Measuring SNR, SINAD,and THD Quickly

摘要

Precision sine wave measurements are a challenge when they exceed the capability of the digitizer, but the performance can be improved with a notch filter or nulling circuit. Though simple, the notch filter requires calibration, is limited to one frequency, and can be difficult to build and maintain. The AC nulling approach used in the Data Converter Test Module achieves high-precision performance at any frequency at the fastest possible measurement speeds without additional load board circuitry.