This filter was found in Exar documentation from the 1980s. The circuit has an attenuation of 60 dB at the selected frequency. The power supply must be symmetrical.
The circuit in the figure uses the four current amplifiers of the LM3900 to generate a sawtooth signal...
The presented circuit was suggested by the 1994 Linear Applications Handbook from National...
This circuit was found in a Motorola documentation from 1968. The load current is 10 A. The...