| 摘要 |
PURPOSE:To improve the recording density, by recording signals so as to decrease a reproducing level of a frequency component equal to a reciprocal of the minimum inverted interval in a digital signal in comparison with that of the frequency component equal to the reciprocal of the maximum inverted interval of the digital signal, in the titled signal recording and recording/reproducing system. CONSTITUTION:A digital data obtained by pulse-code-modulating an analog information signal is applied to an input terminal 9 and a clock pulse (b) having a period equal to a minimum inverted interval (bit period) of a data (a) is applied to another input terminal 10. In such a digital FM modulator 16, pulses c, d are generated at monostable multivibrators 11, 12, a pulse train (e) is obtained at an AND circuit 13 and an OR circuit 14, and a pulse (f) is generated at an flip-flop 15. The pulse (f) is inverted in a frequency 2F being a half time interval the bit period when the data (a) is logical ''1'' level and inverted in a frequency F being equal to the bit period when logical ''0''. The frequency components F, 2F are recorded at the same level depending on the characteristics where high frequency components are attenuated with the magnetic recording and reproduction, and the frequency 2F is taken as a frequency reproduced only at a low level at the reproduction. |
