Samples question

[swanthog]

Hello.

QQ, let's say I have a 62xx multifunction DAQ sampling at 1KHz and program it to return 200 samples. Which samples are returned? Are these downsampled from 1KHz (average filter)? The alternative would be for the DAQ to return every 200th sample but this doesn't make sense to me -- I would just sample at 200Hz and return 200 samples in this case.

Thank you.

[rizardus]

Every sample in 0.2 seconds.

The frequenzy is used to set the timespan between the samples, like 1/1kHz = 0.001s (T_a = 1/f). This means that every 0.001s a sample gets measured by the device. If you sample at 200Hz you would read every sample for 1 second.

I am not sure if I understand your question right but it seems to me that you didnt get the basics of digital signal processing quite right. If you need 200 samples and set the clock to 1kHz there is no need for downsampling.

[swanthog]

The question relates to the sampling rate and "samples" configuration settings that are required for acquisition. I was having trouble getting a clear answer on the reason for the "samples" cfg setting.  I framed the question a different way to try and better understand this.

Lacking a clear understanding, I set "samples" to whatever my sampling rate is. Example: sampling rate = 1KS/s, samples = 1KS.

If I set the sampling rate for 1KS/s, I expect to receive all of the sampled data. So, I wanted to understand the need for the samples cfg setting.

I suspect it is intended to save on space requirements much like downsampling. I have been looking for clarification on this for years.