Matsushita Electric Industrial Co., Ltd.

Todd S Bowser

Seiji Sakashita

Hiroaki Ozeki

Ippei Kanno

Daisuke Hayashi

Shuji Inoue

Sadashi Kageyama

Kenichiro Hayashi

Hideyo Uwabata

Yoshio Yasumoto

A digital signal error reduction apparatus of the present invention tracks and reduces both quickly changing errors and static errors in a digital signal which are caused by time variant multipath distortion, co-channel interference, and other transmission path interferences, including nonlinear distortion. A transversal filter is implemented for filtering the digital signal. A error detection device is implemented for calculating an error of the digital signal. A coefficient engine device is used for receiving the digital signal and the error, for extracting the error, and for updating a tap coefficient for the transversal filter so that the error is minimal.

Digital signal error reduction apparatus

A forward error correcting transmitter and receiver for preventing the erroneous detection of synchronization is provided in a system in which synchronization of an interleaver circuit and a deinterleaver circuit, to be inserted between a convolutional encoder and a Viterbi decoder, is obtained from a synchronization detecting circuit of the Viterbi decoder. A LFSR (Linear Feedback Shift Register) is used as a row-direction address counter during writing and an up/down counter is used as a column-direction address counter during reading, during the interleaver circuit. In the deinterleaver circuit, an up/down counter is used as the column-direction address counter during writing, and an LFSR is used as the row-direction address counter during reading.

Forward error correcting transmitter and receiver

In the television broadcasting system called letter box method, it is proposed to transmit an image having a larger aspect ratio than that of the existing broadcasting system by using some of the scanning lines of the existing broadcasting system, and transmit some additional information signal in the remaining portion. An offset value applied to the additional information signal at the transmission side must be removed completely at the reception side. Accordingly, at the reception side, in the scanning line in which an offset reference signal indicative of the offset value is transmitted, the offset reference value and a DC level reference value of the scanning line are detected, and these values are retained until a next offset reference signal is detected. By detecting a DC level of a scanning line containing the additional information signal, a difference from the DC level reference value previously detected and retained is obtained, and the offset reference value detected and retained previously is corrected by this difference. Thus obtained offset value is subtracted from the transmitted additional information signal.

Television signal processing apparatus for separating an auxiliary

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Itami, Japan

Todd S Bowser