Automatic frequency control
The automatic frequency control refers to the control of the frequency of a generator or oscillator to a predetermined frequency. For this purpose, a control voltage is derived from the difference between the oscillator frequency and a reference frequency and added to an actuator.
A PLL circuit is usually used today to generate this control voltage . In radio technology, a capacitance diode on the oscillator's resonant circuit is used as an actuator .
The reference frequency is usually generated by a crystal oscillator or derived from it by means of a frequency divider or frequency multiplication in order to achieve a low drift and temperature dependence.
literature
- Helmut Röder, Heinz Ruckriegel, Heinz Häberle: Electronics 3rd part, communications electronics. 5th edition, Verlag Europa-Lehrmittel, Wuppertal, 1980, ISBN 3-8085-3225-4