Frequency stabilized microwave signal source
AssigneeGTE Automatic Electric Laboratories Incorporated
InventorVolker B. Weise
Life of this patent
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Abstract
The frequency of a microwave oscillator is stabilized by coupling a portion of the RF signal therefrom to an HF oscillator operating at a sub-multiple of the microwave frequency and producing a strong harmonic at the microwave frequency in order to cause the operation of the microwave and HF oscillators to be locked together. The HF signal frequency, which includes any drift in the microwave oscillator frequency, is divided down a specified amount and compared with the frequency of a stable crystal reference oscillator in a comparator. The output of the comparator is a DC error voltage which is proportional to any drift in the frequency of the microwave oscillator. This error voltage is applied to the microwave oscillator to cause the operating frequency thereof to be more nearly constant.
Claims10
A stabilized microwave signal source comprising:
- a first oscillator which is a microwave oscillator for operating at a radio frequency (RF) f.sub.o which may have a frequency drift .DELTA.f therefrom;
- a second oscillator which is a stable crystal oscillator producing a reference signal having a stable low frequency reference frequency f.sub.R ;
- a third oscillator for operating at a frequency f.sub.S which is a sub-multiple of the microwave frequency f.sub.o, said third oscillator producing a harmonic signal at the RF frequency f.sub.o, the frequency f.sub.S being less than the microwave frequency f.sub.o ;
- first means for coupling a portion of the RF signal from said first oscillator to said third oscillator for causing the operation of these oscillators to be locked together such that the operating frequency of said third oscillator remains the same sub-multiple of the operating frequency of said first oscillator and follows any frequency drift .DELTA.f in the latter;
- second means for dividing the frequency f.sub.S of a signal down to the frequency f.sub.R ;
- third means coupling the output signal of said third oscillator to said second/dividing means;
- fourth means for comparing the frequency of the divided down signal from said second means with the stable reference frequency f.sub.R for producing a DC control voltage that is proportional to the difference therebetween;
- and
- fifth means coupling the control voltage to said first oscillator for causing the operating frequency thereof to remain more nearly equal to the frequency f.sub.o to compensate for frequency drift .DELTA.f in said first oscillator.
Dependencies are inferred from the claim text.