公开(公告)号：WO1997020438A1

公开(公告)日：1997-06-05

申请号：PCT/US1996016492

申请日：1996-10-15

Applicant: ADVANCED MICRO DEVICES, INC.

Inventor： ADVANCED MICRO DEVICES, INC. ,  XIE, Zheng-yi ,  BARTKOWIAK, John, G.

IPC: H04Q01/457

CPC classification number: H04Q1/453 ,  H04M7/1295 ,  H04Q1/457

Abstract: An improved dual tone multifrequency (DTMF) signal detector which uses the Goertzel DFT algorithm and which utilizes variable or differing frame widths that are frequency dependent for improved detection and reduced error. The DTMF detector includes a codec receiver which receives signals from the transmission media, and a digital signal processor (DSP) coupled to the codec. The DSP receives the digital samples and preferably applies the Goertzel DFT algorithm using differing frame lengths according to the present invention. The DTMF detector utilizes a different frame width for different tones of the possible tone frequencies according to the present invention. Thus the calculation uses a different frame length N for different ones of the uncorrelated frequencies, wherein the different frame lengths comprise at least a subset N of the number of digital samples. The different frame lengths N are designed to optimally align the calculated frequency spectrum at each of the different uncorrelated frequencies. The calculation produces an energy value for each of the different uncorrelated frequencies. The DTMF detector preferably multiplies a gain value with each of the energy values to adjust the gain of each of the energy values. After the frequency domain calculation, i.e., after energy values have been calculated for each of the different uncorrelated frequencies, and after any desired gain adjustment, the DSP determines maximum values of the energy values for each of the two or more frequency groups to detect the plurality of tones in the received signal. The DTMF detector also performs various other calculations to ensure valid tone detection.

Abstract translation: 改进的双音多频（DTMF）信号检测器，其使用Goertzel DFT算法，并且利用与频率相关的可变或不同的帧宽度来改善检测和减少误差。 DTMF检测器包括从传输介质接收信号的编解码器接收器和耦合到编解码器的数字信号处理器（DSP）。 DSP接收数字样本，并且优选地根据本发明应用使用不同帧长度的Goertzel DFT算法。 根据本发明，DTMF检测器对于可能的音调频率的不同音调使用不同的帧宽度。 因此，不同的不相关频率的计算使用不同的帧长度N，其中不同的帧长度至少包括数字样本数量的子集N。 不同的帧长度N被设计成在每个不相关的频率下优化对准所计算的频谱。 该计算产生每个不相关频率的能量值。 DTMF检测器优选地将增益值与每个能量值相乘以调整每个能量值的增益。 在频域计算之后，即，在针对每个不相关的频率计算能量值之后，并且在任何期望的增益调整之后，DSP确定两个或更多个频率组中的每一个的能量值的最大值，以检测 接收信号中的多个音调。 DTMF检测器还执行各种其他计算，以确保有效的音调检测。

公开(公告)号：WO1997046030A1

公开(公告)日：1997-12-04

申请号：PCT/US1997002511

申请日：1997-02-18

Applicant: ADVANCED MICRO DEVICES, INC.

Inventor： ADVANCED MICRO DEVICES, INC. ,  BARTKOWIAK, John, G. ,  XIE, Zheng-yi

IPC: H04Q01/457

CPC classification number: H04Q1/457 ,  H04L27/30 ,  H04Q1/453

Abstract: An improved dual tone multifrequency (DTMF) or multitone multifrequency (MTMF) signal detector which more efficiently detects DTMF signals. For each received frame, the present invention initially performs only a portion of the Goertzel DFT algorithm for each of the possible tone frequencies and then analyzes the interim accumulated energies. The DTMF detector then selects one or more frequencies from each of the tone groups which have the largest energy values, and the detector only completes calculation of the Goertzel DFT algorithm on those selected one or more frequencies. In other words, the DTMF detector discontinues calculation of the Goertzel DFT algorithm on one or more frequencies which have low accumulated interim energies. This reduces the computational requirements and provides improved performance.

Abstract translation: 改进的双音多频（DTMF）或多音多频（MTMF）信号检测器，可更有效地检测DTMF信号。 对于每个接收的帧，本发明最初仅针对每个可能的音调频率执行Goertzel DFT算法的一部分，然后分析临时累积的能量。 然后，DTMF检测器从具有最大能量值的每个音调组中选择一个或多个频率，并且检测器仅完成所选择的一个或多个频率上的Goertzel DFT算法的计算。 换句话说，DTMF检测器在具有低累积临时能量的一个或多个频率上中断对Goertzel DFT算法的计算。 这减少了计算需求并提供了改进的性能。

公开(公告)号：WO1997025822A1

公开(公告)日：1997-07-17

申请号：PCT/US1997000505

申请日：1997-01-10

Applicant: ADVANCED MICRO DEVICES, INC.

Inventor： ADVANCED MICRO DEVICES, INC. ,  XIE, Zheng-yi

IPC: H04Q01/457

CPC classification number: H04Q1/453 ,  H04Q1/457

Abstract: An improved dual tone multifrequency (DTMF) or multitone signal detector which uses both static and dynamic thresholding techniques to provide an increased functional dynamic range, improved speech immunity for improved detection and reduced error, and simplified signal to noise ratio control. The DTMF detector receives signals from the transmission media, calculates energy values for the different frequencies, and then determines maximum values of the energy values for each of the frequency groups, referred to as M(1) and M(2). The DTMF detector then performs both static and dynamic thresholding according to the present invention to ensure valid tone detection. The static thresholding compares each of the M(1) and M(2) values with a static threshold value to ensure that the maximum energy values have a minimum energy to warrant detection. Since both static and dynamic thresholding are performed according to the present invention, the static threshold value is preferably set low, thus allowing an increased functional dynamic range. The dynamic thresholding computes the ratio of the maximum value in each sub-array to each of the other values in the respective sub-array, wherein the remaining values in the sub-array are presumed to be noise. This ratio essentially computes the signal to noise ratio (SNR) of the received signals. These ratios are then compared with a second threshold. If the maximum energies are not greater than the static threshold, or any of the ratios is not greater than the second threshold value, then a SNR error is set, and no detection is indicated. The present invention improves the DTMF detector's functional dynamic range and noise immunity.

Abstract translation: 改进的双音多频（DTMF）或多音频信号检测器，其使用静态和动态阈值技术来提供增加的功能动态范围，改进的语音抗扰度，用于改进的检测和减少的误差，以及简化的信噪比控制。 DTMF检测器从传输介质接收信号，计算不同频率的能量值，然后确定每个频率组的能量值的最大值，称为M（1）和M（2）。 然后，DTMF检测器根据本发明执行静态和动态阈值，以确保有效的音调检测。 静态阈值将M（1）和M（2）值中的每一个与静态阈值进行比较，以确保最大能量值具有最小能量以保证检测。 由于根据本发明执行静态和动态阈值处理，静态阈值优选地被设置为低，从而允许增加的功能动态范围。 动态阈值计算每个子阵列中的最大值与相应子阵列中的每个其它值的比率，其中子阵列中的剩余值被推定为噪声。 该比率基本上计算接收信号的信噪比（SNR）。 然后将这些比率与第二阈值进行比较。 如果最大能量不大于静态阈值，或任何比率不大于第二阈值，则设置SNR误差，并且不指示检测。 本发明改进了DTMF检测器的功能动态范围和抗噪声能力。

公开(公告)号：EP0872122A1

公开(公告)日：1998-10-21

申请号：EP97901443.0

申请日：1997-01-10

Applicant: Advanced Micro Devices, Inc.

Inventor： XIE, Zheng-yi

IPC: H04Q1

CPC classification number: H04Q1/453 ,  H04Q1/457

Abstract: An improved dual tone multifrequency (DTMF) or multitone signal detector which uses both static and dynamic thresholding techniques to provide an increased functional dynamic range, improved speech immunity for improved detection and reduced error, and simplified signal to noise ratio control. The DTMF detector receives signals from the transmission media, calculates energy values for the different frequencies, and then determines maximum values of the energy values for each of the frequency groups, referred to as M(1) and M(2). The DTMF detector then performs both static and dynamic thresholding according to the present invention to ensure valid tone detection. The static thresholding compares each of the M(1) and M(2) values with a static threshold value to ensure that the maximum energy values have a minimum energy to warrant detection. Since both static and dynamic thresholding are performed according to the present invention, the static threshold value is preferably set low, thus allowing an increased functional dynamic range. The dynamic thresholding computes the ratio of the maximum value in each sub-array to each of the other values in the respective sub-array, wherein the remaining values in the sub-array are presumed to be noise. This ratio essentially computes the signal to noise ratio (SNR) of the received signals. These ratios are then compared with a second threshold. If the maximum energies are not greater than the static threshold, or any of the ratios is not greater than the second threshold value, then a SNR error is set, and no detection is indicated. The present invention improves the DTMF detector's functional dynamic range and noise immunity.

公开(公告)号：EP0872122B1

公开(公告)日：2003-08-27

申请号：EP97901443.8

申请日：1997-01-10

Applicant: Advanced Micro Devices, Inc.

Inventor： XIE, Zheng-yi

IPC: H04Q1/457 ,  H04Q1/453

CPC classification number: H04Q1/453 ,  H04Q1/457

公开(公告)号：EP0864233B1

公开(公告)日：2002-02-06

申请号：EP96936506.3

申请日：1996-10-15

Applicant: Advanced Micro Devices, Inc.

Inventor： XIE, Zheng-yi ,  BARTKOWIAK, John, G.

IPC: H04Q1/457 ,  H04Q1/453

CPC classification number: H04Q1/453 ,  H04M7/1295 ,  H04Q1/457

公开(公告)号：EP0864233A1

公开(公告)日：1998-09-16

申请号：EP96936506.0

申请日：1996-10-15

Applicant: Advanced Micro Devices, Inc.

Inventor： XIE, Zheng-yi ,  BARTKOWIAK, John, G.

IPC: H04Q1

CPC classification number: H04Q1/453 ,  H04M7/1295 ,  H04Q1/457

Abstract: An improved dual tone multifrequency (DTMF) signal detector which uses the Goertzel DFT algorithm and which utilizes variable or differing frame widths that are frequency dependent for improved detection and reduced error. The DTMF detector includes a codec receiver which receives signals from the transmission media, and a digital signal processor (DSP) coupled to the codec. The DSP receives the digital samples and preferably applies the Goertzel DFT algorithm using differing frame lengths according to the present invention. The DTMF detector utilizes a different frame width for different tones of the possible tone frequencies according to the present invention. Thus the calculation uses a different frame length N for different ones of the uncorrelated frequencies, wherein the different frame lengths comprise at least a subset N of the number of digital samples. The different frame lengths N are designed to optimally align the calculated frequency spectrum at each of the different uncorrelated frequencies. The calculation produces an energy value for each of the different uncorrelated frequencies. The DTMF detector preferably multiplies a gain value with each of the energy values to adjust the gain of each of the energy values. After the frequency domain calculation, i.e., after energy values have been calculated for each of the different uncorrelated frequencies, and after any desired gain adjustment, the DSP determines maximum values of the energy values for each of the two or more frequency groups to detect the plurality of tones in the received signal. The DTMF detector also performs various other calculations to ensure valid tone detection.