This circuit was obtained from an American 1980s documentation. The frequency depends on the crystal and the circuit may be a PNP that reaches the generated frequency.
This circuit was found in a 2003 documentation. Its purpose is to check if the transmitter of an...
Found in old English documentation this circuit evaluates the power of a transmitter. The circuit has...
The circuit shown is suggested by National Semiconductor's Linear Applications Handbook. The base...