| 摘要 |
PURPOSE:To prevent the lowering in the output voltage caused with high recording density, by the constitution that the increase characteristics of output voltage due to increase in the frequency of a differentiation device can be used. CONSTITUTION:Fine reproducing analog signals (a), (a') different from 180 deg. by phase read in at the magnetic head 7 are of equal amplitude and the output voltage is increased with the differential amplifier 8 amplifying the voltage of opposite phase only to obtain the output of (b), (b'). Further, the phase of this output is changed at the differentiation device 9 to obtain the differentiating signals (c), (c'). Since the phase of the signals (c), (c') is different by 90 deg. from that of the signals (b), (b'), the peak point of the reproducing analog signals (b), (b') is in coincidence with the zero level point of the signals (c), (c'). Further, the differentiating device 9 prevents the lowering in the output when the magnetic recording density is increased and the frequency is greater, to obtain a given output voltage. Thus, with the constitution like this, the lowering in the output voltage caused with higher recording density can be prevented. |
