ADC help§

[samiti]

hello all,

Actually i'm working on ADC characterisation( STM32's ADCs ),for that reason i have to calculate INL ,DNL,SNR,THD...

my problems are:

1- i've found many VIs on this forum , they calclate all these parameters but they all use SIGNAL palette for FFT,POWER SPECTRUM,SINAD calculations, my problem is that i have the 2010 LABVIEW basic version without SIGANL PALETTE which i've to pay get it(i can't afford it) that's why i've got to make my own VIs to calculate FFt,POWERSPECTRUM....i'm new in labview and please i need help with all those calculations could someone help me with one of these parameters(FFT for exemple) so i can understand it, to make my own other VIs???????????

2-parameters as frenquency, number of samples must be added to command the stm32 ADC, is there any specification about sampling rate to calculate any prameter(for example my be SNr calculation must be calculated with specific number of samples and at specific frequency) so could someone please explain to me the importnace of these parameters and how can i choose them??

3-I've posted a vi on which i work actually: i've simulated an ADC and created a histogram in order to represent the digital data resulting from ADC conversion, but the histogram seems to give a wrong result(i'm confsued with how much samples i must use to give a good histogram presentation)

NB: this histogram will help me in my DNL/INL gain and offset calculation,if some one has an idea of how to fix this?

i know that this is too much but i'm really confused ,and i have to expose my work on 03 of november(it's a project at my college's laboratory), so please any help would be wellcome,i'd be greatfull if any one help me

BEST REGARDS,

SAM

[samiti]

hello all,

Actually i'm working on ADC characterisation( STM32's ADCs ),for that reason i have to calculate INL ,DNL,SNR,THD...

my problems are:

1- i've found many VIs on this forum , they calclate all these parameters but they all use SIGNAL palette for FFT,POWER SPECTRUM,SINAD calculations, my problem is that i have the 2010 LABVIEW basic version without SIGANL PALETTE which i've to pay get it(i can't afford it) that's why i've got to make my own VIs to calculate FFt,POWERSPECTRUM....i'm new in labview and please i need help with all those calculations could someone help me with one of these parameters(FFT for exemple) so i can understand it, to make my own other VIs???????????

2-parameters as frenquency, number of samples must be added to command the stm32 ADC, is there any specification about sampling rate to calculate any prameter(for example my be SNr calculation must be calculated with specific number of samples and at specific frequency) so could someone please explain to me the importnace of these parameters and how can i choose them??

3-I've posted a vi on which i work actually: i've simulated an ADC and created a histogram in order to represent the digital data resulting from ADC conversion, but the histogram seems to give a wrong result(i'm confsued with how much samples i must use to give a good histogram presentation)

NB: this histogram will help me in my DNL/INL gain and offset calculation,if some one has an idea of how to fix this?

i know that this is too much but i'm really confused ,and i have to expose my work on 03 of november(it's a project at my college's laboratory), so please any help would be wellcome,i'd be greatfull if any one help me

BEST REGARDS,

SAM

[altenbach]

Is this a research project or part of an educational course for students? 

You say you are at a college. The academic version of LabVIEW (full) costs less than 10% more than LabVIEW (base), which seems insignificant and I don't understand why only LabVIEW base was purchased.

For educational use, and if you are a student, the LabVIEW student edition contains all the signal processing you possibly need and is only $20.

[samiti]

hi altenbach

thank you for your quick response,so i'm going to explain to you this situation:

in my college laboratory we can choose a topic,work on it and then present it, i have talked with the responsible and i have asked him to contact NI in order to provide us this signal palette, he aswred me that i've to find a solution by myself and that i have to find  another alternative to this palette so i've got to find a way out to do all those calculations by myself, he was kind of challenging me but it didn't bother me ,i'm working hard right now because i'm new in labview and begining with such project seems to me so hard, but i hope i'll find a solution with the help of cooperating NI forum members 🙂

[samiti]

Hello all, i'm working actually on ADC characterisation and testing, i'm refering to a document example 3 page 5 (JOINED BELOW) in which i've found how to calculate DNL from a histogram. the problem is that the result given in the example is different from my VI's result, in addition i'm really confused about the wright frequency to choose for the input signal, the sampling rate for a 3bit ADC resolution, also how can i chose the Vref value? so can someone please help me with this??? BEST REGARDS,

[altenbach]

I think you forgot a link or attachment.

And why is your question marked as solution?

[samiti]

oh god !!i'm doing all wrong these days 😞 

i've forgotten those links and markedf my own question as solution!!! my apologies ,,so these are my vi and the document i refered to,, please i don't want to make you guys think that i want to to do the work i'm supposed to do but,the only thing i need is some advises about adcs and ,if it is possible to guide me to have my expected results.

hope someone could be interested by my problem,

Regards,,

SAM.

[samiti]

Hello all!

any suggestions????

[JÞB]

I added some comments in the Block diagram

You need to code with Help on while learning-  Ctrl+H will give you some pointers to functions

[samiti]

hi jeff,

i have labview 2010 version could you please send me a vi compatible with this version??

thank you for your help.

[JÞB · Accepted solution]

here you are