Matsushita Electric Industrial Co., Ltd.

Matsushita Electric Industrial

Ryoji Abe

Masaharu Ikeda

Shin Ito

Herein disclosed is a digital signal processing apparatus comprising: input means for inputting a plurality of acoustic signals from an external outputting device; a plurality of digital signal processing units electrically connected with one another in series to form a closed loop, for receiving and processing said acoustic signals as shared data elements in a sequential order; and output means for outputting a plurality of acoustic data elements processed and generated by said digital signal processing units to an external inputting device, whereby each of said digital signal processing units comprises: receiving means for receiving said shared data elements from a preceding digital signal processing unit; copied data storing means for copying said shared data elements to a shared memory section; acoustic signal processing means for inputting said shared data elements stored in said shared memory section as an input signal, processing said shared data elements thus inputted, and writing an output signal into said shared memory section as shared data elements; transmitting data storing means for storing shared data elements stored in said shared memory section into a transmitting memory; and transmitting means for transmitting said shared data elements stored in said transmitting memory to a subsequent digital signal processing unit.

Digital signal processing apparatus and digital signal processing method

An acoustic feedback suppression apparatus according to the present invention comprises a notch filter () for filtering out acoustic feedback components, a plurality of first sample fast Fourier transformation means (to) for performing frequency analysis of every 512 data samples, a plurality of peak frequency detecting means (to) for detecting peak frequencies of respective channels, adding means () for adding signals on the respective channels, second sample fast Fourier transformation means () for performing frequency analysis of every 4096 data samples of the added signal, peak frequency detecting means () for detecting a peak frequency of the output signal outputted from the 4096 fast Fourier transformation means (), and coefficient specifying means () for specifying filter coefficients of the notch filter ().

Howling suppression device and howling suppression method

Herein disclosed is an audio signal processing apparatus comprising first audio signal processing means for processing an audio signal within a first process time; second audio signal processing means for processing the audio signal within a second process time which is different from the first process time; audio signal delaying means for delaying the audio signal in response to each of the first process time of the first audio signal processing means and the second process time of the second audio signal processing means; selecting means for selectively receiving the audio signals respectively processed by the first and second audio signal processing means; and audio signal outputting means for selectively outputting the audio signal selectively received by the selecting means and the audio signal delayed by the audio signal delaying means.

Audio signal processing apparatus and audio signal processing method

Herein disclosed is a digital filter coefficient setting apparatus which can search and select a specified filter coefficient element corresponding to a specified coefficient parameter inputted by a parameter inputting unit from among the plurality of filter coefficient elements stored in a coefficient storing unit and calculate a specified filter coefficient element on the basis of the specified coefficient parameter when the specified filter coefficient element is not selected from among the plurality of filter coefficient elements stored in the coefficient storing unit, thereby enabling to efficiently set a digital filter in response to a specified filter coefficient element corresponding to any possible specified coefficient parameter inputted therein, as well as to reduce a time required for obtaining the specified filter coefficient element.

Digital filter coefficient setting apparatus and digital filter coefficient setting method

A mute apparatus comprises a plurality of mute switcheseach operative to assume two operation states consisting of a mute-on state and a mute-off state; a mute executing switchoperative to assume two executing states consisting of a mute-on state and a mute-off state; mute switch control data generating meansfor generating mute switch control data elements indicative of the operation states of the respective mute switchesmute switch control data determining meansfor determining whether a mute executing switchis to assume the mute-on or mute-off state on the basis of the mute switch control data elements; and mute switch meansfor having the mute executing switchselectively assume the mute-on and mute-off states on the basis of the mute-on or mute-off state determined by the mute switch control data determining means, thereby making it possible for the single mute switch meansto determine the execution state of the mute executing switchto mute or unmute an audio signal inputted by the inputted terminalon the basis of the operation states of a plurality of the mute switches.

Mute apparatus and mute method

Herein disclosed a volume adjusting apparatus comprising: a plurality of sound inputting terminals for respectively inputting sound elements; a plurality of volume setting means respectively connected with the sound inputting terminals to respectively set volume levels of the sound elements inputted by the sound inputting terminals; and a plurality of sound outputting terminals for respectively outputting the sound elements at the volume levels respectively set by the volume setting means; and volume setting number counting means for counting the number of the active volume setting means; and timer interval calculating means for calculating the time interval on the basis of the number of the active volume setting means calculated by the volume setting number counting means, thereby optimizing the time interval on the basis of the number of the active volume setting means to provides a sufficient response time calculated on the basis of the number of the active volume setting means so that the volume setting means can respectively set the volume levels of the sound elements in accordance with the volume envelope values respectively generated by the volume envelope generating means at the time interval indicated by the timer means.

Volume adjusting apparatus, method and computer program product

A filter device includes a first section for receiving data of a desired cutoff frequency. A second section operates for deciding whether the desired cutoff frequency is in a predetermined low frequency band or a predetermined high frequency band. The predetermined low frequency band is lower in frequency than the predetermined high frequency band. A third section stores data of filter coefficients corresponding to different cutoff frequencies in the predetermined low frequency band. A fourth section stores data of precalculated basic coefficients corresponding to different cutoff frequencies in the predetermined high frequency band. The precalculated basic coefficients are equal to values resulting from a part of calculation to provide final filter coefficients. A fifth section operates for calculating final filter coefficients from precalculated basic coefficients through a coefficient expanding process. In cases where the second section decides that the desired cutoff frequency is in the predetermined low frequency band, data of filter coefficients corresponding to the desired cutoff frequency are read out from the third section, and are set in a filtering section. In cases where the second section decides that the desired cutoff frequency is in the predetermined high frequency band, data of precalculated basic coefficients corresponding to the desired cutoff frequency are read out from the fourth section. Then, the fifth section is caused to calculate final filter coefficients from the read-out precalculated basic coefficients, and data of the calculated final filter coefficients are set in the filtering section.

Filter device and method of acquiring filter coefficients

A common-source type buffer amplifier circuit has a microphone capsule, a diode and an FET. An output end of the buffer amplifier circuit, or a drain of the FET is connected to an input end of the current mirror circuit. An output end of the current mirror circuit is connected to one end of a load resistor of which the other end is grounded. A voltage across the load resistor corresponds to an output of the amplifier and is supplied to the speaker amplifier.

Growing community of inventors

Kanagawa-ken, Japan

Ryoji Abe