Signal processing device and signal processing method

Patent metadata

Field	Value
Publication number	US-9031250-B2
Application number	US-201213462977-A
Country	US
Kind code	B2
Filing date	May 3, 2012
Priority date	Jun 6, 2011
Publication date	May 12, 2015
Grant date	May 12, 2015

Abstract

There is provided a signal processing device s including a noise cancellation process clock generation unit configured to generate a noise cancellation process clock having a predetermined fixed frequency, a noise canceling unit configured to include a noise canceling filter operating based on the noise cancellation process clock and generating a noise canceling signal having a signal property of canceling an external noise component based on an input audio signal including the external noise component picked up by a microphone, and an addition unit superimposing the noise canceling signal generated by the filter on a digital audio signal, and a sampling rate conversion unit configured to rate-convert the input digital audio signal sampled at a clock in asynchrony with the noise cancellation process clock to a signal at a sampling frequency in synchrony with the noise cancellation process clock and to supply the rate-converted signal to the addition unit.

First claim

What is claimed is:

1. A signal processing device comprising:
a noise cancellation process clock generation processor configured to generate a noise cancellation process clock having a predetermined fixed frequency;
a noise canceling processor configured to include a noise canceling filter operating based on the noise cancellation process clock and generating a noise canceling signal having a signal property of canceling an external noise component based on an input audio signal including the external noise component picked up by a microphone,
a sampling rate conversion processor configured to rate-convert the input digital audio signal sampled at a clock in asynchrony with the noise cancellation process clock to a signal at a sampling frequency in synchrony with the noise cancellation process clock; and
an addition processor superimposing the noise canceling signal generated by the filter on the rate-converted digital audio signal;
wherein the sampling rate conversion processor includes:
an up-sampling unit configured to raise the sampling frequency of the input digital audio signal, and
a down-sampling unit configured to lower the sampling frequency raised by the up-sampling unit to a frequency based on the noise cancellation process clock.

2. The signal processing device according to claim 1 ,
wherein the noise canceling processor further includes an external noise digitization processing unit configured to convert the input audio signal including the external noise component picked up by the microphone to a digital signal in synchrony with the frequency of the noise cancellation process clock and to supply the converted digital signal to the noise canceling filter.

3. The signal processing device according to claim 1 , further comprising:
an equalizer unit configured to change a frequency characteristic of the digital audio signal output from the sampling rate conversion processor.

4. The signal processing device according to claim 1 , further comprising:
a supply switching unit configured to switch whether or not the digital audio signal output from the sampling rate conversion processor is supplied to the addition unit.

5. The signal processing device according to claim 1 ,
wherein a digital audio signal component obtained by subjecting the input digital audio signal to a first filtering process is rate-converted by the sampling rate conversion processor, and then the addition unit superimposes the noise cancellation signal on the digital audio signal, and
a digital audio signal component obtained by subjecting the input digital audio signal to a second filtering process is rate-converted by the sampling rate conversion processor, and then an input signal to the filter of the noise cancellation processor is superimposed on the digital audio signal component.

6. The signal processing device according to claim 1 ,
wherein the sampling rate conversion processor rate-converts the input audio signal including the external noise component picked up by the microphone to a signal sampled at a sampling frequency in synchrony with the sampling frequency of the input digital audio signal, and
the signal processing device further comprises:
a signal analysis unit configured to analyze a frequency characteristic of the rate-converted signal; and
a band equalizer configured to change the frequency characteristic of the digital audio signal input based on a result obtained by the signal analysis unit.

7. The signal processing device according to claim 1 ,
wherein the input digital audio signal is a digital audio signal reproduced from a recording medium.

8. The signal processing device according to claim 1 ,
wherein a digital audio signal to be input is a digital audio signal transmitted in a wired or wireless communication manner from an external apparatus.

9. A signal processing method comprising:
generating a noise cancellation signal having a signal property of canceling an external noise component based on an input audio signal including the external noise component picked up by a microphone in a filtering process based on a noise cancellation process clock having a predetermined fixed frequency;
rate-converting an input digital audio signal sampled at a clock in asynchrony with the noise cancellation process clock to a signal having a sampling frequency in synchrony with the noise cancellation process clock; and
adding the noise cancellation signal to the rate-converted digital audio signal;
wherein the rate converting includes raising a sampling frequency of the input digital audio signal and lowering the sampling frequency of the input digital audio signal to a frequency based on the noise cancelation process clock.

Assignees

• Ookuri Kazunobu
• Asada Kohei
• Itabashi Tetsunori
• Sony Corp

Inventors

• Ookuri Kazunobu
• Asada Kohei
• Itabashi Tetsunori

Classifications

• G10K2210/1081

  Earphones, e.g. for telephones, ear protectors or headsets · CPC title

• G10K11/178 Primary

  by electro-acoustically regenerating the original acoustic waves in anti-phase · CPC title

• G10K2210/3051

  Sampling, e.g. variable rate, synchronous, decimated or interpolated · CPC title

• G10K2210/1053

  Hi-fi, i.e. anything involving music, radios or loudspeakers · CPC title

• G10K11/17821 Primary

  characterised by the analysis of the input signals only · CPC title