| 摘要 |
PURPOSE:To recognize speedily and accurately the position of a defect on a magnetic tape, by reproducing a video signal recorded on the magnetic tape, counting horizontal synchronizing pulses of this video signal and vertical synchronizing pulses of every field respectively, and using counted values of the synchronizing pulses when a dropout occurs as an address signal for showing the position of the defect on the magnetic tape. CONSTITUTION:While a VTR5 is placed in reproduction mode under the command of a microcomputer 6, the video signal is reproduced from the magnetic tape 1 and the reproduced RF signal V is supplied to a dropout detector 10. The detector 10 detects a dropout from a decrease in the amplitude of the reproduced RF signal V and supplies its information to the microcomputer 6 and a dropout width counter 11. When the dropout information is supplied from the detector 10, the microcomputer 6 is further supplied from the current counted values of a V counter 8 and an H counter 9 to store them in a memory together with a counted value from the counter 11. The counted value of V counter 8 shows a recording track where a defect causing the dropout resides and the counted value of the H counter 9 shows the H (horizontal scanning) period wherein the defect on the recording track appears; and those counted values form the address signal showing the position of the defect on the magnetic tape. |
