Fujitsu Corporation

Hitoshi Matsuzawa

Yasushi Yamazaki

Masanao Suzuki

Tomonori Sato

Yasuji Ota

Tomohiko Taniguchi

Yoshihiro Tomita

Hiroshi Katayama

Hisanari Kimura

Mutsumi Saito

Chiharu Kawai

In an apparatus which estimates characteristics of a surrounding noise only when an input signal is soundless and performs a noise reduction or suppression of the input signal based on the estimated result, a signal noise ratio is estimated from the input signal, and an automatic switch or an automatic adjustment is performed so as to execute a noise reduction only when the signal noise ratio is good, otherwise to avoid the noise reduction or make the noise reduction degree smaller.

Noise suppressing apparatus

An echo canceler makes it possible to adaptably control a power of speech reception voice and to reduce distortion of a voice output from a speaker. The echo canceler has a basic structure includes a power control section controlling a power for a speech reception voice, a first filtering section removing a particular component from an output of the power control section, an echo canceling section removing echo components of a speech reception voice, which are added to a speech transmission voice, a second filtering section filtering particular components of the speech reception and transmission voices, and a state judgement section judging existences of the speech reception and transmission voices from an output of the second filtering section and controlling a power attenuation amount of the power control section based on the judgement result.

Echo canceler

In an active noise control method of the present invention, a noise detection signal from a noise referring microphone which detects ambient noise is inputted into noise processing units of different types to produce noise silencing signals. A selected noise silencing signal is inputted into a receiver or a speaker together with a reception signal via an adder, so that a regenerated tone from the noise silencing signal silences the ambient noise, When a nonconformance detecting unit judges that the selected noise silencing signal exceeds a predetermined range, the corresponding noise processing unit is judged to be incompatible, and a switch control unit controls a switch to select another one of the noise processing units.

Active noise control method and receiver device

Speech encoding using searching of a code book for a code that matches an input speech signal, and speech decoding using the code book are disclosed. A random series of code samples is stored in a buffer memory such as a ring buffer memory, and a basic vector generation unit generates basic vectors by applying an arbitrary shift to each of code series retrieved from the random series. Generation of the basic vectors may be performed according to, for example, an overlapping vector generation process. A code book generation unit extends the basic vectors contained in a basic vector unit according to a structuring process so as to produce a tree-structured delta code book. The basic vector generation unit may extend the basic vectors based on pitch parameters or a center clipping threshold.

Speech encoding and decoding method and speech encoding and decoding

Speech processing coder, decoder and command recognizer

Growing community of inventors

Kawasaki, Japan

Hitoshi Matsuzawa