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DTMF signal detection device and method

A signal detection and signal technology, applied in transmission monitoring, electrical components, transmission systems, etc., can solve problems such as error-prone and DTMF signal quality differences, achieve the effect of improving accuracy and stability, and reducing the probability of false alarms

Active Publication Date: 2019-05-28
ASR MICROELECTRONICS CO LTD
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Problems solved by technology

However, in reality, the quality of DTMF signals generated by SLIC chips of different manufacturers is quite different, and the second harmonic energy of DTMF signals generated by some SLIC chips is also relatively large, so the distinction is made according to the energy of the second harmonic error prone

Method used

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  • DTMF signal detection device and method
  • DTMF signal detection device and method
  • DTMF signal detection device and method

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Embodiment Construction

[0030] see figure 2 The DTMF signal detection device 10 provided by the application comprises a sequentially connected total energy threshold judging unit 12, a Goertzel algorithm DFT amplitude calculation unit 14, a DFT amplitude basic criterion unit 16, a sub-frequency band FFT energy calculation unit 18, a sub-frequency band FFT An energy enhancement criterion unit 110 and a DTMF dual-tone frequency retrieval unit 112 .

[0031] The total energy threshold judgment unit 12 is used to split the input speech signal into speech frames one by one, the length of the speech frame can be fixed or variable, preferably the length of the speech frame is fixed to 20ms. The total energy threshold judging unit 12 is also used to calculate the energy of each speech frame in the time domain, and compare it with a certain threshold value, discard the speech frames with energy less than the threshold value, and keep the energy greater than or equal to the threshold value Valued speech fram...

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Abstract

The invention discloses a DTMF signal detection device. The system comprises a total energy threshold judgment unit, a Goertzel algorithm DFT amplitude calculation unit, a DFT amplitude basic criterion unit, a sub-band FFT energy calculation unit, a sub-band FFT energy enhancement criterion unit and a DTMF double-audio-frequency retrieval unit which are connected in sequence. The invention also discloses a DTMF signal detection method. According to the DTMF signal detection method and device, the accuracy and the stability of DTMF signal detection in a complex environment, namely an interference condition, are improved through a dual judgment mode of DFT operation and judgment and FFT operation and judgment, and the false alarm probability is reduced.

Description

technical field [0001] The present application relates to a DTMF signal detection technology, in particular to a DTMF signal detection technology with relatively high accuracy in a complex environment with interference signals. Background technique [0002] Dual-Tone Multi-Frequency (DTMF, Dual-Tone Multi-Frequency) technology is an in-band (in-band) communication signal transmitted between telephone equipment and other communication equipment and switching centers through the audio frequency band on the telephone line, usually used for Transfer phone numbers quickly and reliably. [0003] see figure 1 , which is a dial pad using DTMF technology, which is a 4×4 matrix structure, and the keys in the fourth column can also be omitted. Each row represents a low frequency signal, eg 697Hz, 770Hz, 852Hz and 941Hz respectively. Each column represents a high frequency signal, eg 1209Hz, 1336Hz, 1477Hz and 1633Hz respectively. Each time a key is pressed, the combination of the l...

Claims

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Application Information

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IPC IPC(8): H04B17/00
Inventor 李小兵黄一火许昊
Owner ASR MICROELECTRONICS CO LTD
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