Noise signal prediction system
AssigneeMatsushita Electric Industrial Co., Ltd.
InventorsJoji Kane, Akira Nohara
Life of this patent
Estimating the term…
Abstract
A noise signal prediction system includes a signal detector for receiving a mixed signal having a voice signal and a background noise signal and for detecting the presence and absence of the voice signal contained in the mixed signal. A noise level detector is provided for detecting an actual noise level at each sampling cycle during the absence of the voice signal. A storing circuit stores the noise levels for a predetermined number of past sampling cycles. A predicting circuit predicts a noise level of a next sampling cycle based on the stored noise levels in the storing circuit. The storing circuit receiving and stores the actual noise levels during the absence of the voice signal, but stores the predicted noise levels during the presence of the voice signal.
Claims14
A noise signal prediction system comprising:
- a signal detection means for receiving a mixed signal consisting of a wanted signal and a background noise signal and for detecting the presence and absence of said wanted signal contained in said mixed signal;
- a noise level detecting means for detecting an actual noise level at each sampling cycle during the absence of said wanted signal;
- a storing means for storing the noise levels for a predetermined number of past sampling cycles, said storing means receiving and storing said actual noise levels during the absence of said wanted signal;
- a predicting means for predicting a noise level of a next sampling cycle based on said stored noise levels in said storing means;
- wherein said storing means stores said predicted noise levels during the presence of said wanted signal;
- further comprising:
- an attenuation means for attenuating said predicted noise level during the presence of said wanted signal, said attenuation means comprising:
- an attenuation coefficient setting means for setting an attenuation coefficient in response to the detection of the presence of said wanted signal;
- and
- an attenuator connected to said prediction means for attenuating the predicted noise level in accordance with said attenuation coefficient for producing an attenuated predicted noise level during the presence of said wanted signal and for producing a non-attenuated signal in the absence of said wanted signal.
A noise signal prediction system as claimed in claim 2, wherein said attenuation coefficient setting means sets the attenuation coefficient that varies exponentially to gradually increase the attenuation, thereby gradually decreasing the predicted noise level.
A noise signal prediction system as claimed in claim 3, further comprising a band dividing means for dividing said mixed signal into a plurality of bands of frequency ranges and for supplying said divided signals through a plurality of channels.
Dependencies are inferred from the claim text.