There is a data acquisition board recording analog signals from 10 channels with multiplexing. If one wants to sample each channel with for example 2000Hz and the number channels is 5 should the sampling frequency be set to 5x2000=10000 for the board? I have a confusion with the skew and sampling. here is the device specs I'm talking about: http://www.mccdaq.com/usb-data-acquisition/USB-1616HS-BNC.aspx

  • \$\begingroup\$ Probably not, but I've seen it both ways. The docs should absolutely clarify, as should sampling a sine wave on two channels and making sure your sample rate isn't off by a power of 2. \$\endgroup\$ – Scott Seidman Oct 17 '13 at 21:28
  • \$\begingroup\$ here is the device specs: mccdaq.com/usb-data-acquisition/USB-1616HS-BNC.aspx \$\endgroup\$ – user16307 Oct 17 '13 at 21:34
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    \$\begingroup\$ Can't help-- I won't register to download the user manual, but guaranteed it's in there. \$\endgroup\$ – Scott Seidman Oct 17 '13 at 21:39
  • \$\begingroup\$ whats in there? if u wanna know its a typical daq system there is a multiplexer which multiplexes one by one each channel and sends the data to adc. isnt it enough to answer my question???? \$\endgroup\$ – user16307 Oct 17 '13 at 21:46
  • \$\begingroup\$ @user16307 "it" is the answer to your question. You're asking about how the software or SDK communicates with the devices. Usually, any box that you type in that says "sample rate" or library call with a sample rate argument refers to samples per second for each channel. Since we're talking about software here, only the documentation can tell you for sure. The 1MS/sec maximum rate spec, by the way, may well be for one channel. \$\endgroup\$ – Scott Seidman Oct 17 '13 at 22:15

If you want to capture a sinewave of 2kHz then sample as fast as you are able and at the very least you'll need to sample at 5kHz (to avoid unwielding brick-wall filtering on the front end of your ADC).

If you don't sample at a high enough rate you'll get aliasing so, try and sample as fast as you can - that's one channel. Aliasing: -

enter image description here

For ten channels feeding the ADC via a multiplexer then you need to sample ten times as fast as you were for one channel.


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