We found this circuit in a 1977 factory documentation. The operational amplifiers can be 741 and the symmetrical power supply. Capacitors can be changed for operation at other frequencies.
This circuit is from Motorola documentation from the 70s. The transistors used are high voltage types...
This detector with ultra-low deviation was found in an American documentation from the 90s....
This model circuit was found in Radio Electronics magazine from February 1960. The power...