| 摘要 |
PURPOSE:To increase the transfer speed of data by converting the waveform inputted from a cassette tape recorder to the waveform on the basis of the midpoint of said waveform and frequency-modulating the same through a demodulating circuit. CONSTITUTION:The reproduced output of a cassette tape recorder 1 is applied with peak holding by a peak holding circuit 3 and the midpoint of the reproduced waveform is obtained by a midpoint detecting circuit 4 by using these peak values. A comparator compares the magnitude between this midpoint and the reproduced output continuously, outputs the results thereof and inputs the same to a demodulator 2. Hence, the frequency-modulated data are accurately demodulated by the demodulator 2. This makes it possible to increase the modulating frequency or decrease the frequencies of the waveform constituting one bit. With such constitution, the transfer speed of the data is increased. |
