CN113160841A

CN113160841A - Digital noise reduction electronic circuit and electronic device

Info

Publication number: CN113160841A
Application number: CN202110233335.8A
Authority: CN
Inventors: 黎小辉; 谭贵勇
Original assignee: Guangzhou Lango Electronic Science and Technology Co Ltd
Current assignee: Guangzhou Lango Electronic Science and Technology Co Ltd
Priority date: 2021-03-02
Filing date: 2021-03-02
Publication date: 2021-07-23

Abstract

The invention discloses a digital noise reduction electronic circuit, which comprises an input module, an analog-to-digital converter, a sampling filter, a first filter, a second filter, a digital-to-analog converter and an output module which are connected in sequence; the input module is used for inputting sound analog signals; the analog-to-digital converter is used for converting the received sound analog signal into a digital signal; the sampling filter samples the digital signal to obtain a sample signal; the first filter is used for carrying out filtering processing on the sample signal to obtain a filtered signal; the second filter is used for generating an interpolation signal from the filtering signal through interpolation filtering; the digital-to-analog converter is used for generating a noise elimination signal from the interpolation signal; the output module outputs the noise cancellation signal. In addition, the invention also provides electronic equipment. The digital noise reduction electronic circuit and the electronic equipment provided by the invention are easy to improve the time delay adjustment accuracy in the noise reduction process.

Description

Digital noise reduction electronic circuit and electronic device

Technical Field

The invention relates to the technical field of digital noise reduction electronic circuits, in particular to a digital noise reduction electronic circuit and electronic equipment.

Background

At present, as the mobile phone uses an earphone or a sound box to play audio, the earphone or the sound box becomes mainstream, and the earphone or the sound box is connected to the mobile phone through a connecting line to listen to sound, or connected to the mobile phone through bluetooth, so that the mobile phone can listen to conversation sound and audio and video playing sound generated by the mobile phone through the earphone or the sound box. However, when the earphone or the sound box is used for listening to audio, the earphone or the sound box is easily influenced by environmental noise, and in order to avoid the influence of the environmental noise, some earphones are packaged, namely, the loudspeaker of the earphone is packaged by the shell to cover the earphone on the ear. In addition, some earphones or sound boxes use an inverse playing mode, playing output is influenced by an inverse playing method according to environmental noise fed back by environmental sound, but a more significant limitation is added to a frequency range capable of realizing noise reduction, so that the realization is difficult or poor in effect, and the available frequency range of the earphones is reduced.

Disclosure of Invention

The invention provides a digital noise reduction electronic circuit and electronic equipment, and aims to solve the existing noise reduction problem by providing the digital noise reduction electronic circuit to realize noise reduction.

In order to achieve the above object, the present invention provides a digital noise reduction electronic circuit, which comprises an input module, an analog-to-digital converter, a sampling filter, a first filter, a second filter, a digital-to-analog converter and an output module, which are connected in sequence; the input module is used for inputting sound analog signals; the analog-to-digital converter is used for converting the received sound analog signal into a digital signal; the sampling filter samples the digital signal to obtain a sample signal; the first filter is used for carrying out filtering processing on the sample signal to obtain a filtered signal; the second filter is used for generating an interpolation signal from the filtering signal through interpolation filtering; the digital-to-analog converter is used for generating a noise elimination signal from the interpolation signal; the output module outputs the noise cancellation signal.

Preferably, the input module includes a first speaker and a microphone disposed near the first speaker, the microphone being configured to detect sound and ambient noise generated by the first speaker.

Preferably, the microphone outputs the sound analog signal.

Preferably, the sampling filter comprises a low pass filter and/or a sampler.

Preferably, the first filter is a digital signal filter.

Preferably, the second filter is an interpolation filter.

Preferably, the output module includes a second speaker, and the digital-to-analog converter is coupled to the second speaker to output the noise cancellation signal to the second speaker.

Meanwhile, the invention provides an electronic device comprising the digital noise reduction electronic circuit.

According to the digital noise reduction electronic circuit and the electronic equipment, the noise elimination signal is obtained by carrying out sampling filtering, digital filtering and interpolation filtering on the input sound analog signal, the digital noise reduction purpose is achieved by using the noise elimination signal, meanwhile, amplitude and phase response required by noise reduction is more accurately realized based on the processing of the digital signal than an actual analog circuit, and the time delay adjustment accuracy in the noise reduction process is easy to improve.

Drawings

Fig. 1 is a schematic structural diagram of a digital noise reduction electronic circuit according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1, in an embodiment of the present invention, the digital noise reduction electronic circuit includes an input module 10, an analog-to-digital converter 20, a sampling filter 30, a first filter 40, a second filter 50, a digital-to-analog converter 60, and an output module 70, which are connected in sequence; the input module 10 is configured to input a sound analog signal, the input module 10 includes a first speaker 11 and a microphone 12 disposed near the first speaker 11, the microphone 12 is configured to detect sound and environmental noise generated by the first speaker 11, the microphone 12 outputs the sound analog signal, and the sound analog signal includes sound and environmental noise generated by the first speaker 11 and detected by the microphone 12. The analog-to-digital converter 20 is configured to convert the received sound analog signal into a digital signal; the next filtering processing is carried out based on the digital signals, and compared with an analog circuit or an analog signal, the filtering processing of the digital signals is more accurate, repeatable, relatively stable, more convenient and more convenient to process the digital signals, hardware cost can be saved, and control can be carried out.

The sampling filter 30 samples from the digital signal to obtain a sample signal; in particular, in an embodiment of the present invention, the sampling filter 30 includes a low pass filter and/or a sampler, the low pass filter is mainly used for high frequency or high frequency elimination; the sampling filter 30 identifies the higher frequency signal and performs a preliminary treble elimination, low pass filtering the digital signal and regenerating a sample signal of the audio with an acceptable signal-to-noise ratio.

The first filter 40 is configured to perform filtering processing on the sample signal to obtain a filtered signal; the first filter is a digital signal filter. The first filter 40 performs an operation process on the digital code of the input sample signal to achieve the purpose of changing the signal spectrum. Specifically, in an embodiment of the present invention, the first filter 40 performs 16-bit or 24-bit digital information processing. The processing of the sample signal by the first filter 40 to generate a filtered signal to achieve the roll-off noise cancellation effect at higher frequencies in conjunction with the sampling filter 30.

The second filter 50 is used for generating an interpolation signal from the filtering signal through interpolation filtering; the second filter 50 is an interpolation filter, and in particular, in an embodiment of the present invention, the filtered signal is further processed by the second filter 50, and since the filtered signal is a digital signal, interpolation is required to perform more accurate simulation due to speed inconsistency within a specified time, and a typical method is linear interpolation, that is, interpolation between discrete digital signal points. Specifically, 0 is inserted between the digital signals of the original announcement, and the digital signals after 0 insertion are processed by a filter to output an interpolation signal.

The digital-to-analog converter 60 is used for generating a noise elimination signal from the interpolation signal; the output module 70 outputs the noise cancellation signal. The output module 70 includes a second speaker, and the digital-to-analog converter 60 is coupled to the second speaker to output the noise cancellation signal to the second speaker.

The digital noise reduction electronic circuit provided by the invention provides a noise reduction effect with higher noise reduction degree by using a low-latency signal processing chain consisting of analog-to-digital conversion, digital processing and digital-to-analog conversion.

Furthermore, the invention provides an electronic device comprising a digital noise reduction electronic circuit as described above.

Compared with the prior art, the digital noise reduction electronic circuit and the electronic equipment provided by the invention have the advantages that the noise elimination signal is obtained by carrying out sampling filtering, digital filtering and interpolation filtering on the input sound analog signal, the digital noise reduction purpose is achieved by using the noise elimination signal, meanwhile, the amplitude and phase response required by noise reduction is more accurately realized based on the processing of the digital signal than an actual analog circuit, and the time delay adjustment accuracy in the noise reduction process is easy to improve.

While the foregoing is directed to embodiments of the present invention, it will be understood by those skilled in the art that various changes may be made without departing from the spirit and scope of the invention.

Claims

1. A digital noise reduction electronic circuit is characterized by comprising an input module, an analog-to-digital converter, a sampling filter, a first filter, a second filter, a digital-to-analog converter and an output module which are sequentially connected; the input module is used for inputting sound analog signals; the analog-to-digital converter is used for converting the received sound analog signal into a digital signal; the sampling filter samples the digital signal to obtain a sample signal; the first filter is used for carrying out filtering processing on the sample signal to obtain a filtered signal; the second filter is used for generating an interpolation signal from the filtering signal through interpolation filtering; the digital-to-analog converter is used for generating a noise elimination signal from the interpolation signal; the output module outputs the noise cancellation signal.

2. The digital noise reduction electronic circuit of claim 1, wherein the input module comprises a first speaker and a microphone disposed proximate the first speaker, the microphone configured to detect sound generated by the first speaker and ambient noise.

3. The digital noise reduction electronic circuit of claim 2, wherein the microphone outputs the acoustic analog signal.

4. Digital noise reduction electronic circuit according to claim 1, wherein the sampling filter comprises a low pass filter and/or a sampler.

5. The digital noise reduction electronic circuit of claim 1, wherein the first filter is a digital signal filter.

6. The digital noise reduction electronic circuit of claim 1, wherein the second filter is an interpolation filter.

7. The digital noise reduction electronic circuit of claim 1, wherein the output module comprises a second speaker, the digital-to-analog converter coupled to the second speaker to output the noise cancellation signal to the second speaker.

8. An electronic device, characterized in that it comprises a digital noise reduction electronic circuit according to any of claims 1 to 7.