Redpitaya Forum

Hi everyone

I was meassuring some simple wave forms, and somehow i got a strange meassurement i generated a 53kHz block wave and
the meassurements look a bit different in matlab than the online meassurements is there a reason why it looks different?

http://postimg.org/image/6ntgcrf21/
http://postimg.org/image/ocl74dqt5/
http://postimg.org/image/kexxez3zt/
http://postimg.org/image/54y27s8hl/

These are the meassurements i get, i anyone knows a reason why they different, and could explain why they different?

Kind regards

Wouter

Hi Wouter,
One reason I can think off is that the MatLab call in clients/matlab/acquire.m does not use the shaping and equalization filter by default, whereas the scope app does.
You could try to add the "-e" and "-s" options to the MatLab script acuire call to see if that makes a difference. The line would read something like:

Alright it works now

Thanks!

Maybe another stupid question.. but is there a specific reason why the min,max,ptp measurements are different in matlab compared to the web application? I got close its only 50mV difference ( for each waveform) but maybe there is a reason why it keeps doing this..

Kind regards

Wouter

This might have something to do with the calibration values, which the standard acquire utility ignores.

You could try the modified acquire from edgo, which applies calibration to the sampled values.
Bear in mind that the calibration in this utility is default off (so, another command line parameter) and that when switched on, the output values will be voltages, not raw samples.

Got it running Thanks for the hint.

Wouter

Hello everyone

I walked into another problem. I am now trying to get measurements in labview with the -c command, but then when i try to convert the string to a numeric it rounds the values to 0.0 e+0. Anyone knows how i can get around this problem?

http://postimg.org/image/t0bii5vil/

Thanks in advance

Wouter