| 摘要 |
PURPOSE:To demodulate a PE signal into an NRZ signal by a simple circuit by outputting a waveform which falls with a prescribed time constant by detecting the change point of the waveform of a readout signal, and inverting the state of the output waveform corresponding to the fall of the output waveform. CONSTITUTION:An analog PE signal inputted to an input terminal 1 is converted into a digital PE signal (a) through an AD converting circuit 2, and the signal is inputted to rise and fall differentiating circuits 3 and 4, which output rising and falling clock pulses (b) and (e) respectively. Consequently, the trigger clock (d) of a waveform shaping circuit 7 appears at the output of an OR gate 6. The waveform shaping circuit 7 is triggered by a trigger clock (d) to output logic[1]and, when the trigger clock (d) is not received during the period a prescribed time constant, inverts the output to logic[0]. For this purpose, the output waveform (e) of the circuit 7 is passed through the 2nd fall differentiating circuit 8, etc., to obtain demodulated data (f). The data (f) is in NRZ form. Thus, the PE signal is converted into the NRZ signal by the simple circuit. |
