Teac Corporation

Hiroshi Usami

Hirohisa Yamaguchi

A magnetic recording/playback apparatus for recording information to a magnetic tape and playing back the information from the magnetic tape, includes first and second recording heads which are provided on a rotary cylinder and alternately record information to the magnetic tape. First and second playback heads are provided on the rotary cylinder at predetermined positions relative to the first and second recording heads, and alternately play back the information from the magnetic tape. A crosstalk canceling switch device cancels crosstalk at outputs of the first and second playback heads when the apparatus is run in a read-after-write mode, the crosstalk canceling switch device being set in a closed position during the read-and-write mode and interconnecting the output of the first playback head and the output of the second playback head.

Magnetic recording/playback apparatus

An optical tracking control apparatus comprises a differential amplifier for differentially amplifying signals respectively reproduced from two mutually adjacent track turns of a guide track on both sides of an intermediate part in which an information signal is recorded and reproduced on and from a disc, a zero crossing detector for detecting a zero crossing of an output signal of the differential amplifier and for producing a switching pulse signal, and a polarity inverting circuit responsive to the switching pulse signal for alternately inverting the polarity of a crosstalk component reproduced from the two mutually adjacent track turns of the guide track as crosstalk for every one-half period of the switching pulse signal. An output signal of the polarity inverting circuit is used as a tracking error signal for controlling the tracking of the light beam.

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Tokyo, Japan

Hiroshi Usami