JPS60212803A - Correction circuit of magnetic video recording and reproducing device - Google Patents

Abstract

PURPOSE:To prevent flickers of reproduced pictures resulting from the difference in characteristics of video heads so as to improve the quality of pictures, by extracting both band components of FM and side band from the output of the video heads and combining both the band components after their sizes are respectively corrected. CONSTITUTION:The 1st filter 9 is an HPF of >=about 3MHz and extracts FM carrier band components from the output of video heads 1 and 2 and the 2nd filter 10 is an LPF of <=about 3MHz and extracts side band components from the output of the heads 1 and 2. Those outputs are corrected at AGC circuits 11 and 12 and the FM carrier band components outputted from the heads 1 and 2 are made equal to each other in size. The output of the 2nd filter 10 is corrected at the 2nd AGC circuit 2 and the side band components outputted from the heads 1 and 2 are made equal to each other. Moreover, the phases of the FM carrier band and side band components are appropriately corrected at the 1st and 2nd phase correcting circuit 13 and 14 and the both the bands are combined with each other at a combining circuit 15. Therefore, no flicker occurs even at the edge section of reproduced pictures and picture qualities can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a correction circuit for a magnetic recording/reproducing device that improves image deterioration due to differences in characteristics of a plurality of video heads.

[Description of prior art]

In a magnetic recording and reproducing device, a magnetic recording tape is wound approximately half a turn around a rotating head and run at high speed, and two video heads alternately slide into contact with the magnetic recording tape wound around the rotating head to reproduce images. Flickers occur on the playback screen due to differences in the characteristics of video heads. For this reason,
A conventional magnetic recording/reproducing apparatus is provided with a correction circuit as shown in FIG. In FIG. 1, a first channel video head 1 and a second channel video head 2 are alternately switched and selected by a switch 3, and the output of the video head selected by this switch 3 is appropriately amplified by a head amplifier 4. and is applied to the correction circuit 5. This correction circuit 5
consists of an AGC circuit 6 and a phase correction circuit 7, and the AGC circuit 6 corrects the difference in the magnitude of the reproduced output due to the difference in the characteristics of the first and second channel video heads 1 and 2. Furthermore, the phase shift caused by the AGC circuit 6 and the like is appropriately corrected by a phase correction circuit 7, and the resulting signal is provided to a downstream video signal processing circuit (not shown).

Incidentally, the correction by the AGC circuit 6 of the conventional correction circuit 5 described above is based on the magnitude of the FM carrier band component for recording the original video signal on the magnetic recording tape, and the correction is performed by the first and second channel video heads 1. It was intended to correct the magnitude of the output of .2.

Therefore, the sideband band components that are used to transmit the original video signal are not sufficiently corrected for the difference in characteristics between the first and second channel videos.
This caused flickering at the edges of the playback screen, degrading the image quality.

[Summary of the invention]

The present invention has been made to further improve the above-mentioned conventional technology, and the present invention extracts FM carrier band components and sideband band components from the output of a video head, and extracts the extracted FM carrier band components. A correction circuit for a magnetic recording/playback device that corrects the size of the and sideband components and then combines them to prevent flickering on the playback screen caused by differences in video head characteristics and improve image quality. is intended to provide.

[Explanation of Examples]

Hereinafter, embodiments of the present invention will be described with reference to FIG. FIG. 2 is a block circuit diagram showing an embodiment of the correction circuit of the magnetic recording/reproducing apparatus of the present invention. In FIG. 2, the same members as in FIG. 1 are designated by the same reference numerals, and redundant explanations will be omitted.

In FIG. 2, the correction circuit 8 has first and second filters 9 and 10 that receive the output of the head amplifier 4 as input. The first filter 9 consists of a bypass filter that passes a high frequency of about 3 Ml-(z or more, and extracts the FM carrier band component from the output of the video head. A low-pass filter that passes low frequencies below 1-1z extracts sideband components from the output of the video head.Furthermore, the output of the first filter 9 is corrected by the first AGC circuit 11iC. , the FM carrier band components output from the first and second channel video heads 1.2 are set to the same size.The output of the second filter 10 is transmitted to the second AGC circuit 1.
2, and the sideband components output from the first and second channel video heads 1.2 are made to have the same magnitude. Furthermore, the first and second AGC circuits 1
The outputs of 1.12 are phase-corrected appropriately by the first and second phase correction circuits 13.14, respectively, and then sent to the synthesis circuit 15.
The FM carrier band component and the sideband band component are again combined and provided to a subsequent video head signal processing circuit (not shown) K.

Therefore, i@l and the second channel video head 1.
Even if there is a difference in the characteristics of the two, the FM
Obtaining a video head signal in which both the carrier band component and the sight hand band component are corrected to the same magnitude,
and does not cause flickering on the playback screen. Special K
, flicker does not occur even at the edge portions of the playback screen, and the image quality can be improved.

〔Effect of the invention〕

As explained above, according to the correction circuit of the magnetic recording/playback device configured as described above, the FM carrier band component and the sideband band component are each adjusted in each video head in response to the difference in characteristics of a plurality of video heads. Since the configuration is such that correction is made so that the signals have the same magnitude, the magnitudes of the video head signals do not differ due to differences in the characteristics of each video head, and flicker does not occur on the playback screen. In particular, excellent effects such as being able to prevent flickering at the edge portions of the reproduced screen and improving the quality of reproduced images can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a block circuit diagram of a correction circuit of a conventional magnetic recording/reproducing apparatus, and FIG. 2 is a block circuit diagram showing an embodiment of the correction circuit of a magnetic recording/reproducing apparatus of the present invention. In the figure, 1. 1st channel video head, 2
...2nd channel video head, 3 switches,
5, 8...correction circuit, 6-AGC circuit, 9-first filter, 10 second filter, 11 first AGC circuit,
12. Second AGC circuit; 15... Synthesis circuit.

Claims (1)

[Claims] In a magnetic recording/playback device in which an image is formed by switching a plurality of video heads, a first filter extracts an FM carrier band component from the output of the video head, and the output of the first filter is corrected. 1st AGC
a second filter for extracting sideband components from the output of the video head; a second AGC circuit for correcting the output of the second filter; 1. A correction circuit for a magnetic recording/reproducing device, comprising: a synthesis circuit for synthesizing the output of an AGC circuit.