Time measurement in automatic test equipment
AssigneeTeradyne, Inc.
InventorsWilliam J. Bowhers, Michael R. Ferland
Life of this patent
Estimating the term…
Abstract
Apparatus for automatically testing electronic circuits and performing time measurements, including a time measuring circuit for counting clock pulses provided between stop and start event edges presented to it, two independent input selectors for each selectively connecting one of a plurality of its inputs to the time measuring circuit, and a plurality of local comparators located within the test apparatus near sources of signals to be timed and generating an event edge upon receiving a signal crossing a threshold value. Also disclosed are making time measurements of signals at digital and analog pins using local comparators connected to input selectors over deskewed transmission paths and connecting a local comparator to the filter output of an analog instrument.
Claims21
Apparatus for automatically testing electronic circuits and performing time measurements, said apparatus comprising
- a fixture including node contacts contacting nodes of a circuit under test,
- means for generating input test signals and providing them to said node contacts,
- means for detecting and processing output signals from said node contacts,
- a clock providing clock pulses,
- a time measuring circuit for counting clock pulses provided between two event edges presented to it,
- two independent input selectors each for selectively connecting one of a plurality of its inputs to said time measuring circuit and to transmit event edges provided at said inputs to said time measuring circuit,
- said time measuring circuit being able to use an event edge from either said independent selector as a start event edge or a stop event edge,
- a plurality of local timing comparators located within said test apparatus near sources of signals to be timed and generating one of said event edges when a said signal to be timed crosses a threshold value, said signals to be timed appearing at said node contacts, said comparators having thresholds that are programmable to adjust them to the event of the particular signal to be timed,
- transmission paths connecting said local timing comparators to respective said selector inputs,
- first and second said local comparators being connected to one said independent input selector, and a third said comparator being connected to the other said independent input selector, said first, second, and third local comparators being dedicated solely to measuring time.
Apparatus for automatically testing electronic circuits and performing time measurements, said apparatus comprising
- a fixture including node contacts contacting nodes of a circuit under test,
- means for generating input test signals and providing them to said node contacts,
- means for detecting and processing output signals from said node contacts,
- a clock providing clock pulses,
- a time measuring circuit for counting clock pulses provided between two event edges presented to it,
- two independent input selectors each for selectively connecting one of its inputs to said time measuring circuit and to transmit event edges provided at said inputs to said time measuring circuit,
- said time measuring circuit being able to use event edge from either said independent selector as a start event edge or a stop event edge,
- a plurality of local comparators located within said test apparatus near sources of signals to be timed and generating one of said event edges when a said signal to be timed from a source crosses a threshold value, said signals being timed appearing at said node contacts,
- some said comparators being timing comparators dedicated solely to measuring time of signals at noes and some being digital comparators used to both detect digital output signals and to measure time,
- transmission paths connecting said local comparators to respective said input selector inputs, and
- means to deskew transmission paths from timing comparators and digital comparators, so that events at digital data nodes and other nodes can be timed in the same time measurement.
Apparatus for automatically testing electronic circuits and performing time measurements, said apparatus comprising
- a fixture including node contacts contacting nodes of a circuit under test,
- means for generating input test signals and providing them to said node contacts,
- means for detecting and processing output signals from said node contacts,
- a clock providing clock pulses,
- a time measuring circuit for counting clock pulses provided between two event edges presented to it,
- a first alternating current measurement instrument including a first filter connected to receive an analog output signal from a said node contact of a circuit under test and a first analog to digital converter connected to receive the output of said first filter,
- a first local timing comparator connected to said first filter to receive a filtered analog output signal and generate said event edge when the filtered signal crosses a threshold value, and
- a first transmission path connecting said first local timing comparator to said time measuring circuit to transmit said event edge to said time measuring circuit.
Dependencies are inferred from the claim text.