Sony Corporation

Makoto Niiro

Daijiro Okihara

Yukio Fukuju

Takao Ohira

Yujio Fukuju

A tape player includes digital and analog reproducing sections for playing back a magnetic tape having recorded thereon encoded digital data arranged in data blocks and an analog signal running parallel to the digital data. A switching circuit in the digital reproducing section includes an error-detecting circuit that indicates the presence of errors or data drop-outs and a width detector that provides an initial error signal when a predetermined consecutive number of data blocks contain errors or are not being reproduced. A decoder provides decoded digital information and a remaining error signal when an uncorrected error is encountered. The remaining error signal is generated with a predetermined delay after the digital data is read from the tape. If the initial error signal is present when the remaining error signal is generated, an AND circuit and a flip-flop in the switching circuit generate a switching signal to substitute the analog signal for the digital signal.

Method and apparatus for reproducing digital or analog signals

An addressing method permits the synchronized reproduction of digitized information recorded on different tapes in different formats, each of which uses a different number of data tracks for each channel of analog information. A first tape uses one track per analog channel. On a second tape each channel is recorded simultaneously in four tracks at one-fourth of the recording speed of the first tape. The data on both tapes is arranged in data blocks that occupy same amount of space. Both tapes have sector intervals occupying a space corresponding to four data blocks, and each sector interval has an associated sector address. On the first tape, the sector addresses in successive intervals are incremented by one, while on the second tape the successive sector addresses are incremented by four. Thus, the data on both tapes can be reproduced in synchronization at their respective recording speeds by maintaining the difference between the sector addresses on the two tapes constant. An apparatus for maintaining synchronized reproduction of two such tapes uses two tape recorders, each of which provides the sector addresses reproduced from the tapes to a subtraction circuit. The digital output of the subtraction circuit represents, in both sense and magnitude, the extent to which synchronization of the playback of the tapes has been lost. A digital-to-analog converter converts the subtraction circuit output into an error signal for controlling the speed of one of the tape recorders.

Method and apparatus for synchronizing playback of tapes recorded in

A video tape recorder includes a rotary magnetic head drum having a rotating member and a magnetic head mounted on the rotating member, a laser element mounted on the rotating member, a current source for supplying a constant current to the laser element, a circuit for electrically connecting a coil of the magnetic head in parallel with the laser element, a photoelectric conversion member fixed in the video tape recorder, and members for optically coupling the laser element with the photoelectric conversion member.

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Sagamihar, Japan

Makoto Niiro