency than the first clock and having a negative transition followed after a defined period of time (d2) by a positive transition. The determined transitions of the first clock controlling the swithing element occur during said defined period of time. There is also included means (305) controlled by the sigma-delta code pulse train and said second clock for generating a train of sigma-delta pulses being insensitive to the mismatch of the rise and fall times of said switching element (313) whereby improving the linearity and the signal-to-noise ration of the converter. The control of the said period of time allows the varying of the energy of the pulses in order to provide pulses train which, when applied to a sigma-delta decoder, provides an analog output value representative but attenuated with respect to the analog input value.
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Patent Agency Ranking
公开(公告)号：DE69223508D1
公开(公告)日：1998-01-22
申请号：DE69223508
申请日：1992-07-10
Applicant: IBM
Inventor： ABBIATE JEAN-CLAUDE , BLANC ALAIN , JEANNIOT PATRICK , RICHTER GERARD
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公开(公告)号：CA2112767C
公开(公告)日：1997-03-18
申请号：CA2112767
申请日：1994-01-04
Applicant: IBM
Inventor： CESARO CLAUDE , RICHTER GERARD
Abstract: Tone-detection method for a call-progress process which detects at least one tone in a multifrequency dual-tone signal in a telecommunication apparatus having digital signal processing resources. The method involves the step of: - computing (201) the value of the energy of the signal, - processing (201) said received signal to determine the existence of one or twotones in said signal, - applying a second-order or fourth-order autoregressive process in response to said determination and performing (203, 208) a first estimation of the autoregressive parameters of said received signal, - performing a digital band-pass filtering operation (205,210) adjusted to the result of the estimation of said autoregressive parameters to provide a partial elimination of the noise existing on said received signal, - reapplying (205, 210) a second-order or fourth-order autoregressive process in response to said determination and performing a final estimation of the autoregressive parameters of said received signal, - computing (206, 211) the values of the frequencies each tone from the value of said estimated parameters. The determination of the number of tones existing in the signal is achieved by the computation of the ratio: which is theorically equal to 2 in the case of a unique tone, and conversely should be 4 in that of a dual tone. The first and final second-order autoregressive process are based on the predicting function having the ztransfer function: and which is associated with a Least Mean Square algorithm continuously adapting the parameters of the predictor in a sense allowing the minimizing of an error signal. On the other hand, the first and final fourth-order autoregressive process are based on the predicting function having the ztransfer function: To increase the accuracy of the tone-detection mechanism, the second-order autoregressive function is performed with the value of a2 parameter being constantly fixed to -1. Similarly, the fourth-order autoregressive process is performed with the values of a3 and a4 being respectively equal to a? and -1. The digital filter which provides the suppression of most of the noise existing in the signal having an unique tone is based on the z-transfer function: In the case of a dual-tone, the filtering is based on the function: Fig. 2
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公开(公告)号：DE69118372T2
公开(公告)日：1996-11-14
申请号：DE69118372
申请日：1991-07-17
Applicant: IBM
Inventor： ABBIATE JEAN-CLAUDE , BLANC ALAIN , JEANNIOT PATRICK , RICHTER GERARD
Abstract: A Decimation filter for converting a train of sigma-delta pulses in synchronism with a sigma-delta clock (fs) into a train of Pulse Code Modulation (PCM) samples in accordance with the formula The decimation filter comprises means for computing one PCM sample from a sequence of 1 sigma-delta samples in synchronism with a PCM clock. and also means for determining whether a phase correction has to be introduced in said PCM clock in order to lock the generation of the PCM samples on the receive clock extracted from the received signal. From the latter determination, the decimation filter has means (410, 311, 411, 312, 412, 313) which shifts the computation process of the sequence of at least one sigma-delta clock pulse in order to provide a phase control of the generation of the PCM samples. In a preferred embodiment, the value of p is equal to 3 and the filter includes computing means (350, 360, 370) for computing one PCM sample from a sequence of 3xN input samples according to the formula: where C(n) is the sequence of the coefficients of the decimation filter corresponding to a determined decimation factor N. The filter further includes - means (321, 327, 331, 337, 341, 347) for generating the sequence C(n) corresponding to a determined decimation factor N, and multiplying means (323, 333, 343) for multiplying each coefficient C(n) of said sequence by a sigma-delta input sample S(i+n). The filter detects the occurence of the coefficient C(2xN-1) which is equal to zero and includes means (311, 312, 313) responsive to the detection of said coefficient C(2xN-1) for shifting of one sigma-delta clock pulse the initiating of the computing process of the next PCM pulse in order to provide a phase control of the generation of the PCM samples.
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公开(公告)号：DE69118372D1
公开(公告)日：1996-05-02
申请号：DE69118372
申请日：1991-07-17
Applicant: IBM
Inventor： ABBIATE JEAN-CLAUDE , BLANC ALAIN , JEANNIOT PATRICK , RICHTER GERARD
Abstract: A Decimation filter for converting a train of sigma-delta pulses in synchronism with a sigma-delta clock (fs) into a train of Pulse Code Modulation (PCM) samples in accordance with the formula The decimation filter comprises means for computing one PCM sample from a sequence of 1 sigma-delta samples in synchronism with a PCM clock. and also means for determining whether a phase correction has to be introduced in said PCM clock in order to lock the generation of the PCM samples on the receive clock extracted from the received signal. From the latter determination, the decimation filter has means (410, 311, 411, 312, 412, 313) which shifts the computation process of the sequence of at least one sigma-delta clock pulse in order to provide a phase control of the generation of the PCM samples. In a preferred embodiment, the value of p is equal to 3 and the filter includes computing means (350, 360, 370) for computing one PCM sample from a sequence of 3xN input samples according to the formula: where C(n) is the sequence of the coefficients of the decimation filter corresponding to a determined decimation factor N. The filter further includes - means (321, 327, 331, 337, 341, 347) for generating the sequence C(n) corresponding to a determined decimation factor N, and multiplying means (323, 333, 343) for multiplying each coefficient C(n) of said sequence by a sigma-delta input sample S(i+n). The filter detects the occurence of the coefficient C(2xN-1) which is equal to zero and includes means (311, 312, 313) responsive to the detection of said coefficient C(2xN-1) for shifting of one sigma-delta clock pulse the initiating of the computing process of the next PCM pulse in order to provide a phase control of the generation of the PCM samples.
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公开(公告)号：CA2112767A1
公开(公告)日：1994-10-30
申请号：CA2112767
申请日：1994-01-04
Applicant: IBM
Inventor： CESARO CLAUDE , RICHTER GERARD
Abstract: Tone-detection method for a call-progress process which detects at least one tone in a multifrequency dual-tone signal in a telecommunication apparatus having digital signal processing resources. The method involves the step of: computing (201) the value of the energy of the signal, processing (201) said received signal to determine the existence of one or two tones in said signal, applying a second-order or fourth-order autoregressive process in response to said determination and performing (203, 208) a first estimation of the autoregressive parameters of said received signal, performing a digital band-pass filtering operation (205,210) adjusted to the result of the estimation of said autoregressive parameters to provide a partial elimination of the noise existing on said received signal, reapplying (205, 210) a second-order or fourth-order autoregressive process in response to said determination and performing a final estimation of the autoregressive parameters of said received signal, computing (206, 211) the values of the frequencies each tone from the value of said estimated parameters. The determination of the number of tones existing in the signal is achieved by the computation of the ratio: which is theorically equal to 2 in the case of a unique tone, and conversely should be 4 in that of a dual tone. The first and final second-order autoregressive process are based on the predicting function having the z-transfer function: and which is associated with a Least Mean Square algorithm continuously adapting the parameters of the predictor in a sense allowing the minimizing of an error signal. On the other hand, the first and final fourth-order autoregressive process are based on the predicting function having the z-transfer function: To increase the accuracy of the tone-detection mechanism, the second-order autoregressive function is performed with the value of a2 parameter being constantly fixed to -1. Similarly, the fourth-order autoregressive process is performed with the values of a3 and a4 being respectively equal to a1 and - 1. The digital filter which provides the suppression of most of the noise existing in the signal having an unique tone is based on the z-transfer function: In the case of a dual-tone, the filtering is based on the function:
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