A method of stabilizing the frequency of a radio transmitter by means of an automatic monitor

The paper describes a means of automatically stabilizing the frequency of a simple self-oscillatory system such as is used in small radio transmitters. The frequency is controlled by a master oscillator of small power and a monitoring condenser which automatically corrects the frequency variations due to changes in circuit parameters. The degree of stabilization which can be obtained is dependent upon the rate of variation of the circuit parameters, being of the order of 10 parts in 1 million for slow changes and 30 parts in 1 million for changes at a rate of 25 times a second. Means of eliminating ¿key chirps¿ in the received signal are also discussed.