| 摘要 |
PURPOSE:To confirm the tracking state of a magnetic video recording and reproducing device easily by an interval between a reference line fixed on a reproduced screen and a fluctuating line showing an envelope output, by displaying both the lines by pulses of higher than a white level. CONSTITUTION:An RF signal on a recording track of a magnetic tape 2 is sent from head 1 to envelope detecting circuit 4 to detect a reproduced envelope. A reproduced video signal is applied to terminal 5 and its horizontal synchronizing signal is separated and then applied to tracking pulse generating circuit 7 together with the reproduced envelope output. At a prescribed position in one horizontal Scanning period, the 1st rectangular wave pulse of higher than the white level is generated at the rise of the trailing edge obtained by clipping a trapezoil wave of the horizontal synchronizing signal, having the trailing edge slanted, by the reproduced envelope output, the 2nd rectangular wave pulse of higher than the white level is generated. The 1st and 2nd rectangular wave pulses and the reproduced video signals are mixed to extract the reproduced video signal including tracking pulses. The user can confirm the tracking state easily by looking at the interval on the reproduced screen. |
