Patent ID: 9075696
Filing Date: 2015-07-07
Classification: G01R,G16Z

Abstract:
1. A method for isolating an interval of interest in a signal under test in a test and measurement device, the test and measurement device including trigger circuitry and an envelope detector circuit, the method comprising: receiving the signal under test at a terminal of the test and measurement device; the envelope detector circuit producing an envelope signal representing the duration of the envelope from the signal under test, the envelope detector circuit further detecting an edge transition within the signal under test, starting a timer to measure an inactivity time between the detected edge transition and a following adjacent edge transition, resetting the timer at the following adjacent edge transition, and setting an end of the envelope signal when the timer exceeds a predetermined amount; the trigger circuitry receiving the envelope signal from the envelope detector circuit; and the trigger circuitry isolating the interval of interest in the signal under test by using the envelope signal, the method further including: latching a first occurrence of an edge transition in the signal under test as a beginning of the envelope signal, wherein the edge transition is in a certain direction; responsive to the latched first occurrence of the edge transition, setting the envelope signal to HIGH; starting the timer upon each occurrence of an edge transition in an opposite direction; resetting the timer upon each occurrence of an edge transition in the certain direction; timing out the timer when the timer exceeds the predetermined amount prior to the resetting step; and responsive to the timer timing out, setting the envelope signal to LOW.