| 摘要 |
PURPOSE:To eliminate the effect of speed fluctuation of a recording medium by an electric signal processing by applying pre-emphasis and de-emphasis to a high frequency component, superimposing a reference signal on an information signal at recording and obtaining a correction signal from the reference signal at reproduction in response to the speed fluctuation of the recording medium. CONSTITUTION:An information signal (a) is inputted to a pre-emphasis circuit 1, a harmonic is emphasized, a reference signal (c) and a waveform (b) are superimposed by a synthesizer 2, the result is amplified and recorded on a recording medium such as a magnetic tape by a head 6. The signal picked up by the head 6 is amplified by a reproducing amplifier 12 at the reproduction, demodulated by an FM demodulator 11 to obtain a reproducing signal (e). The signal (e) becomes a waveform (f) from which the reference signal is eliminated through a low pass filter 10, the high frequency component is compressed by a de-emphasis circuit 9 to form a waveform (g). The reproducing signal (e) is inputted also to a high pass filter 13, at which the waveform (h) corresponding to the reference signal (c) is extracted to obtain a correction signal (i). The level of the waveform (g) is corrected at a correction circuit 8 by using the correction signal (i) to suppress the level fluctuation.
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