| 摘要 |
PURPOSE:To enable to detect the dropout in all levels to the length of detected length, by repeating the hold of peak value of playback signal, threshold level processing and reset operation, with the peak holding circuit every one wavelength of playback signal. CONSTITUTION:One playback signal S from the head 6 of the magnetic tape 5 passes through the amplifier 7, triggers the D type flip-flop 13 as the pulsed signal with the pulsating circit 8, oscillation output signal with the phase locked loop circuit 10 and trigger signal with the monostable multivivrator 11, and reseds the peak holding circuit 9 as the reset signal with the monostable multivibrator 12. Another signal S is inputted to the circuit 9 directly, the peak value of the signal S from the circuit 9 is fed to the comparator 14 to be compared with the threshold level, and high- or low-level signal is fed to the flip-flop 13 and after obtaining respective output from the output terminal, the circuit 9 is reset with the said reset signal, the peak value is sequentially stored and each peack value is compared with the threshold level. |
