This circuit was found in a British documentation from 1969. It can be implemented with modern transistors. The pass band is 6 MHz.
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...