| 摘要 |
PURPOSE:To obtain a stable demodulation signal not affected by temperature fluctuation by adding a demodulation voltage and a DC current obtained respectively from an inverting output and a noninverting output of a monostable multivibrator circuit. CONSTITUTION:An addition amplifier circuit 6 adding outputs of 1st and 2nd low pass filters 4, 5 is provided. That is, a voltage applied to the addition amplifier circuit 6 is coincident with a center voltage of a demodulation voltage being an output of the 1st low pass filter 4 and with a DC voltage being the output of the 2nd low pass filter 5 and the fluctuation with respect to the temperature change is opposite to each other, then the fluctuation is cancelled by adding the both thereby obtaining the demodulation voltage having an always constant center voltage. Thus, after the demodulation voltage is subject to offset adjustment to a proper value depending on an output offset voltage of an offset voltage source 7, the result is inputted to a comparator circuit 8 and the demodulation signal is obtained by comparing it with a reference voltage VREF to obtain the demodulation signal, resulting in obtaining the best bit error rate. |
