Signal Generators

cancel
Showing results for 
Search instead for 
Did you mean: 

PXI-5422 DC Linearity Specification

Hi,

 

I am using the PXI-5422 signal generator to generate a slow ramp (~100ms) and I would like to know how linear the ramp is likely to be.

The only DC accuracy specification supplied is " ±0.4% of Amplitude ±0.05% of offset ±1 mV " which is most likely made up of offset and gain errors only.

So, what is the DC linearity specification for this signal generator, is it true 16 Bits linear ?


Thanks,

Maurice.

 

0 Kudos
Message 1 of 5
(5,683 Views)

Hi Maurice,

 

Our devices are usually specified in terms of Gain and Offset error.

 

Gain error corresponds to Differential Non-linearity Error; that is, if a ramp signal was output by the device, that error would be the difference between the actual gradient of the ramp, and the ideal gradient.

 

Offset error corresponds to Integral Non-linearity Error; that is, if the same ramp were to be output, this error would be the vertical offset error between the actual ramp and the ideal ramp.

 

The diagram below illustrates this a lot more concisely than my words could!

 

http://www.eetimes.com/ContentEETimes/Images/Schweber/C0848/C0848-Figure2.gif

(DNL = Differential Non-linearity Error, INL = Integral Non-linearity Error).

 

These two parameters are how our devices are specified in terms of linearity. Is this different to the type of linearity measurement you are looking for?

 

If so, would you mind clarifying further what you mean by 'DC Linearity Specification'?

 

Kind regards

Josh E
Applications Engineer
National Instruments UK & Ireland
0 Kudos
Message 2 of 5
(5,663 Views)

Hi Josh, thanks for getting back,

 

I should have been more specific, it is INL error that I am interested in, In my application I have nulled the offset and gain errors, the remaining errors are INL and DNL.

If I was to draw a theoretical straight line between the two nulled offset and gain points the error I would like to know is the deviation from this line as illustrated in the diagram you attached.

 

I am guessing that inside the PXI-5422 signal generator is a DAC chip with specified INL and DNL errors, if you could let me know what these values are I would appreciate it.


Thanks,

Maurice.

 

0 Kudos
Message 3 of 5
(5,660 Views)

Hi Maurice,

 

Unfortunately we aren't able to publish these specific values on the forums, all we can publish here is what's already on our website.

 

If it's necessary that you need these specifications, can I advise you to perhaps create a Service Request with our Technical Support team? 

 

You can do this either via email or telephone, below is a link if you'd like to do that.

 

http://www.ni.com/support/

 

All the best,

 

Josh

Josh E
Applications Engineer
National Instruments UK & Ireland
0 Kudos
Message 4 of 5
(5,644 Views)

Will do, Thanks.

 

0 Kudos
Message 5 of 5
(5,642 Views)