This circuit was obtained from an 80's EDN. The components used are still common. The circuit can be used as a shield and the frequency is approximately 775 Hz.
For analog lines, this circuit was found in the August 1994 issue of Electronics Now magazine. The...
This low-noise hydrophone circuit was found in a 1980s Linear Technology component manual. The...
This circuit is from an Electronic Design of the 90's. The circuit can be implemented with more...