noise

[Aurore]

What can i do to delete noise on signal waveform 2Hz?
 i've put isolated wire and all frames  to earth ground.

i can't do low pass filter.

can you help me?

[Mathieu_R.]

Hi Aurore,

Which device do you use? What is the origin of the measured signal? What is the amplitude of the signal? Of the noise? When you say that you can't do a low-pass filter, are you talking about an analog filter placed between your source of the signal and your acquisition card, or a programmed filter ? (in LabVIEW for example)

Regards,

[Aurore]

Hello,

I use  a computer with a DAQboard 2000 card      
http://www.sm2i.com/viewproduct.php?CategoryID=4&ProductID=1014 ;
http://www.iotech.com/catalog/cat_pdf/DaqBoard_2000.pdf#search=%22daqboard%202000%22


This card dispatch a signal that i choose : a wave form to 2Hz and  1.0 Vpp   (i simulate heave sea)
The amplitude of noise is attached file : 10-15mV;

When i say that i can't use low-pass filter it's because my boss would like that i find the origin of noise. and after, if i don't delete noise i could use a low pass filter at the output of the  DAQboard 2000 card.

But i don't know how can i do.
I think that the supply of my computer give a no stabilize voltage and the DAQboard 2000 amplified that and give a noise signal.

do you have an idea?

Best regards,


Aurore de Gouvenain
Acri in

[Mathieu_R.]

Hi Aurore,

Your card may be sensitive to perturbations created by your computer power supply. But, I don't know this board, I never used it... I can't affirm that it's the source of your problem. DAQboard is not a National Instrument product. You should contact IOtech and their technical support: http://www.iotech.com/kb/search_ext/index.html

I your problem is related to LabVIEW programming or National Instruments products generally, I 'll be more able to help you.

Cordially,