Sony Corporation

Kazunobu Ohkuri

Toshihiko Masuda

Masaru Shimura

Taro Nakagami

Kohei Asada

Shiro Suzuki

Tetsunori Itabashi

Michiaki Yoneda

Ayataka Nishio

Nobuyuki Yasuda

Hiroki Kawanishi

A noise reduction audio reproducing method includes the steps of: generating, from an audio signal of collected and obtained noise, an audio signal for noise cancellation to cancel the noise by synthesizing the audio signal for noise cancellation and the noise in an acoustic manner, reproducing the audio signal for noise cancellation acoustically to synthesize this with the noise in an acoustic manner; emphasizing an audio component to be listened to, of collected audio; synthesizing an audio signal with the audio component to be listened to being emphasized, and the audio signal for noise cancellation to supply the synthesized signal thereof to an electro-acoustic converting unit; and controlling so as to supply an audio signal, with the audio component to be listened to having been emphasized, to a synthesizing unit, regarding only a section based on a control signal.

Noise reduction audio reproducing device and noise reduction audio reproducing method

A signal processing apparatus includes a first audio output unit configured to output audio of a first audio signal input from a first signal input line, a first pickup unit connected to the first signal input line, a second audio output unit configured to output audio of a second audio signal input from a second signal input line, a second pickup unit connected to the second signal input line, a connecting line that connects the above units to ground, and a first reducing unit configured to at least reduce a first sound leakage signal, being the first audio signal leaking into the second signal input line from the first audio output unit, by using the first audio signal, or reducing a second sound leakage signal, being the second audio signal leaking into the second signal input line from the second audio output unit, by using the second audio signal.

Signal processing apparatus and method

An audio signal processing device includes: a microphone configured to collect noise; an analyzing unit configured to analyze an audio signal collected by the microphone to detect the level and frequency property of the collected audio signal; and a signal processing unit configured to subject an audio signal to be reproduced to signal processing based on the analysis results of the analyzing unit.

Audio signal processing device and audio signal processing method

An audio signal processing apparatus and method for extracting components from an input signal, generating additional components, combining components, and level-controlling components. An audio signal processing apparatus may include a harmonic overtone adder and an equalizer. A harmonic overtone adder may include a high-pass filter, a low-pass filter, an harmonic overtone generator, and a combining unit. An equalizer may include a level detector and a gain controller.

Audio reproducing apparatus

Samples of a component having a frequency less than a predetermined frequency in an input audio signal that is a digital signal having a predetermined sampling frequency are written in a memory. A harmonic-overtone signal having a frequency N times a frequency of the input audio signal is generated by repeating an operation N times, where N is an integer more than one, the operation including reading one sample and thinning out (N&#x2212;1) samples for every N samples from the memory within each cycle period from a first one-direction zero-crossing point to a second one-direction zero-crossing point subsequent to the first one-direction zero-crossing point, each one-direction zero-crossing point being a point at which a level of the input audio signal changes from negative to positive or a point at which the level of the input audio signal changes from positive to negative.

Audio processing method and audio processing apparatus

If the absolute value of the current sample is greater than or equal to an envelope value at the immediately preceding sample, an envelope value at the current sample is made greater than the envelope value at the immediately preceding sample. If the absolute value of the current sample is smaller than the envelope value at the immediately preceding sample and a count value C does not reach a predetermined number N, the count value C is incremented by one and the envelope value at the current sample is held at the envelope value at the immediately preceding sample. If the absolute value of the current sample is smaller than the envelope value at the immediately preceding sample and the count value C reaches the predetermined number N, the envelope value at the current sample is made smaller than the envelope value at the immediately preceding sample.

Bass enhancing method, signal processing device, and audio reproducing system

A signal processing apparatus includes first and second extracting units extracting frequency components having a first frequency band and a second frequency band, respectively, from an input audio signal, a first-harmonic-component generating unit generating a first-harmonic-component signal including a frequency component whose frequency is N1 times that of the frequency component extracted in the first extracting unit, a second-harmonic-component generating unit generating a second-harmonic-component signal including a frequency component whose frequency is N2 times that of the frequency component extracted in the second extracting unit, and a combining unit combining the input audio signal, and the first- and the second-harmonic-component signals in a predetermined ratio. The first frequency band is higher than the second frequency band. N1 and N2 are positive integers, and N1 is smaller than N2.

Signal processing apparatus

Disclosed herein is a signal processing apparatus including: a first decimation processing section for generating, based on a digital signal in a first form, a digital signal in a second form; a second decimation processing section for generating, based on the digital signal in the second form, a digital signal in a third form; a first signal processing section for processing the digital signal in the third form; an interpolation processing section for converting a digital signal in the third form outputted from the first signal processing section into a digital signal in the second form; a second signal processing section for processing the digital signal in the second form outputted from the first decimation processing section; and a combining section for combining the digital signals in the second form outputted from the interpolation processing section and the second signal processing section.

Signal processing apparatus and signal processing method

An audio signal processing apparatus includes a harmonic overtone adder and an equalizer. The harmonic overtone adder includes a high-pass filter for extracting from an audio signal higher than a first predetermined frequency, a filter for extracting a frequency component lower than half a second predetermined frequency, an harmonic overtone generator for generating a frequency-doubled harmonic overtone component from an output from the filter, and a first combining unit for combining the frequency component output from the high-pass filter and the harmonic overtone component output from the harmonic overtone generator. The equalizer includes a level detector for detecting a level of an overtone component contained in an output from the first combining unit, a gain controller for controlling dynamically the level of the harmonic overtone component contained in the output from the first combining unit, and a second combining unit for combining the output from the first combining unit with the harmonic overtone component.

An audio signal processing apparatus includes a high-pass filter for extracting from an audio signal a frequency component higher than f, n band-pass filters for extracting, from the audio signal, frequency components falling within a frequency range from f/N to f/N, n harmonic overtone generators for frequency multiplying each of outputs of the n band-pass filters by N, a first combining unit for combining the generated harmonic overtone components, a level detector for detecting a level of a supplied harmonic overtone component, a gain controller for controlling dynamically the harmonic overtone component supplied from the first combining unit, and a second combining unit for combining the frequency component extracted by the high-pass filter and a harmonic overtone component output from the gain controller, where N is (n being a natural number), fis a first predetermined frequency, and fis a second predetermined frequency higher than f

Disclosed herein is a signal processing apparatus including: analog-to-digital conversion means for performing delta sigma modulation of generating a digital signal having a predetermined sampling frequency and a predetermined quantization bit rate of one or more bits based on an input analog signal; signal processing means including a digital filter having a characteristic for outputting a digital signal having a sampling frequency n&#xd7;Fs (Fs is a reference sampling frequency) and a quantization bit rate of a bits (a is a natural number greater than one) based on the above digital signal; and digital-to-analog conversion means including a part for performing delta sigma modulation for outputting a digital signal having a sampling frequency n&#xd7;Fs and a quantization bit rate of b bits (b is a natural number greater than zero and less than a) based on a digital signal outputted from the signal processing means.

A class-D amplifier has a switching amplifying-unit, which includes a pair of switching elements. The unit drives the switching elements and generates pulse amplified switching signals. The amplifier also has a signal-generating unit, which generates pulse width modulation signals each for driving the switching elements and supplies the generated pulse-width modulation signals to the. switching amplifying-unit. The switching amplifying-unit includes a detecting sub-unit, which detects an operating state of the switching elements. The signal-generating unit includes a dead-time-setting sub-unit, which sets dead time relative to the switching elements by delaying each of the pulse width modulation signals using propagation delay times in logic devices. The signal-generating unit also includes a control sub-unit, which controls the dead-time-setting sub-unit based on a detected result of the detecting sub-unit to change the dead time based on the operating state of the switching elements.

Class-D amplifier

A D/A converter in which distortion caused by PWM is favorably removed even if a sampling frequency is low relative to a signal frequency is provided. The D/A converter includes a pulse-width-modulated-signal outputting circuit for outputting a pulse-width-modulated signal having a pulse width in accordance with a digital value of an input digital signal. A distortion-correcting-component generating circuit () for generating from the input digital signal at least a correcting component corresponding to a distortion component generated in the pulse-width-modulated-signal outputting circuit; a subtractor circuit () disposed at an upstream of the pulse-width-modulated-signal outputting circuit, for subtracting the correcting component generated by the distortion-correcting-component generating circuit from the input digital signal; and a phase correcting circuit () for correcting phase characteristics of the input digital signal so that the distortion component and the correcting component have a phase difference such that these components have opposite phases in the pulse-width-modulated-signal outputting circuit; are provided.

D/A converter and output amplifying circuit

In an audio amplifier having a D-class power amplifier, a noise upon muting is suppressed. A sampling rate converter circuit for sampling rate converting a digital audio signal into a digital audio signal, and a &#x394;&#x3a3; modulation circuit for re-quantizing the digital audio signal into a bit-reduced digital audio signal are provided. Further, a PWM modulation circuit for converting the digital audio signal into a PWM signal, and a D-class power amplifier to which the PWM signal are supplied. Still further, a dither signal forming circuit for superimposing a dither signal SDI on the digital audio signal, and a forming circuit for forming a muting signal SDET are provided. Upon muting, an input side of the sampling rate converter circuit is stopped by the muting signal SDET.

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Kanagawa, Japan

Kazunobu Ohkuri