MAGNETIC TAPE RECORDER AND REPRODUCING DEVICE

摘要

PURPOSE:To realize a stable searching picture even in the transient period of tape running at the time of searching with a simple circuit, by continuously controlling the rotating speed of a cylinder motor provided with a recording and reproducing means with electric potential proportional to the frequency of a speed detected signal obtained from a pulse generating means. CONSTITUTION:A signal obtained from the frequency generator of a cylinder motor 28 has a waveform (a) after it is amplified by an amplifier 17 and shaped in waveform by a waveform shaping circuit 18 and is inputted into a flip-flop 19. The output signal (b) of the flip-flop 19 is supplied to a monostable multivibrator 21 and inverting circuit 20 and becomes each output signal (d) and (c). The signals (d) and (c) become a signal (e) after passing through an AND gate circuit 23. The signal (e) is converted into a trapezoidal wave signal (f) at a trapezoidal wave generating circuit 24 and the sloping part of the trapezoidal wave is increased or decreased in accordance with the variation of the part A of the signal (e). Moreover, the signal (e) and (f) are supplied to an NOR gate circuit 22 and the part (B) of the trapezoidal wave (f) only is fetched and supplied to a sample holding circuit 25. The speed of the cylinder motor 28 is controlled by the output voltage of the circuit 25.