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 the SGS manual of linear integrated circuits of 1982. The CMRR depends on...
In the figure we have a receiver for frequency modulated light signals (see the transmitter in...
In the figure we have a high stability voltage reference, providing a voltage of 10 V at the...