US 5,499,144 A · Magnetic recording/playback apparatus which shifts the head scan by a 1/2 t r

Abstract

In a magnetic recording/playback apparatus for recording and playing back a digital video signal on a helical track of a magnetic tape using two or more rotary heads, the playback image at the time of high-speed playback is improved by setting the tape travel speed at the time of high-speed playback at an even multiple of a normal playback speed. Further a tracking phase is offset by one half the track pitch with respect to the tracking during normal speed playback. Alternatively, essential information of the information having been high-efficiency coded is recorded in the central part, and near the ends of the tracks, while high-precision information is recorded in intermediate parts intermediate between the central part and the parts near the ends. Still alternatively, the video data of one of the consecutive fields is recorded in the central part of the tracks and the video data of the other of the consecutive fields is recorded near the ends of the tracks.

Claims12

Dependent claims

A magnetic playback apparatus for playing back digital video signals recorded on helical tracks on a magnetic tape using at least two rotary heads, comprising:

rotary speed control means for controlling a rotary speed of a rotary head;
tape travel and tracking control means for controlling the speed of magnetic tape travel and controlling a tracking phase at a beginning of tracking on the magnetic tape by the rotary heads;
and
a control circuit for selectively causing one of normal playback and high-speed playback, and for providing a 1/2 track-pitch offset command to said tape travel and tracking control means at a time of selectively caused high speed playback;
said tape travel and tracking control means, in response to said 1/2 track-pitch offset command, offsetting the lateral position of the rotary head relative to the track by a 1/2 track-pitch from the lateral position of the rotary head relative to the track during normal playback, at a beginning of tracking on the magnetic tape,
the tape travel speed during the high speed playback being set substantially at (4n+2) times a normal playback speed, n being an integer not smaller than zero.

3 more elements

A playback method for reproducing digital video signals recorded in helical tracks on a magnetic tape using at least two rotary heads of a magnetic tape reproduction apparatus, comprising the steps of:

(a) controlling, selectively, a rotary speed of the rotary heads to be one of a normal playback speed and a high-speed playback speed;
(b) controlling traveling speed of the magnetic tape to be set substantially at (4n+2) times normal playback speed in response to the rotary speed selectively controlled to be a high-speed playback speed in step (a), n being an integer not smaller than zero;
(c) controlling a tracking phase at a beginning of tracking on the magnetic tape by the rotary heads;
(d) offsetting the tracking phase of the rotary heads by a one-half track pitch from a tracking phase of the normal playback speed, in response to the rotary speed selectively controlled to be a high-speed playback speed in step (a);
and
(e) reproducing the digital video signals by tracking the rotary heads, with the lateral position of the rotary head offset relative to the track by a one-half track pitch, from the lateral position of the rotary head relative to the track during normal playback, at a beginning of tracking on the magnetic tape.

3 more elements

A playback apparatus for reproducing digital video signals recorded in helical tracks on a magnetic tape using at least two rotary heads, comprising:

controller for controlling, selectively, a rotary speed of at least one of the rotary heads to be one of a normal playback speed and a high-speed playback speed;
tape travel speed controller for controlling traveling speed of the magnetic tape to be set substantially at (4n+2) times normal playback speed in response to the rotary speed being selectively controlled to be a high-speed playback speed, n being an integer not smaller than zero;
and
reproducing means, including at least one of the rotary heads, for reproducing the digital video signals by tracking at least one of the rotary heads, with the lateral position of at least one of the rotary heads being offset relative to the track by a one-half (1/2) track pitch from the lateral position of the rotary head relative to the track during normal playback speed at a beginning of tracking on the magnetic tape,
said offset being effected in response to the rotary speed being selectively controlled to be a high-speed playback speed.

2 more elements

Dependencies are inferred from the claim text.

Magnetic recording/playback apparatus which shifts the head scan by a 1/2 t r

Life of this patent

Magnetic recording/playback apparatus which shifts the head scan by a 1/2 t r

Life of this patent

Abstract

Claims12