FSK DATA REPRODUCING DEVICE

摘要

PURPOSE:To attain the reproduction of FSK data having excellent temperature characteristics with simple constitution by obtaining a reference voltage of a comparator shaping waveform of an FSK demodulation signal from an output signal of an FSK demodulation section. CONSTITUTION:An output terminal 3 of the FSK demodulation section 1 is divided into two; one is connected to an input terminal 5 of the 1st comparator 2 to shape a data waveform of FSK and the other is connected to a peak hold circuit 8. The circuit 8 holds the peak of the output signal of the demodulator 1 by using a diode 10 and a capacitor 11, its output is adjusted in terms of the level by using a transistor 12 and a variable resistor 13 of an emitter follower and the result is given to an input terminal 4 as a reference voltage of the comparator 2. Since the reference voltage of the comparator 2 is also fluctuated even if the level of the output of the demodulation section 1 is fluctuated because of temperature change, the output waveform from a terminal 7 is a stable signal to temperature. Moreover, a signal is inputted to the 2nd comparator 18 from a terminal 14 of the demodulation section 1 and a logic signal level to an input having a prescribed level or over is outputted by comparing the signal with a fixed reference voltage 16.