1
Tatsumasa Yoshida, Ryoichi Miyamoto, Masashi Takada, Katsuya Suzuki: Adaptive noise canceller. Oki Electric, Christopher H Lynt, Spencer Frank & Schneider, December 5, 1995: US05473702 (96 worldwide citation)

An adaptive filter estimates the noise component in a primary audio signal by convolving a secondary audio signal with a set of coefficients. The estimated noise component is subtracted from the primary audio signal to produce an output signal. During steady-state operation, the adaptive filter coef ...


2
Yoshio Masuda, Atsushi Fukasawa, Takuro Sato, Tatsumasa Yoshida, Hiromi Ando: High frequency filter. Oki Electric, Armstrong Nikaido Marmelstein & Kubovcik, May 31, 1983: US04386328 (20 worldwide citation)

A high frequency filter for frequencies higher than the VHF band comprising of a closed conductive housing (53), a pair of input and/or output means (54) like an antenna provided at both the extreme ends (53-5, 53-6) of said housing (53), a plurality of resonators (51-1 through 51-5, and 51a-1 throu ...


3
Tatsumasa Yoshida, Masashi Takada: Method and apparatus for echo cancelling with multiple microphones. Oki Electric, Michael A Sartori, Venable, June 11, 2002: US06404886 (18 worldwide citation)

An echo canceling apparatus has two microphones, both receiving an acoustic signal including a near-end speech component and an echo component. A first adaptive filter cancels the echo component in the output of the first microphone, obtaining a first residual signal. A second adaptive filter cancel ...


4
Masashi Takada, Tatsumasa Yoshida: Radio receiver. Oki Electric, Norman N Kunitz, Venable, November 12, 2002: US06480722 (4 worldwide citation)

Radio receivers which switches the received voice signal according to a supervisory signal used for supervising the condition of the propagation path through which the voice signal is transmitted are known. However, if the reception level of the radio wave received by a conventional radio receiver i ...


5
Tatsumasa Yoshida, Ryoichi Miyamoto: Angular modulator with a phase variation divided and integrated. Oki Electric, Rabin Champagne & Lynt P C, May 12, 1998: US05751198 (3 worldwide citation)

A digital modulator capable of obtaining a high FM modulation index and reducing the quantization noise without increasing the sampling frequency of an A/D converter of input voice. A phase variation .phi.(Ts) of the digital data (Ts is the sampling period) produced on the basis of the output from t ...


6
Tatsumasa Yoshida, Ryoichi Miyamoto: Angular modulator with a phase variation divided and integrated. OKI Electric, Rabin & Champagne P C, May 18, 1999: US05905413 (3 worldwide citation)

A digital modulator capable of obtaining a high FM modulation index and reducing the quantization noise without increasing the sampling frequency of an A/D converter of input voice. A phase variation .phi.(Ts) of the digital data (Ts is the sampling period) produced on the basis of the output from t ...


7
Tatsumasa Yoshida: Frequency modulation method and frequency modulated signal transmitter. Oki Electric, Rabiin & Champagne P C, March 27, 2001: US06208845 (2 worldwide citation)

A frequency-modulated signal transmitter and frequency modulation method are provided wherewith the linearity of an FM modulated signal is secured even when the level of frequency modulation after FM modulation is low. A level-subtraction circuit