Mitsubishi Electric Corporation

Kosuke Hosoya

Masaru Kimura

Satoru Furuta

Tadashi Yamaura

A frequency band expansion device includes processing circuitry to calculate a weighting coefficient based on a frequency gradient of the input signal; to generate a white noise signal; to generate a first white noise signal by performing filtering on the white noise signal; to generate a second white noise signal by regulating a phase characteristic of the white noise signal; to generate a third white noise signal by performing weighted addition on the first white noise signal and the second white noise signal by using the weighting coefficient; and to generate the output signal by adding together the input signal and a signal corresponding to the third white noise signal, wherein the processing circuitry is configured so that the phase characteristic of the second white noise signal becomes the same as the phase characteristic of the first white noise signal.

Frequency band expansion device, frequency band expansion method, and storage medium storing frequency band expansion program

An audio signal processing apparatus includes; a first correlation component separating unit configured to predict a first signal from a second signal in a predetermined period to generate a first correlation component signal and to separate the first non-correlation component signal from the first signal by using the first correlation component signal; a second correlation component separating unit configured to predict a second signal from the first signal in the predetermined period to generate a second correlation component signal and to separate the second non-correlation component signal from the second signal by using the second correlation component signal; a correlation component synthesizing unit configured to synthesize the first correlation component signal and the second correlation component signal to generate a synthesized correlation component signal; a first gain multiplying unit configured to multiply the synthesized correlation component signal by a gain to generate a correlation component signal; a first signal adding unit configured to add a correlation component signal and a first non-correlation component signal; and a second signal adding unit configured to add the correlation component signal and the second non-correlation component signal.

Audio signal processing apparatus and audio signal processing method

An audio signal processing device includes a high pass filter to convert an input audio signal into a first audio signal and to output the first audio signal, a displacement estimation unit to estimate displacement amplitude of a speaker diaphragm when the input audio signal is inputted, a saturation processing unit to perform saturation processing to the displacement amplitude estimated in the displacement estimation unit or to a signal obtained by correcting the displacement amplitude, an audio signal generation unit to generate a second audio signal by using displacement amplitude obtained after the saturation processing in the saturation processing unit, and an output generation unit to generate an output signal by using the first and the second audio signals. With this configuration, a cracking sound of a speaker is reduced and a user is allowed to feel low frequency components.

Audio signal processing device

An input signal analyzer determines a boundary frequency within the limit of a range which does not exceed a first frequency from the mode of an input signal. A spectrum compressor compresses a power spectrum of frequencies in a band higher than the first frequency in a frequency direction. A gain corrector performs a gain correction on the compressed power spectrum. A spectrum synthesizer reflects the power spectrum outputted from the gain corrector in a band determined by both the first frequency and the boundary frequency. A frequency-to-time converter converts both a synthesized power spectrum provided by the spectrum synthesizer and a phase spectrum of the input signal into ones in the time domain, and outputs these spectra.

Voice emphasis device

A sound source generating unitgenerates from a narrowband audio signal not passing through noise suppression a sound source signal including a fine structure of a band to be restored. On the other hand, a noise suppressing unitperforms noise suppression of the narrowband audio signal and a spectral envelope estimating unitestimates an spectral envelope of the band to be restored. A signal synthesizing unitgenerates a pseudo-audio signal by combining the sound source signal and the spectral envelope, and the band-pass filter unitpasses the pseudo-audio signal of the band to be restored, and the signal addition unitgenerates a broadband audio restoration signal by adding the pseudo-audio signal of the band to be restored to the narrowband audio signal.

Growing community of inventors

Tokyo, Japan

Kosuke Hosoya