Full Digital Phase Noise Measurement System based on Under Sampling Technique

This paper describes phase noise floor level of digital phase noise measurement. It has estimated the noise floor level of phase noise from ENOB of the analog to digital converter and sampling frequency. We have discussed phase noise measurement using normal sampling based on sampling theorem and under sampling which samples longer sampling period than the signal under the test. We compared the phase noise spectral density of noise floor between normal sampling and under sampling. As a result, measurement results are in good agreement in both methods.