Filter circuit feeds bias voltage to operational transconductance amplifier input and connects selected capacitor to operational transconductance amplifier output to set corner frequency

摘要

The filter circuit has a filter contg. an operational transconductance amplifier (11,12) and an automatic corner frequency setting unit (200), whereby a bias voltage output parameter of the automatic setting unit is fed into a bias voltage connection of the operational transconductance amplifier and a capacitor is selected from a number of different capacitors (C11...C2m) as the capacitor for connection to the operational transconductance amplifier output to change the frequency setting range of the automatic setting unit.