This circuit was found in an 80's Electronic Engineering. The circuit uses operatives of the time that are not common today. The power supply must be symmetrical.
This circuit is more elaborate than the previous one, employing an integrated amplifier circuit of the...
This circuit is from a 2005 Linear Technology application manual. The circuit uses a commercial...
Found in an American paper from the 90's, this circuit can be adjusted to pass frequencies above 30 to 300...