how to cope with sytem noise of DAQ?

[fenny]

I found that my system noise is too much for my data acquisition.

the frequency range of the noise is so wide and the magnitude is comparable to my useful data.

Waht can I do to acquire my data?

[chrisger]

hi there

if the signal changes quite slow compared to the noise you could try to use a median filter.

[IanW]

Take a look at the following link

http://zone.ni.com/devzone/conceptd.nsf/webmain/01F147E156A1BE15862568650057DF15

it may give you some ideas.

Ian

[AnalogKid2DigitalMan]

What is the noise amplitude, sampling rate, the environment in terms of electrical devices and EMI/RFI, and any means you have implemented to reduce noise (shielding, grounding, cable lenghts and routing, etc). Trying to get some clues to assist. You can always take multiple acquisitions and average the data to effectively remove some effects of noise.

Do you have an oscilloscope to verify presence and nature of noise?

[fenny]

what cable can cause noise, the data cable ?power cable? I do have long power cable.

[AnalogKid2DigitalMan]

Power cables are usually a source of noise if carrying AC or high-frequency signals with fast rise/fall times. Signal cabling should be kept away from such power lines. If they have to cross, do so at right angles to each other to minimize cross-coupling. Proper shielding and grounding is always in order.