This circuit operates from 20 Hz to over 20 kHz and is easily tunable. We found it in a 70s documentation. The circuit can be implemented with modern operational amplifiers.
In the figure we show the typical configuration of a shared line using a twisted pair where the...
We found this digital CMOS circuit in a documentation from the 90s. The circuit generates signals...
This tuning-free circuit was found in an old operating amplifier manual. The setting can serve as...