Found in Exar documentation from the 1980s, this circuit has a 60 dB cutoff at 1800 Hz. The circuit can be adapted to operate at other frequencies.
The maximum frequency of the oscillator shown in the figure is around 3 MHz. The trimmer adjusts the...
This circuit was obtained in a 1977 Radio Handbook. The transistor is from the era and the coils...
August 2017 - STMicroelectronics' BlueCoin development environment is available at Mouser...