JPS62144481A - Magnetic reproducing device - Google Patents

Abstract

PURPOSE:To obtain the frame still picture of a field signal having the high correlation constantly by advancing a magnetic tape by a prescribed distance and reproducing a video signal of the next frame when the correlation between fields is lost to more than a prescribed level. CONSTITUTION:The difference between a delay signal of one vertical scanning period obtained by inputting the video signal demodulated to a TV signal in a demodulating circuit 6 to a one vertical scanning period delay circuit 7 and the signal which is not passed through the circuit 7 is taken, thereby a difference signal of the signal between the fields is obtained. This difference signal becomes larger as correlation between the fields is smaller. By passing through an LPF8, a local difference in the respective fields can be neglected. When the difference signal becomes to the signal above a fixed level in a level detecting circuit 9, a fixed output is fed, by this output signal, the magnetic tape is advanced by the prescribed distance, to scan the track of the next frame through rotating heads 1, 2, thereby, the video signal of the strong correlation can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is an object of the present invention, in which one field of video signals is recorded on a single magnetic tape tilted with respect to the longitudinal direction of the magnetic tape using magnetic heads with different azimuth angles between adjacent tracks. A magnetic tape on which television signals have been sequentially recorded is scanned using a plurality of rotating heads with different azimuth angles, and two adjacent tracks are scanned by the rotating heads with different azimuth angles, and one frame of stillness is scanned. The present invention relates to a magnetic reproducing device for obtaining a screen.

BACKGROUND OF THE INVENTION FIG. 2 is a schematic %L2. L3. . . . are recording trajectories (tracks) of heads having different azimuth angles, and the inclination angle of the diagonal line in each track indicates the azimuth angle. Adjacent tracks, e.g. R2, L2 . The dotted line shows the trajectory of the rotary head when the track is played back by the rotary head of each azimuth angle.One frame of still screen is obtained by scanning with the rotary head of each azimuth angle as shown by the dotted line. 0 Problems to be Solved by the Invention When attempting to obtain one frame of still screen by scanning with a rotating head at each azimuth angle as shown by the broken line in Figure 2,
During recording, the L2 track is an even numbered track and the R2 track is an odd numbered track, so the signals recorded on the R2) rack and L2 track
It is not necessarily one frame of the original signal when recorded. Therefore, if the original signal is switched to a signal with no correlation at all, the 1-frame video signal obtained by reproducing the R2 and L2 fields will consist of field signals with little correlation and will not work as a still screen. There was a problem. SUMMARY OF THE INVENTION An object of the present invention is to provide a magnetic reproducing device that allows a video signal to be always composed of highly correlated field signals on a still frame screen.

Means for Solving the Problems In order to solve the above-mentioned problems, the magnetic reproducing apparatus of the present invention detects the correlation between each field of the reproduced video signal, and detects the correlation between the fields. , if the loss exceeds a predetermined level, the magnetic tape is advanced a predetermined distance and the video signal of the next frame is reproduced.

Effect: With this configuration, in a frame still screen, it is possible to prevent a video signal from being composed of field signals with little correlation, and it is possible to always obtain a frame still image of field signals with high correlation.

EXAMPLE An example of the present invention will be described below with reference to the drawings.

FIG. 1 shows a block diagram of a magnetic reproducing apparatus in one embodiment of the present invention.

In FIG. 1, 1 is R1°R2,R2 in FIG.
3, . L3. . . . a second rotating head having an azimuth angle for reproducing the tracks; 3.
4 is a head amplifier, 5 is a switch circuit, 6 is a demodulation circuit, 7 is a delay circuit for the vertical scanning period, 8 is a low-pass filter, and 9 is a level detection circuit.

The operation of the magnetic reproducing apparatus of this embodiment configured as described above will be explained below. As shown by the broken line in FIG. 2, when the rotary heads 1 and 2 scan, the rotary head 1
, and 2, the signals of the track R2°L2 that match the azimuth angle of each head are picked up and output as reproduction signals via the head amplifier 3.4. Rotating head 1.
The switch circuit 5 is switched in accordance with the timing of the reproduction signal output of the rotary heads 1 and 2, and the reproduction output signal becomes a continuous signal and is input to the demodulation circuit 6.
The reproduced output signal is demodulated into a television signal. The even and odd fields of the recorded original signal are
Whether it is recorded on tracks R1, R2, R3, . . ., Ll, L2. 1 at the time of recording because it is not specified whether it is recorded on the track L3゜...
The frame is recorded on tracks Ll and R2, and the next frame is recorded on tracks L2. It is also conceivable that it is recorded on track R3.

At this time, the original signal is divided into the frames recorded on tracks Ll and R2, and the frames recorded on tracks L2. Assume that the video is switched between the next frames recorded in the trunk of R3. Rotating head 1. and 2 obtain the reproduced signal by scanning the R2 and L2 tracks, so there is no correlation between the video signals of each field recorded on the R2 and L2 tracks, and the R2,
The video signal obtained by scanning the L2 track has a major visual problem. Therefore, a circuit that detects the correlation between fields is required. One vertical scan J [[
Circuit element, low pass filter8. The circuit constituted by the level detection circuit 9 is an example of an inter-field correlation detection circuit. The video signal demodulated into a television signal by the demodulation circuit 6 is inputted into the vertical scanning period delay circuit 7 to obtain a delayed signal of one vertical scanning period, and - a signal not passed through the vertical scanning period delay circuit 7. By taking the difference between the fields, the difference signal between the signals is obtained. This difference signal becomes larger as the correlation between fields decreases. Here, when the correlation between the video signals is locally lost between fields, this difference signal becomes locally large. Therefore, by passing it through the low-pass filter 8,
Local differences in each field can be ignored. Then, the level detection circuit 9 outputs a constant signal when the signal exceeds a certain level, and uses this output signal to advance the magnetic tape a predetermined distance. , rotating head 1. and 2 to 13. of the next frame. By scanning the L3 track, a video signal with strong correlation between fields can be obtained.

As described above, according to this embodiment, the correlation between fields is detected, and when the correlation between fields is ahead of a predetermined level or more, the magnetic tape is advanced a predetermined distance. By reproducing the signal of the next frame, a magnetic reproducing device is realized that can always obtain frame still images with high correlation.

Effects of the Invention As is clear from the above description, the present invention provides one field of video signal on one track inclined with respect to the longitudinal direction of the magnetic tape, and arranges the azimuth angles of adjacent tracks to be different from each other. Using multiple rotating heads with different azimuth angles, scan a magnetic tape on which television signals are sequentially recorded and scan two adjacent tracks with each rotating head at different azimuth angles to obtain one frame of still screen. A magnetic reproducing device detects the correlation between each field in the reproduced video signal, and if the correlation between the fields is ahead of a predetermined level or more, the magnetic tape is moved a predetermined distance. Since the frame is configured to advance and reproduce the video signal of the next frame, an excellent effect can be obtained in that a frame still screen with high inter-field correlation can always be obtained.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a magnetic reproducing apparatus according to an embodiment of the present invention, and FIG. 2 is a schematic diagram of a track pattern of a magnetic tape on which azimuthal recording is performed. 1.2...Rotating spatula)", 3.4...
Head amplifier, 5...Switch circuit, e...
... Demodulation circuit, 7 ... Vertical scanning period delay circuit, 8 ... Low pass filter, 9 ...
・Level detection circuit, T...magnetic tape, X...
...Scanning direction of the rotating head, Y...Magnetic tape traveling direction during recording, R1, Ll, R2, L2°R3
, L3... Record trajectory of azimuth record 0 Name of agent Patent attorney Toshio Nakao and 1 other person Figure 1

Claims (1)

[Claims] One field of video signals is recorded on one track inclined with respect to the longitudinal direction of the magnetic tape, and a magnetic tape on which television signals are sequentially recorded is arranged on a magnetic tape with different azimuth angles so that adjacent tracks have different azimuth angles. When trying to obtain a single frame still screen by scanning two adjacent tracks with the rotating heads at different azimuth angles using multiple rotating heads, it is necessary to calculate the correlation between each field in the reproduced video signal. A magnetic reproducing device characterized in that when the correlation between fields is detected and the correlation between fields is lost by a predetermined level or more, the magnetic tape is advanced a predetermined distance and the video signal of the next frame is reproduced. .