Systems and methods for noise reduction using sub-band noise reduction technique
A noise reduction system is provided. The noise reduction system may include a sub-band noise sensor, a plurality of sub-band noise reduction modules, and an output module. The sub-band noise sensor may be configured to detect a noise and generate a plurality of sub-band noise signals in response to the detected noise. Each of the plurality of sub-band noise signals may have a distinctive sub-band of the frequency band of the noise. Each of the sub-band noise reduction modules may be configured to receive one of the sub-band noise signals from the sub-band noise sensor and generate a sub-band noise correction signal for reducing the received sub-band noise signal. The output module may be configured to receive the sub-band noise correction signals and output a noise correction signal for reducing the noise based on the sub-band noise correction signals.
1. A system for noise reduction, comprising:
a sub-band noise sensor including a plurality of acoustic-electric transducers and a plurality of sample modules, each of the acoustic-electric transducers having a unique frequency response and being configured to detect a noise and generate a sub-band noise electrical signal by processing the noise, each of the sampling modules being configured to receive one of the sub-band noise electrical signals and sample the received sub-band electrical signal to generate a sub-band noise signal, wherein sampling frequencies of at least two of the sampling modules are different;
a plurality of sub-band noise reduction modules, each of the sub-band noise reduction modules being configured to receive one of the sub-band noise signals from the sub-band noise sensor and generate a sub-band noise correction signal for reducing the received sub-band noise signal; and
an output module configured to receive the sub-band noise correction signals and output a noise correction signal for reducing the noise based on the sub-band noise correction signals.
2. The system of claim 1 , wherein an acoustic-electric transducer of the acoustic-electric transducers comprises:
an acoustic channel component configured to filter the noise to generate a sub-band noise; and
a sound sensitive component configured to convert the sub-band noise into a sub-band noise electrical signal.
3. The system of claim 1 , wherein an acoustic-electric transducer of the acoustic-electric transducers comprises:
a sound sensitive component configured to convert the noise to a sub-band noise electrical signal.
4. The system of claim 1 , wherein
a first acoustic-electric transducer of the acoustic-electric transducers has a first frequency response and is configured to generate a sub-band noise electrical signal corresponding to a first sub-band noise signal of the sub-band noise signals,
a second acoustic-electric transducer of the acoustic-electric transducers has a second frequency response and is configured to generate a sub-band noise electrical signal corresponding to a second sub-band noise signal of the sub-band noise signals, the second sub-band noise signal being adjacent to the first sub-band noise signal among the sub-band noise signals in the frequency domain, and
the first frequency response and the second frequency response intersect at a frequency point which is near at least one of a half-power point of the first frequency response or a half-power point of the second frequency response.
5. The system of claim 4 , wherein the first frequency response of the first acoustic-electric transducer and the second frequency response of the second acoustic-electric transducer have a same frequency bandwidth or different frequency bandwidths.
6. The system of claim 1 , wherein the frequency bands of the sub-band noise signals generated by the sub-band noise sensor cover the frequency band of the noise.
7. The system of claim 1 , wherein at least one sub-band noise reduction module of the sub-band noise reduction modules comprises:
a phase modulator configured to receive the corresponding sub-band noise signal and generate a phase-modulated signal by modulating the phase of the corresponding sub-band noise signal; and
an amplitude modulator configured to receive the phase-modulated signal from the phase modulator and generate the sub-band noise correction signal for reducing the corresponding sub-band noise signal by modulating the amplitude of the phase-modulated signal.
8. The system of claim 7 , wherein the phase modulation of the corresponding sub-band noise signal include an inversion of the phase of the corresponding sub-band noise signal.
9. The system of claim 8 , the phase modulation of the corresponding sub-band noise signal further includes a compensation of a phase displacement of the corresponding sub-band noise signal in its transmission from the sub-band noise sensor to the phase modulator.
10. The system of claim 1 , wherein at least one sub-band noise reduction module of the sub-band noise reduction modules comprises:
an amplitude modulator configured to receive the corresponding sub-band noise signal and generate an amplitude modulated signal by modulating the amplitude of the corresponding sub-band noise signal; and
a phase modulator configured to receive the amplitude-modulated signal from the amplitude modulator and generate the sub-band noise correction signal for reducing the corresponding sub-band noise signal by modulating the phase of the amplitude-modulated signal.
11. The system of claim 10 , wherein the phase modulation of the amplitude-modulated signal includes an inversion of the phase of the amplitude-modulated signal.
12. The system of claim 11 , wherein the phase modulation of the amplitude-modulated signal further includes a compensation of a phase displacement of the corresponding sub-band noise signal in its transmission from the sub-band noise sensor to the phase modulator.
13. The system of claim 1 , wherein:
the noise correction signal includes the sub-band noise correction signals;
the output module includes a plurality of output units, and
each of the output units is configured to receive one of the sub-band noise correction signals generated by the sub-band noise reduction modules and output the received sub-band noise correction signal.
14. The system of claim 1 , wherein the output module is configured to:
receive the sub-band noise correction signals from the sub-band noise reduction modules;
combine the sub-band noise correction signals to generate the noise correction signal; and
output the noise correction signal.
15. The system of claim 1 , wherein the noise include an ambient noise.
16. The system of claim 15 , further comprising:
a residual noise sensor configured to detect a residual noise and generate a residual noise signal in response to the detected residual noise; and
a residual noise reduction module configured to receive the residual noise signal and generate a residual noise correction signal for reducing the residual noise.
17. The system of claim 16 , wherein:
the output module is further configured to receive the residual noise correction signal and output the residual noise correction signal, or
the system further comprises a second output module configured to receive the residual noise correction signal and output the residual noise correction signal.
18. The system of claim 16 , wherein:
the residual noise signal generated by the residual noise sensor includes a plurality of sub-band residual noise signals, and
the residual noise correction signal includes a plurality of sub-band residual noise correction signals, each of the sub-band residual noise correction signals being configured to reduce one of the sub-band residual noise signals.
19. The system of claim 18 , further comprising:
a feedback module configured to adjust the sub-band noise reduction modules according to the residual noise.
20. The system of claim 1 , wherein:
the sub-band noise sensor is mounted near or within the output module, and
the noise includes a residual noise.