| 摘要 |
PURPOSE:To avoid malfunction by varying a reference signal inputted to a comparator the same as a fluctuation of a DC component of a signal waveform so as to apply accurate waveform shaping even if the DC component in the signal is timewise fluctuated. CONSTITUTION:A signal current source 2 is subject to current voltage conversion by a resistor 3, and the result is given to a common base of an NPN transistor(TR) 8 and a PNP TR 9. Let a voltage of a base common connecting point 4 be VA, a voltage across capacitor be VB and base-emitter voltage when the TRs 8,9 are active be respectively VBE, N and VBE, P. In case of the voltage VA expressed in a relation of VB-VBE,P<VA<VB+VBE,N, the TRs 8, 9 are interrupted and the voltage VB shows a constant value. In case of VA>=VB+ VBE,N, the TR 8 is conductive and the TR 9 is interrupted, then the relation of VB=VA-VBE,N exists as the voltage VA rises. In case of VA<=VB-VBE,P, the TR 8 is interrupted and the TR 9 is conductive, the VB is expressed as VB=VA-VBE,P as the voltage VA drops. The voltages VA, VB are compared by a comparator 5 to obtain an output waveform subject to waveform shaping. |
