| 摘要 |
PURPOSE:To allow a capacitor used for the filter to have a capacitance of one over the gain of the Miller integration amplifier so as to integrate a filter capacitor as an IC by using a Miller integration amplifier to constitute a low pass filter for DC feedback. CONSTITUTION:An output signal of a limiter amplifier 5 is inputted to a detector 6 and inputted to a Miller integration amplifier comprising TRs 23, 24, resistors 27, 28 and capacitors 25, 26 via resistors 21, 22. Let the gain of the Miller integration amplifier be A and the capacitance of the capacitor 25 be C, since it is equivalent in the Miller integration amplifier that a capacitance of (1+A)Co is incorporated between a base of the TR 23 and ground, the capacitor and the resistor 21 form a low pass filter. A signal smoothed by the low pass filter is inputted to a differential amplifier circuit comprising TRs 9, 10, a difference between collector currents of the TRs 9, 10 is fed back to an input section of the limiter amplifier to apply DC bias. |
