Patent ID: 8872523

Claim:
Automatic test equipment for testing a circuit having an oscillating crystal, the automatic test equipment comprising: a generator for generating a first signal comprising an oscillating part having a plurality of predetermined frequencies, a first terminal for coupling the first signal to the oscillating crystal, wherein the plurality of predetermined frequencies are located inside a predetermined window around one of the resonance frequencies of the oscillating crystal, wherein each of the plurality of predetermined frequencies substantially equals one of the resonance frequencies of the oscillating crystal. wherein the first signal comprises a plurality of predetermined frequencies corresponding to resonance frequencies of the oscillating crystal; an analyzer, comprising a second terminal that is coupled to the oscillating crystal for detecting a second signal and a rectifier that is coupled in series with a low-pass filter for rectifying and filtering the second signal, wherein the width of the window is a full width at half maximum of a resonance curve of the oscillating crystal at one of the resonance frequencies; and a detector for detecting a DC-signal at the output of the low-pass filter and for signaling a valid test result for the oscillating crystal if the DC-signal exceeds a certain threshold value.