AI signal quality for Poisson signal

[robertam]

I have a PXIe-6356 in a chassis that I'm using to sample electrons arriving at

a photomultiplier. The output from the photomultiplier is amplified and I'm

measuring it as a voltage using the analog input lines of the 6356. The

electron flux is < 1 nA, so generally too high to sample fast enough to

count individual electrons, but it is still has a lot of instantaneous Poisson noise.

Presently if I sample at say 100 kHZ, the AI trace is quite noisier than compared to

the output from another vendor's hardware. I searched through the API for

functions so I might control the sampling period and averaging behavoir but

I've come up empty. Is there any sample-and-hold functionality or similar for this device?

At present the only approach I can see to reduce the signal noise is to

sample at the max rate and then average in software post-acquisition.

Are there NI PXIe cards that can do >1 MHz integrated sampling with some duty

cycle control?

I'm currently using the Python wrapper for NIDAQmx, but I'm happy to use the

ANSI-C API if needed.

I also have a PXIe-7962R FPGA in the same chassis which is being used to collect

data from a fast CMOS camera. Is there a way to trigger tasks for the 6356

from when the 7962R starts acquisition? Currently we have an external trigger line

but that creates some clock slew. The X-series reference manual mentions the use

of the 'PXIe_CLK100' clock. There's one example:

https://github.com/ni/nidaqmx-python/blob/master/nidaqmx_examples/ai_multi_task_pxie_ref_clk.py

but it shows two DAQmx devices talking to eachother. Is there an C-API for the

7962R? I searched but I couldn't find an API or even a reference manual for

the device.

[Terry_ALE]

See http://www.ni.com/product-documentation/9036/en/

[Stephen_B]

As Terry_ALE mentioned, FlexRIO devices can be controlled with the FPGA Interface C API.

There is also a Python API for the FPGA Interface, see https://github.com/ni/nifpga-python for details.