Hitachi, Ltd.

Fujio Okamura

Takashi Furuhata

Takao Arai

Takaharu Noguchi

Keizo Nishimura

Shigemitsu Higuchi

Katsuo Mohri

Yasufumi Yumde

Toshifumi Shibuya

Toshimichi Terada

A coding device in which N digital signals (time-sequential sampled data), obtained by sampling and quantizing analog video signals, are brought together in one group (N being an integer greater than two) and coded. Among these N sampled data, at least one of them serving as a reference is coded with a number of quantization bits n, which is so great that errors due to the quantization can be neglected, and for the other sampled data the difference between the reference sampled data and each of the others is compressed and coded with a number of bits, which is smaller than n. In this way, even if a coding error is produced; effects thereof are restricted within the gorup where it is produced they are not exerted on the other groups, and thus error propagation does not occur.

Compression and coding device for video signals

A method of producing a tracking control signal in a rotary head type magnetic recording and reproducing apparatus and a rotary head type magnetic recording and reproducing apparatus capable of a proper tracking by the use of the tracking control signal. First and second tracking signals are recorded on local portions of each odd-numbered track and the first tracking signal and a third tracking signal are recorded on local portions of each even-numbered track in such a manner that the second tracking signals on two odd-numbered track adjacent to any one even-numbered track are not overlapped with each other and the third tracking signals on two even-numbered tracks adjacent to any one odd-numbered track are not overlapped with each other when viewed in a direction perpendicular to the longitudinal direction of the tracks; upon scanning of a track crosstalk signals are detected from two adjacent track simultaneously with reproduction of the first and second or third tracking signals; and the detected crosstalk signals are compared by the use of timing of the reproduction of the first tracking signal for each track thereby producing a tracking control signal. The second tracking signal may have a frequency equal to that of the third tracking frequency.

Rotary head type magnetic recording and reproducing apparatus and method

Growing community of inventors

Yokohama, Japan

Fujio Okamura