We found this circuit in the National Semiconductor's Linear Applications Handbook of 1994. The circuit uses an operational transconductance amplifier.
The circuit suggested by National Semiconductor mows signals from a peak determined by the...
This 90's project shows how to use an old cassette recorder to practice telegraphy. In position A of the...
This circuit from Radio Electronics magazine, March 1994 edition uses two LM388 bridged, providing a 4...