dc offset removal

[Sharmi]

Hi,

I want to remove the dc offset from a signal, I checked the Basic DC RMS vi but it will subtract the mean(DC) from the original signal. 
Is there any way I can remove the offset?

Thanks so much,

Sharmi

[GregFreeman]

Can you do it in hardware? Or does your hardware you are acquiring the data with support this option

[Sharmi]

I am acquiring the data in PXI 5663.

Is there any vi that can remove dc offset?

Thanks,

Sharmi

[GregFreeman]

Can you give more detail? Is this a signal you've already acquired and you want to take out the DC component? Or are you talking about removing the DC component from future acquistions at the time the data is acquired?

If it's the later, what you need is AC coupling but I'm not sure if that device has it. I'm assuming it doesn't because if you read one of the articles I linked before, it states that in general most devices except S series and DSA devices don't have AC coupling. 

That said, why not use a high pass filter, which will essentially eliminate the 0 frequency component?

Sometimes you need to look at data sheets. Other times Google will give you an answer if you just type in your question. Furthermore, you can search the forums and find this answer on here. Don't give up so quickly on finding an answer yourself!

[crossrulz]

You want to remove the DC offset before digitizing with the DAQ?  Simply put a capacitor in series with the DAQ input.  A simple ceramic 1uF should more than work for you.

[GregFreeman]

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@crossrulz wrote:

You want to remove the DC offset before digitizing with the DAQ?  Simply put a capacitor in series with the DAQ input.  A simple ceramic 1uF should more than work for you.

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A smart man to explicitly write it...I guess I need to stop putting links and start writing the solutions because it seems the OPs only look at them about 50% of the time 

[crossrulz]

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@for(imstuck) wrote:

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@crossrulz wrote:

You want to remove the DC offset before digitizing with the DAQ?  Simply put a capacitor in series with the DAQ input.  A simple ceramic 1uF should more than work for you.

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A smart man...I guess I need to stop putting links and start explicitly writing the solutions because the OPs usually look at them only about 50% of the time.

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I've had to do this enough times.  Just as much fun is removing the AC component of a signal (hint:  use an inductor in series, it's called an RF Choke).  I will admit here that these are typically not what you want to do.  Usually you want to characterize the signal or look for a specific frequency band.  For that, you need to build a real filter.

[erick.rodriguezoa]

Hi @crossrulz I have a NI DAQ USB6009 to record some photo detected signal at 60 hz, I want to quit the offset and keep an AC signal, the 1uF capacitor didn't work. After some calculation considering the real resistance of 1.7 M Ohms the Capacitor should be Around 4 nF but no capacitor seems to work, in fact with any capacitor the signals disappear and leaves just noise, if I disconnect the temrinal is the same. 

what can you suggest for performing this?