JPS6318880A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To attain the good quality special reproduction without using a head for special reproduction by having a pair of heads and an image memory circuit to synchronize to a head changingover pulse and operate it. CONSTITUTION:A changing-over switch 15 is changed over by a pulse from a gate pulse generating circuit 17, and also for an image memory circuit, the writing and reading of a reproducing image are controlled by the same pulse. A head changing-over pulse generating circuit 18 is connected to the circuit 17, and when the reproduction by one side magnetic head 2a is executed, a gate pulse instructing the memory to the memory 14 is outputted from the circuit 17. Consequently, at the time of the frame feeding reproducing mode, the reproduction output by one side head 2a is written to the memory circuit 14 by the above-mentioned gate pulse, while a head 2b is traced, the switch 15 is changed over to the memory 14 side by the above-mentioned gate pulse and the latest reproducing image of the memory 14 is read. In consequence, the same reproducing output by the head 2a is continuously outputted in a pair, and the excess of the noise bar due to the difference in the azimuth of both heads at the time of the frame feeding reproduction is eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic recording and reproducing apparatus that utilizes an image memory circuit and enables high-quality special reproduction.

[Prior Art] Household magnetic recording and reproducing devices used to record and reproduce video signals usually use a pair of magnetic heads with different azimuths or a helical head that records or reproduces video signals while scanning diagonally across a magnetic tape. It uses a scanning method. Third
The conventional magnetic recording and reproducing apparatus l shown in the figure includes a pair of magnetic heads 2a and 2b for normal reproduction, and one magnetic head 2a for special reproduction such as still image reproduction and frame-by-frame reproduction. A magnetic hept 3 having the same azimuth as the magnetic head 2a is arranged near the other magnetic head 2b, and the configuration is such that during special playback, an image reproduced by one of the magnetic heads 2a and the magnetic head 3 is output.

[Problems to be Solved by the Invention] The above-mentioned conventional magnetic recording and reproducing apparatus I requires a magnetic head 3 for special reproduction in addition to the magnetic heads 2a and 2b for normal reproduction, which inevitably leads to high costs. Moreover, even if the magnetic head 3 for special playback is provided, it does not mean that the noise bars that are inherent in special playback can be completely banished from the screen, and the wear of the magnetic tape 4 increases as the number of magnetic heads increases. There have been problems such as the increase in the number of particles, which tends to impair durability.

[Means for Solving the Problems] The present invention solves the above problems, and a pair of magnetic heads having different azimuths alternately perform oblique scanning on a magnetic tape to record or reproduce signals. The magnetic recording/reproducing device includes: an image memory circuit that operates in synchronization with a head switching pulse that switches between the pair of magnetic heads and stores an image reproduced by one of the magnetic heads; and an image memory circuit that stores an image reproduced by one of the magnetic heads; The present invention is characterized in that it is provided with an image correction means that reads out the image using the next head switching pulse and outputs the image instead of the image reproduced by the other magnetic head.

[Function] The present invention stores an image reproduced by one of the magnetic heads in an image memory circuit that operates in synchronization with a head switching pulse that switches a pair of magnetic heads with different azimuths, and the reproduced image stored by this image memory circuit. is read out by the next head switching pulse and output in place of the image reproduced by the other magnetic head, thereby improving the reproduced image quality during special reproduction.

[Example] Hereinafter, an example of the present invention will be described with reference to FIG. 1.2. FIG. 1 is a schematic circuit diagram showing an embodiment of the magnetic recording/reproducing apparatus of the present invention, and FIG. 2 is a signal waveform diagram of each part of the circuit shown in FIG.

In FIG. 1, only the signal reproducing system for the magnetic tape 4 is shown in the magnetic recording/reproducing device 11, but the video signals read out alternately from the magnetic tape 4 by the pair of magnetic heads 2a and 2b are In the video reproduction circuit 12, the luminance signal is FM demodulated, and the color signal is frequency-converted and then mixed. This video playback circuit 12 has a signal line! 3 and video signal 1
Image memory circuits 14 capable of storing data for one field are connected in parallel, and either the signal line 13 or the image memory circuit I4 selected by the changeover switch 15 is connected to the reproduction output terminal 16. There is. The changeover switch 15 is switched by a gate pulse supplied from the gate pulse generation circuit I7, and the image memory circuit 14 is also controlled to write and read out reproduced images by the same gate pulse. In this embodiment, the changeover switch 15 and the gate pulse generation circuit 17 together constitute an image correction means.

By the way, the gate pulse generation circuit! 7 is connected to a head switching pulse generation circuit +8 which generates a head switching pulse for periodically switching between the negative pair of magnetic heads 2a and 2b, and when one of the magnetic heads 2a is performing reproduction. , a high-level gate pulse that commands the image memory circuit 14 to store data is generated by the gate pulse generation circuit 1.
Output from 7.

Therefore, if the frame-by-frame playback mode is selected now,
One magnetic head 2 of the pair of magnetic heads 2a and 2b
The reproduced output obtained when a is tracing the magnetic tape 4 is written into the image memory circuit I4 by a high-level gate pulse from the gate pulse generation circuit 17. Therefore, the image memory circuit I4 stores the reproduced images one after another, but always updates the stored contents with the latest reproduced image. During the period when the other magnetic head 2b is tracing the magnetic tape 4, the gate pulse generation circuit! Due to the low level gate pulse from 7,
When the changeover switch I5 is switched to the image memory circuit 14 side, the latest reproduced image stored in the image memory circuit 14 immediately before is read out. Therefore, the reproduction output terminal I6 does not contain the reproduction output of the other magnetic hept 2b.
Before that, the reproduction output of the magnetic head 2a tracing the magnetic tape 4 is supplied.

In this way, in the magnetic recording/reproducing device 11, the changeover switch 15 is alternately switched between the video reproducing circuit 12 side and the image memory circuit 14 side, so that the magnetic head 2a always outputs the same reproduction output as shown in FIG. They are output in pairs and can solve the problem of excessive noise bars due to the difference in azimuth between the magnetic heads 2a and 2b during frame-by-frame playback. That is, an image reproduced by one of the magnetic heads 2 is stored in the image memory circuit 14, which operates in synchronization with a head switching pulse for switching a pair of magnetic heads 2a and 2b having different azimuths, and the image memory circuit 14 stores the image reproduced by one of the magnetic heads 2. Since the reproduced image is read out by the next head switching pulse and output in place of the reproduced image by the other magnetic head 2b, the noise bar caused by track crossing during special playback is removed from the magnetic head 2b.
The number of noise bars is reduced from individual to one, and since the position of the noise bar is fixed per still image, the difficulty in viewing is reduced by half, and it can be used for still image playback or frame-by-frame playback where magnetic tape is played slowly. Suitable for special playback.

[Effects of the Invention] As explained above, the present invention stores an image reproduced by one of the magnetic heads in an image memory circuit that operates in synchronization with a head switching pulse that switches between a pair of magnetic heads with different azimuths. Since the reproduced image stored in the image memory circuit is read out by the next head switching pulse and output in place of the reproduced image by the other magnetic head, the noise bar generated by track crossing during special playback is suppressed from the two magnetic heads. I (Ij
Since the position of the noise bar is fixed per still image, the difficulty in viewing is reduced by half, making it suitable for special playback such as still image playback and frame-by-frame playback in which magnetic tape is played while slowly feeding. It has excellent effects such as:

[Brief explanation of the drawing]

FIG. 1 is a schematic circuit configuration diagram showing an embodiment of the magnetic recording/reproducing apparatus of the present invention, FIG. 2 is a signal waveform diagram of each part of the circuit shown in FIG. 1, and FIG. 3 is a diagram of the conventional magnetic recording FIG. 1 is a schematic configuration diagram of main parts showing an example of a playback device. 2a, 2b,..., magnetic head, 4. ,,magnetic tape,I
l., Magnetic recording and reproducing device, 14. ,. Image memory circuit, 15. ,,Selector switch.

Claims (1)

[Claims] A magnetic recording and reproducing device in which a pair of magnetic heads with different azimuths alternately perform diagonal scanning on a magnetic tape to record or reproduce signals, and operates in synchronization with a head switching pulse that switches the pair of magnetic heads. , an image memory circuit for storing an image reproduced by one magnetic head, and an image correction means for reading out the reproduced image stored in this image memory circuit by the next head switching pulse and outputting it in place of the reproduced image by the other magnetic head. A magnetic recording/reproducing device comprising: