A Quartz Servo Oscillator

The paper deals with a 5 mc oscillator whose frequency instabilities due to vacuum tube effects are at least 100 times less than those present in the best conventional oscillators which achieve stabilization by resonant vector balance. By using quartz crystals of low drift, it is therefore possible to reduce unpredictable frequency changes to one or two parts in 1010. The tubedependent instabilities in conventional oscillators are reviewed, the conclusion being that even with circuit Q values as high as 2 million it is not possible to guarantee frequency instabilities as low as 10-9, much less 10-10. A plan for dual stabilization by resonant-loop balance and bridgeoperated servo to one part in 1010 is described. The development of an oscillator based on this plan and intended as a working frequency standard is explained with the aid of block diagrams and performance data.