KR960025564A

KR960025564A - Head switching device for 4-head video cassette recorder

Info

Publication number: KR960025564A
Application number: KR1019940038609A
Authority: KR
Inventors: 이주현
Original assignee: 배순훈; 대우전자 주식회사
Priority date: 1994-12-29
Filing date: 1994-12-29
Publication date: 1996-07-20

Abstract

본 발명은 헤드 드럼에 제1, 제2우 및 좌 헤드가 장착되어 있는 VCR의 특수 재생 모드를 제어하기 위한 회로로서, 제1스위칭 신호에 따라 스위칭 되어 제1우 및 제1좌 헤드에 의하여 독취된 자기 테이프의 영상 신호를 선택적으로 출력하는 제1스위치와; 제2스위칭 신호에 따라 스위칭 되어 제1좌 및 제2우 헤드에 의하여 독취된 자기 테이프의 영상 신호를 선택적으로 출력하는 제2스위치와; 제3스위칭 신호에 따라 스위칭되어 상기 제1 및 제2스위치로부터 출력되는 신호를 선택적으로 출력하는 제3스위치와; 입력 영상 신호를 디스플레이할 수 있도록 처리하여 출력하는 영상처리 회로와; 상기 헤드 드럼의 PG 펄스의 반주기 마다 상기 제3스위치의 스위칭을 절환시키는 제3스위칭 신호를 출력하므로서 상기 제1 및 제2스위치의 출력을 선택적으로 상기 영상처리 회로에 인가하며, 상기 특수 재생 모드시에 상기 제1, 제2우 및 좌 헤드가 접촉하는 자기 테이프의 트랙이 변경되는 변경 시간이 저장되어 있으며, 상기 변경 시간마다 상기 제1 및 제2스위칭 신호를 선택적으로 출력하여 상기 제1,2우 및 좌 헤드와 자기 테이프의 아지머스각이 일치될 때의 영상 신호가 상기 제3스위치에 인가되게 하는 제어 회로를 구비한다.The present invention is a circuit for controlling a special playback mode of a VCR in which a head drum is equipped with first, second right and left heads, and is switched according to a first switching signal and read by the first right and first left heads. A first switch for selectively outputting a video signal of the magnetic tape; A second switch switched according to the second switching signal to selectively output an image signal of the magnetic tape read by the first left and second right heads; A third switch switched according to a third switching signal and selectively outputting signals output from the first and second switches; An image processing circuit which processes and outputs an input image signal so as to be displayed; Selectively outputting the outputs of the first and second switches to the image processing circuit by outputting a third switching signal for switching the switching of the third switch every half cycle of the PG pulses of the head drum. The change time at which the tracks of the magnetic tapes in contact with the first, second right and left heads are changed is stored, and the first and second switching signals are selectively output at each change time to the first and second switches. And a control circuit for causing a video signal to be applied to the third switch when the azimuth angles of the right and left heads and the magnetic tape coincide.

즉, 본 발명은 4 헤드 방식의 VCR에서 헤드의 출력을 선택하는 기준은 종래와 같이 헤드에 의하여 독출된 영상 신호의 엔벨로프 파형이 아니라 드럼 모터의 PG 펄스를 분주한 시간 값이 되는 것이다. 따라서, 본 발명은 헤드에 의하여 독출된 영상 신호의 엔벨로프 파형이 큰 차이가 나지 않을 경우가 발생하는 채터링(Chattering) 현상을 예방할 수 있다는 효과가 있다.That is, in the present invention, the criterion for selecting the output of the head in the four-head VCR is a time value obtained by dividing the PG pulse of the drum motor, not the envelope waveform of the video signal read out by the head as in the related art. Therefore, the present invention has the effect of preventing the chattering phenomenon that occurs when the envelope waveform of the image signal read out by the head does not have a large difference.

Description

Head switching device for 4-head video cassette recorder

본 내용은 요부공개 건이므로 전문내용을 수록하지 않았음Since this is an open matter, no full text was included.

제3도는 본 발명에 따른 4 헤드방식 비데오 카세트 레코더의 헤드 절환 장치의 동작 상태를 설명하는 도면.3 is a view for explaining an operation state of a head switching device of a four-head video cassette recorder according to the present invention.

Claims

A circuit for controlling a special playback mode of a video cassette recorder in which a head drum is equipped with first, second right and left heads, which is switched in accordance with a first switching signal and read by the first right and second left heads. First switching for selectively outputting a video signal of the magnetic tape; A second switch switched according to the second switching signal to selectively output an image signal of the magnetic tape read by the first left and second right heads; A third switch switched according to a third switching license and selectively outputting signals output from the first and second switches; An image processing circuit which processes and outputs an input image signal so as to be displayed; Selectively outputting the outputs of the first and second switches to the image processing circuit by outputting a third switching signal for switching the switching of the third switch every half period of the PG pulse of the head drum. The change time at which the track of the magnetic tape contacting the first, second right and left heads is changed is stored, and the first and second selectively outputting the first and second switching signals at each change time. And a control circuit for causing a video signal to be applied to the third switch when the right and left heads and the azimuth angle of the magnetic tape coincide with each other.

※ Note: The disclosure is based on the initial application.