Matsushita Electric Industrial Co., Ltd.

Kazuo Kobo

Takashi Yamaguchi

Kiyotake Fukui

Noriaki Morotomi

Takaaki Gyoten

Hidekazu Suzuki

Takeshi Sato

Masashi Kubota

Mikio Sasaki

Toshiro Nozoe

Yutaka Miki

Kazuya Uyeda

Hiroyasu Shinbo

Hidefumi Horiuchi

Robert Ho

A noise reducer for outputting a noise-reduced signal by extracting noise included in an input video signal so as to produce a noise signal and by subtracting the noise signal from the input video signal is provided. The noise reducer includes: a signal processing portion which includes: a delay means for delaying the noise-reduced signal by a predetermined time period thereby outputting a delayed signal; a first subtracter for subtracting the delayed signal from the input video signal thereby outputting a differential signal; an orthogonal transformer for conducting orthogonal transformation on the differential signal, each pixel block of the differential signal being transformed as a unit, thereby outputting an orthogonally transformed signal; a nonlinear processing portion for conducting nonlinear processing on the orthogonally transformed signal based on a predetermined threshold thereby outputting a nonlinear processed signal; an orthogonal inverse transformer for conducting an inverse transformation of the orthogonal transformation on the nonlinear processed signal thereby outputting an inversely transformed signal; an attenuator for attenuating the inversely transformed signal by a predetermined coefficient thereby outputting the noise signal; a second subtracter for subtracting the noise signal from the input video signal thereby outputting the noise-reduced signal; and an adaptive control portion for controlling at least one of the predetermined threshold and the predetermined coefficient based on at least one of the differential signal and the orthogonally transformed signal.

Noise reducer

A waveform equalizing system includes a clock reproducing phase locked loop circuit for reproducing a clock signal from a television signal; a transversal filter; a first selector circuit for alternatively passing the television signal or an output of a first memory to the transversal filter; a CPU for extracting reference signals contained in the television signal from the input and output of the transversal filter through two second memories respectively and for performing a synchronous addition of the same; the first memory for storing a reference signal processed by the synchronous addition; and a second selector circuit for alternatively delivering the television signal or an output of the transversal filter in response to a control signal from the CPU. The CPU is arranged for calculating a phase difference between the clock signal of the clock reproducing circuit and its ideal form from the reference signal processed by the synchronous addition and controlling a clock signal phase of the clock reproducing phase locked loop circuit to correct the phase difference.

Transmitted television signal waveform equalizing system

A ghost canceller includes a ghost cancelling circuit, waveform memories, a CPU, a training signal generating circuit, and a ghost variation detection circuit. By taking in GCR signals from the waveform memories into the CPU, synchronous addition and field sequence processing are effected, and they are transferred to the training signal generating circuit. The input video signal is changed over to the training signal to cancel ghosts, and when ghost variations are is not detected by the ghost variation detection circuit, the input video signal is fed into the ghost cancelling circuit, and is delivered as an output video signal.

Ghost canceller

A ghost cancelling reference signal transmission/reception system, which allows a built-in ghost cancelling device to eliminate group-delay distortion, frequency-amplitude characteristic distortion, ghost components generated in a signal transmission path. A digital signal is superposed on a television signal in a vertical blanking period of the television signal as a ghost cancelling reference signal.

Ghost cancelling reference signal transmission/reception system

A digital data reproducing system which carries out quantization by the frequency over the transmission rate with respect to waveform distortion created by a group delay caused by ghosts and repeaters or the like when digital information signals are received so as to thereby perform waveform equalization, and which carries out phase correction to thereby enable data reproduction about equivalent to that quantized by an ideal sampling timing, thus realizing entire digitization of the data reproducing system.

Digital data reproducing system

Growing community of inventors

Sakai, Japan

Kazuo Kobo