A precision frequency standard comparison method and instrument

The linear phase comparison method is used widely in the long-term performance measurement of frequency standards. Combined with a high-speed voltage measuring method, high-resolution short-term stability measurement can also be accomplished based on the phase comparison device. In this case, sampling speed, voltage measuring accuracy and the measuring range will influence the comparison precision of the frequency standard. For higher resolution and convenient use, a "voltage self-correction" method based on linear phase comparison can be used. In the frequency standard comparison, 1/spl times/10/sup -13///spl tau/ measurement precision can be obtained and it has a good identical measuring result with other high-precision frequency standard comparators.