| 摘要 |
PURPOSE:To perform freely the writing/reading of a retrieving signal without using any exclusive track for retrieval for a helical scan type VTR, by providing a means to control the tracking so that a reproduced envelope is maximum at a vertical blanking part when the retrieving signal is read out. CONSTITUTION:A microcomputer 11 is provided to control the change of the operation mode of a VTR as well as the reading of a retrieving signal, and a sample holding circuit 15 and a comparator 16 are added. First the numerical information recorded previously and corresponding to the recording contents to be retrieved is fed by a ten-key, and then a retrieval start button is pushed. Then a forward or backward high-speed searching mode is set. The same numerical information is written in (n) units of fields (21-20+n) on a magnetic tape. As a result, it is possible to detect either information even in a high-speed searching mode. However, it is impossible to have the normal reading with the signal lacking parts only since the amplitude of a signal envelope is rhombic. Therefore a control is given so that the reproduced envelope output B of the signal lacking part is maximum by applying a tracking error signal TR to a capstan servo circuit. |
