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Propagation Delay and Pulse Width Tester

IP.com Disclosure Number: IPCOM000091770D
Original Publication Date: 1968-May-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 3 page(s) / 62K

Publishing Venue

IBM

Related People

Millham, EH: AUTHOR [+2]

Abstract

A method of measuring propagation delay and pulse width is provided by this circuit arrangement. Its output is a measurable DC voltage which can be monitored by a computer system. Input terminals 1...N are each connectible to the test points of circuits in which input pulses are to be measured for either propagation delay or width. Each input terminal connects to a respective discriminator 2 that provides an output signal each time the input voltage level passes through a preset reference level. Output signals from discriminators 2 are supplied to Start Or 3 and respective And's 4. A conditioning input to each And 4 is provided by the control voltage level on a Stop Select line for each corresponding input terminal. Signals from And's 4 pass through Stop Or 5 and Delay 6.

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Propagation Delay and Pulse Width Tester

A method of measuring propagation delay and pulse width is provided by this circuit arrangement. Its output is a measurable DC voltage which can be monitored by a computer system. Input terminals 1...N are each connectible to the test points of circuits in which input pulses are to be measured for either propagation delay or width. Each input terminal connects to a respective discriminator 2 that provides an output signal each time the input voltage level passes through a preset reference level. Output signals from discriminators 2 are supplied to Start Or 3 and respective And's 4. A conditioning input to each And 4 is provided by the control voltage level on a Stop Select line for each corresponding input terminal. Signals from And's 4 pass through Stop Or 5 and Delay 6.

Signals from Or's 3 and 5 are gated through respective And's 7 and 8 which are conditioned by a Pulse Width Select line and Inverter 14 according to whether delay or width measurements are to be obtained. Signals from And's 7 or 8 are supplied through Or 9 and And 10, preconditioned by the present trigger state, to turn on trigger 11. When the latter is turned on, linear ramp Voltage Generator 12 is started. Trigger 11 is turned off by a subsequent signal from Or 5 through And 13 which is preconditioned by the state of trigger 11. The test circuit is reset by a selective signal on line 15 to both trigger 11 and Generator 12.

When measuring pulse propagation delay, two input terminals, such as 1 and N, are connected to the two test points of the circuit for which the delay is to be found. One Stop Select terminal, for example N, is at its upper conditioning level, and the Pulse Width Select line is at its lower level, blocking And 8 and conditioning And 7. Assume that the test pulse occurs at input 1 before appearing at input N. When the pulse at input 1 passes through the reference level, discriminator 2 for that input produces a signal of short duration which operates through conditioned And 7,, Or 9, and And 10 to turn on trigger 11. The change in trigger state starts Generator 12, blocks And 10, and conditions...