Browse Prior Art Database

Pulse Duration Measurement

IP.com Disclosure Number: IPCOM000091892D
Original Publication Date: 1968-Jun-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 29K

Publishing Venue

IBM

Related People

McDowell, AW: AUTHOR

Abstract

This method for measuring the time duration of an unknown pulse width involves circulating the pulse repeatedly through a logic circuit and, on each cycle, subtracting some time value from the pulse, until the pulse becomes either extinguished or too narrow to continue cycling. The total number of cycles required are counted as a digital measure of the width of the original input pulse.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 67% of the total text.

Page 1 of 2

Pulse Duration Measurement

This method for measuring the time duration of an unknown pulse width involves circulating the pulse repeatedly through a logic circuit and, on each cycle, subtracting some time value from the pulse, until the pulse becomes either extinguished or too narrow to continue cycling. The total number of cycles required are counted as a digital measure of the width of the original input pulse.

An input pulse of unknown width Tu is applied to the logic network at Or 1. The Or output is applied simultaneously to delay circuits 2 and 3. Outputs from the delays are applied to And 4. The latter's output is connected back to Or 1 to provide the feedback path required for cyclic operation. In addition, And 4 is connected to binary counter 5.

In the timing waveforms, the input to Or 1 at point A is the unknown pulse of width Tu. Points B and C show that the pulse is delayed in time by T2 and T1 in circuits 2 and 3, respectively, and then applied to And 4. The latter provides signal D which is a pulse having a time period To equal to Tu - (T2 - T1), which is fed back to Or 1. The original input pulse to Or 1 has to end by this time so that Or 1 only sees one input at a time. Therefore, a constraint is that either T1 or T2 be greater than Tu.

Signal D causes counter 5 to increment by one as an indication that the original pulse width is at least equal to T2 - T1. The operation continues, incrementing counter 5 once for each cycle until the pulse width o...