Testing Oscillators by Waveform Comparison with the Ideal Sine-Wave

摘要

In context of the oscillation-based-test (OBT) technique, a simple and low-cost method of testing oscillators by comparison of finite segment of waveform with the ideal sine-wave is presented. The method is based on the subtraction of two sigma-delta modulated signals with the aid of a 1-bit subtractor that employs oversampling based noise-shaping. An up/down counter extracts the average of the bit stream that is used as a fault signature. The simulation results on the example of the Van der Pol oscillator show that the proposed fault signature is sensitive to the frequency and amplitude deviations and is able to detect non-linear oscillation as well.