Checking the frequency of highly stable generators

Conclusions

• 1. The proposed method permits the comparison of the frequencies of generators having an identical nominal value and a submultiple ratio of nominal values of frequency.

• 2. Since the circuits shown do not contain resonant or phase-splitting circuits tuned to a specific frequency, they can be used over a wide frequency range without readjustment.

• 3. Use of a limiter at the input of the signal zero-crossing detector and a comparison circuit using tunnel diodes has afforded a dynamic range of amplitudes of input signals from 0.5 to 20 V, which is especially convenient in the comparison of the frequency of a test generator having a frequency obtained from radio receivers not having automatic gain control.

• 4. The errors in comparing frequencies by means of a flip-flop as the phase detector and with the aid of a recording of the oscillations of the difference frequency on the stripchart of a recording instrument are approximately the same as for the oscillographic method of comparing frequencies by means of a circular sweep with a modulating spot that is 1/100 the length of the periphery.

• 5. Recording of the indications on a stripchart eliminates continuous participation of an operator in counting the number of oscillations, which is convenient during long-term or round-the-clock comparison of the frequencies of generators.

• 6. Stencils and recording instruments the pointers of which move perpendicularly to the longitudinal axis of the stripchart over the entire width permit a rapid orientational evaluation of the difference frequencies from the recording being made.