what is the min pulse width that can be measured using a 32-bit conter?

[Share_Good]

what is the min pulse width that can be measured using a 32-bit conter?

and also by chnaging the referenced Clock, can we measure as min as 10ns pulse width?

[AnalogKid2DigitalMan]

It primarily depends on the clock rate, not the number of bits in the counter.

What hardware did you have in mind, if any, look up the specs in the online manuals under the Support Tab.

[Share_Good]

if i use an on board 80MHz clock of PCI-6602 Counters/Timers card, i understand that the min pulse width possible to be measured is 12.5nSec.

If i want to measure a 40nSec pulse width, is it possible with the same and how accurate that can be....?

[stilly32]

You could measure a 40ns pulse, but not with a great degree of accuracy. Here's a good document on how counter pulse width measurements are handled:

http://zone.ni.com/devzone/conceptd.nsf/webmain/7C77FB9EDC17C3C386256802007B8AB3

With a 40 ns pulse, you'd have 3 counts per pulse so your uncertainty is pretty high (33%). Another way to look at it would be that you would read either 3 counts or 4 counts which would be values of 37.5ns (3*12.5ns) or 50ns depending on where the rising edges fall. So you wouldn't be able to tell the difference between a 40ns pulse and a 42ns pulse, but you would between a 40ns and a 100ns.

Hope this helps,

Andrew S

National Instruments

Message Edited by stilly32 on 09-18-2006 05:04 PM

[Moschdschlotzer]

Hallo,

ich habe ein ähnliches Problem und ziemlich wenig Ahnung davon...

Also Hardware:

Rechner: NI PXI-1042Q

Karte: NI PXI-6221

Ich lese damit 2 Signale von 2 Heidenhain Drehgebern mit 18000 Strichen pro Umdrehung und

messe mit den Countern jeweils die Periodendauern. Die Kabel sind jeweils angeschlossen an CTR 1 bzw. CTR 2 Gate.

Bei 50 Umdr./s habe ich eine Periodendauer von ca. 6E-6.

Nun meine Frage:

Woher bekommt die Karte die Taktrate des Zählers. Hat die Karte selbst einen Taktgeber? oder muß ich an CTR 0 bzw. CTR 1 Source

etwas anschließen? Mit welcher Taktung taktet die Karte?

Bitte helfen Sie mir möglichst schnell!!!!

Gruß

Jens Bihr

[stilly32]

Hi Jens,

Can you post this back in English? I would rather not risk mistranslating this (Google or otherwise) and giving you incorrect information. It might also be easier to contact your local NI branch for support.

Thanks,

Andrew S.

National Instruments