摘要 |
<p>A method and apparatus for measuring very short time periods, or differences between two events, such as the delta-T between a trigger point on a waveform and a sampling clock edge of a digital oscilloscope. The delta-T measurements are made using the time-to-voltage transformation of an integrator. The output sweep ramp of the integrator is normalized to a fixed differential time and differential amplitude by correction current provided by a reference circuit that has a reference integrator substantially identical to the delta-T integrator. The reference integrator is operated at the same timing as the delta-T integrator, and an error correction loop furnishes the right amount of current to both integrators to normalize the peak voltage of both to a predetermined reference voltage. <IMAGE></p> |