Sony Corporation

Tokihiko Sawashi

Yasuyuki Kino

Koji Kobayashi

Akira Sakamoto

Masahiro Okuno

A data reproduction apparatus includes: arithmetic means for calculating difference data that indicate a difference between left-channel and right-channel data that have been compressed in a predetermined compression format; higher harmonic component generation means for generating a higher harmonic component, which was lost during compression, by performing, when the difference data's signal level exceeds a predetermined threshold, a digital limiter process that suppresses the signal level to the threshold; and adding means for adding the higher harmonic component to the left-channel and right-channel data to reproduce original data before being compressed.

Data reproduction apparatus and data reproduction method

The present invention provides a digital signal processing device that considerably reduces a return noise generated in a processing result signal in specific signal processing without wastefully increasing the processing load. There is provided a digital signal processing device that executes specific signal processing under which a return noise is generated in a processing result signal which includes an up-sampling processing unit that performs the up-sampling processing for a digital signal with a predetermined up-sampling rate to generate an up-sampling signal, a specific signal processing unit that performs the specific signal processing for the up-sampling signal generated by the up-sampling processing unit to generate the processing result signal, and a down-sampling processing unit that performs the down-sampling processing for the processing result signal generated by the specific signal processing unit with a predetermined down-sampling rate to generate a down-sampling signal.

Digital signal processing device, digital signal processing method, and digital signal processing program

A sound field in a vehicle can be further readily and optimally corrected without forcing a user to do troublesome work. As an embodiment of the present invention, a measurement sound emitted through a left speaker or a right speaker at a further position in a view from a driver's listening point that was assumed on the head touching surface of the headrest of the driver's seat or the passenger seat is picked up, with a microphone provided as buried on a front panel of a head unit to be attached to the almost center position between the driver's seat and the passenger seat in the vehicle. And the frequency characteristic of the above sound is corrected, based on a tendency that the frequency characteristic of an audio sound reaching from the left speaker or the right speaker to the microphone is almost approximate to the virtual frequency characteristic of an audio sound that will reach from the left speaker or the right speaker to the driver's listening point assumed on the head touching surface.

Electronic apparatus for vehicle, and method and system for optimally correcting sound field in vehicle

An audio output apparatus includes a masking band determining unit configured to determine a first frequency band in which masking due to environmental sounds is likely to occur in audio signal output sounds; a band-component extracting unit configured to extract a signal component from an input audio signal in the first frequency band determined by the masking band determining unit; a pitch shift unit configured to perform pitch shifting of the signal component in the first frequency band extracted by the band-component extracting unit and generate a pitch shift signal containing a signal component of at least a doubled frequency; and a signal output unit configured to supply an audio signal containing the pitch shift signal acquired by the pitch shift unit to a connected speaker.

Audio output apparatus and audio output method

A sound field measurement apparatus includes a signal generating unit for outputting a burst signal, a driving unit for driving a speaker using the burst signal, a microphone for picking up an audio output from the speaker, an analog-digital converter for performing analog-digital conversion processing on an output signal from the microphone and outputting picked-up audio data, a filtering unit for performing filtering processing on the picked-up audio data, and an analyzing unit for determining a propagation time of the audio output from the speaker to the microphone in accordance with data output from the filtering unit. In this sound field measuring apparatus, the filtering unit is an IIR filter configured to filter the picked-up audio data forward and then backward along a time axis, or an IIR filter configured to filter the picked-up audio data backward and then forward along the time axis.

Apparatus and method for measuring sound field

A power amplification circuit includes first and second clock signal generating portions operable to produce, respectively, first and second clock signals different in frequency from each other; first and second PWM signal generating portions operable to produce first and second PWM signals based on first and second input signals using the first and second clock signals, respectively; a first switching amplifier operable to perform a switching operation in response to the first PWM signal to subject the first PWM signal to power amplification to produce a first output signal and to supply the first output signal to a first circuit load; and a second switching amplifier operable to perform a switching operation in response to the second PWM signal to subject the second PWM signal to power amplification to produce a second output signal and to supply the second output signal to a second circuit load.

Power amplification circuits

A power amplification circuit includes a PWM signal generating portion operable to produce from an input signal first and second PWM signals having complementary variations in their respective pulse widths, a first delaying portion operable to delay the first PWM signal by a first time to produce a first delayed PWM signal, a first switching amplifier operable to perform a switching operation in response to the first delayed PWM signal to subject the first delayed PWM signal to power amplification to produce a first output signal, and to supply the first output signal to a circuit load, a second delaying portion operable to delay the second PWM signal by a second time different from the first time to produce a second delayed PWM signal, and a second switching amplifier operable to perform a switching operation in response to the second delayed PWM signal to subject the second delayed PWM signal to power amplification to produce a second output signal, and to supply the second output signal to the circuit load.

Audio equipment and a method of controlling audio equipment include a switching power amplifier circuit and a controller controlling a switching frequency of the power amplifier circuit. The controller varies the switching frequency of the power amplifier circuit in accordance with a receiving frequency in a case of receiving at least a medium-wave broadcast wave.

Audio equipment and control method of audio equipment

A power amplifier apparatus includes a pair of power amplifiers for performing switching-type power amplification, a transformer, and a capacitor. The transformer is formed of a pair of coils that are connected in series between the corresponding output terminals of the pair of power amplifiers and the corresponding terminals of a speaker. The capacitor is connected in parallel with the output terminals of the pair of coils. With this configuration, a mutual inductance and a leakage inductance are generated in the coils. As a result, 180&deg; out-of-phase and in-phase noise components contained in an output of the power amplifier apparatus can be eliminated.

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Tokyo, Japan

Tokihiko Sawashi