Stabilised frequency generator with high precision and stability - by keeping control range of one oscillator clear of adjacent harmonics

摘要

The stabilised frequency generator has the outputs of two oscillators mixed. The first oscillator is tuned by a varactor diode from a crystal circuit. The second oscillator (2) also contains a quartz crystal (13) to hold its frequency at a given value but allowing it to be pulled slightly each side of this value by a control circuit (15-17). The spacing between adjacent harmonics of the basic crystal frequency for the first oscillator is chosen small enough not to exceed the control range of the given frequency. The advantage lies in high precision and stability with few components.