1047_1 - PhidgetEncoder HighSpeed 4-Input

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jaromrax
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1047_1 - PhidgetEncoder HighSpeed 4-Input

Postby jaromrax » Tue Sep 18, 2012 9:01 am

Hi,
I have an important (for me) question. Could this 1047_1 - PhidgetEncoder (or the other) used to count short pulses with random statistics? I speak about rates up to 10kHz, but the trick is that poisson statistical distribution can make it more complicated, so MHz resolution rate is important. Pulse width can be in general 0.1 us, NIM signal would be better than TTL in this case...
best regards
jaromir

fraser
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Re: 1047_1 - PhidgetEncoder HighSpeed 4-Input

Postby fraser » Tue Sep 18, 2012 9:37 am

what precisely do you mean when you say "short pulses with random statistics"? With emphasis on random statistics.

fraser
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Re: 1047_1 - PhidgetEncoder HighSpeed 4-Input

Postby fraser » Tue Sep 18, 2012 10:53 am

In general, the capacitance on the input line of the 1047_1 would degrade a 0.1us pulse enough that it would likely not trigger a count. Also, given a constant flow of 0.1us pulses, the counter in the FPGA would overflow, the input rate would have to average to less than a MHz over a given amount of time

jaromrax
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Re: 1047_1 - PhidgetEncoder HighSpeed 4-Input

Postby jaromrax » Wed Sep 19, 2012 6:49 am

I see. Concerning the statistics - I had in mind a radioactive decay. Usually, the pro devices have 25-100MHz countrate.
For my purpose, the pulse width can be a problem. I have 0.5us TTL. If 1047_1 could permanently register from 10Hz to 10kHz +- fluctuations down to zero, that would be already possible.
jaromir

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Patrick
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Re: 1047_1 - PhidgetEncoder HighSpeed 4-Input

Postby Patrick » Mon Sep 24, 2012 11:23 am

It sounds like you may want 1054_0 - PhidgetFrequencyCounter rather then 1047_1. The 1054 can work with much higher frequencies and is designed for counting. Are you working with a quadrature signal - which is what 1047 requires?

-Patrick


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