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PC controlled peak-sensing ADC's
kdc
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04-11-2002 04:40 PM
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Is anyone aware of a peak-sensing ADC (as is commonly used in physics research, like an Ortec AD811) implemented on a PCI card? I need to measure the amplitude of a 300nsec wide photodiode pulse from a 1kHz rep rate laser. All I need is to monitor that amplitude with time, not characterize the exact pulse shape. I'd like to do this in Labview, but don't want to set up a fullblown CAMAC crate and controller.
Filipe A.
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04-12-2002 10:43 AM
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Hello;
As the frequency of that pulse is 333KHz, you need a DAQ board that can support that speed.
Also, since you don't need to characterize the pulse shape, the DAQ board that can go up to 500KHz would be enough for your application; such as the PCI-MIO-16E-4.
To implement that in Labview, you can use one of the DAQ Labview shipping examples, such as the Continuouos Acquisition and Chart (buffered).vi.
Hope this helps.
Filipe
As the frequency of that pulse is 333KHz, you need a DAQ board that can support that speed.
Also, since you don't need to characterize the pulse shape, the DAQ board that can go up to 500KHz would be enough for your application; such as the PCI-MIO-16E-4.
To implement that in Labview, you can use one of the DAQ Labview shipping examples, such as the Continuouos Acquisition and Chart (buffered).vi.
Hope this helps.
Filipe
PdB
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04-12-2002 02:59 PM
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Sorry, but according to my calculator a 300nsec pulse has a basic frequency of 3,33MHz. To measure this, you need at least 6,66MHz sample frequency (in practice a lot higher).
Can't you ask a kind electronics engineer to design a peak-detector circuit and connect it's output to a daq-board running at a moderate sampling-frequency.
Just a thought.
Can't you ask a kind electronics engineer to design a peak-detector circuit and connect it's output to a daq-board running at a moderate sampling-frequency.
Just a thought.
04-12-2002 03:45 PM
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Your calculator is correct! There is no way that I'm going to use a board that can sample fast enough to capture this fast pulse. That's my point. And sure, there are various hardware options, I'm just trying to not reinvent the wheel. If I use a peak detector circuit, it has to be reset. I'm trying to avoid having to synch the PC to the 1kHz rep rate of the laser.
PdB
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04-16-2002 02:36 AM
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The power of electronics is that sometimes manual (or programmed) support is not needed (the peak-reset).
From the short glance I took at the specs of the AD811 it seems a sample-hold system, triggered by the 1kHz It is possible to design a 1-channel circuit for your needs.
I asked my collegue electronics designer and the conclusion is that even a stand-alone design (with serial data output) is possible, so you could even save a DAC-board (guess NI would not like this).
If you are interested you can mail me at info@serenity.nl.
From the short glance I took at the specs of the AD811 it seems a sample-hold system, triggered by the 1kHz It is possible to design a 1-channel circuit for your needs.
I asked my collegue electronics designer and the conclusion is that even a stand-alone design (with serial data output) is possible, so you could even save a DAC-board (guess NI would not like this).
If you are interested you can mail me at info@serenity.nl.
