US 4,071,856 AGranted

Servo-control system for signal recording and/or reproducing apparatus

AssigneeSony Corporation

InventorsNobutoshi Kihara, Minoru Morio

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Abstract

In an apparatus for recording and/or reproducing information signals, such as, video signals, on a magnetic tape or other record medium by means of rotary recording and/or reproducing heads which scan successive parallel tracks extending across the tape as the latter is longitudinally advanced: a servo-control system for ensuring accurate scanning of the tracks during reproducing operation includes an auxiliary rotary head repeatedly traversing the tape in coordination with the recording and/or reproducing heads and which, during the recording operation, records pilot signals in areas that are spaced apart along an edge portion of the tape and also traversed by the recording and/or reproducing heads, with each of such areas having an extent in the longitudinal direction of the tape that corresponds, and is in predetermined positional relation to a respective plurality of the successive tracks in which the information signals are being recorded; and, during reproducing operation of the apparatus, a reproduced pilot signal is derived from each of the recording and/or reproducing heads during each traversal by the latter of each area in which a pilot signal is recorded, the levels of the reproduced pilot signals obtained during two different traversals of each area recorded with the pilot signal are compared, and, on the basis of such level comparison, the speed of advancement of the tape is regulated.

In an apparatus for recording and reproducing information signals on a record medium and which includes drive means for advancing the record medium in a predetermined direction during recording and reproducing operations of the apparatus, signal transducing means repeatedly traversing the record medium at a substantial angle to said direction of advancement of the record medium so as to scan successive parallel tracks on the latter, means for applying information signals to said signal transducing means during said recording operation for recording in said successive parallel tracks scanned by said transducing means, and means for deriving reproduced information signals from said signal transducing means when the latter scan said successive parallel tracks during said reproducing operation:

a servo-control system for ensuring accurate scanning of said successive parallel tracks by said signal transducing means during said reproducing operation comprising pilot signal recording means operative during said recording operation of the apparatus for recording uniform pilot signals in areas on the record medium that are spaced apart in said direction of advancement and also traversed by said signal transducing means, with each of said areas having an extent in said direction of advancement that corresponds to the extent in said direction of advancement of a respective plurality of said successive parallel tracks being scanned by said signal transducing means during said recording operation, and with each of said areas further being in a predetermined positional relation, in said direction of advancement, to said respective plurality of parallel tracks;
means operative during said reproducing operation of the apparatus for deriving a reproduced pilot signal from said signal transducing means during each traversal by the latter of each of said areas on the record medium;
means for comparing the reproduced pilot signals derived from said signal transducing means during two different traversals of each one of said areas by said signal transducing means and providing a control signal on the basis of the comparison;
and means responsive to said control signal for regulating said advancement of the record medium relative to the repeated traversing thereof by said signal transducing means.

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Abstract

Claims16