H
Hiroyoshi Ishikawa
Researcher at Fujitsu
Publications - 104
Citations - 1106
Hiroyoshi Ishikawa is an academic researcher from Fujitsu. The author has contributed to research in topics: Signal & Amplifier. The author has an hindex of 16, co-authored 102 publications receiving 1102 citations.
Papers
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Patent
Distortion compensating apparatus
TL;DR: In this article, a delay time decision unit calculates the correlation between a transmission signal and a feedback signal fed back from the output side of the transmission power amplifier while varying phase difference between both signals.
Patent
Power amplifying apparatus
Hiroyoshi Ishikawa,Nobukazu Fudaba,Hajime Hamada,Yuichi Utsunomiya,Kazuo Nagatani,Toru Maniwa +5 more
TL;DR: In this article, a power amplifying apparatus includes a high-speed low pass filter which inputs an envelope signal included in a transmission signal, a low speed low-pass filter that inputs the envelope signal and determines rising or falling of the signal, and a selecting unit which selects one of the high speed low pass filters and the low speed filter according to a determined result of the determination unit.
Patent
Distortion compensation device
Takayoshi Ode,Yasuyuki Oishi,Tokuro Kubo,Kazuo Nagatani,Hajime Hamada,Hiroyoshi Ishikawa,Nobukazu Fudaba +6 more
TL;DR: In this article, the authors present a distortion compensation device which uses distortion compensation coefficients to subject distortion compensation processing to an input signal and supply the result of the distortion compensated processing to a distorting device, calculating the distortion compensation coefficient based on the input signal before distortion compensation and the feedback signal fed back from the output side of the distorting devices.
Patent
Timing controller and timing control method
TL;DR: In this paper, a timing controller is described that includes an amplifier part, a detector part, and a delay corrector part, each of which is configured to correct the delay of a second input signal in accordance with the timing control signal.
Patent
Activation method of communications apparatus with a non-linear distortion compensation device
TL;DR: In this article, a feedback loop for updating a distortion compensation coefficient is opened and closed, and then the distortion compensation table is generated and after the generation is completed, the operation shifts to the normal operation.