I'm using the DC718C data collection board together with P-scope to save ADC samples and load it into MATLAB. I encountered a problem, and this can be solved by collecting more data, maybe 10x more than the maximum size (131,072 samples).
Is there any way I can collect more than 131,072 samples with P-scope, or maybe another alternative?
Hello NathanT ,
For now, I want to be able to calculate SINAD for an analog AM signal. The problem arises when the message signal strength is high; the SINAD varies by around 3dB from file to file. This is why I need more samples. Later im gonna do some test with a tetra signal.
Hello, Abdelhakim .
Here are some of my insights:
1) May we get another snapshot from the Pscope? Can you click the drop down in the size section?
2) Also, just wondering, have you made any modifications in the DC718C? Or are you using any other boards aside from our boards? Can we also get a photo of your setup? (e.g connections, power supply, etc.) This is to further asses the snapshot given.
3) We also noticed from your scope shot that you have a spurious signal at around 3.7 MHz. What are your thoughts on this? Is this unwanted? Or have you checked what caused this? If yes, can you tell us the specific reason on what caused this spurious signal?
As you can see from the figure from its datasheet, Fin used was 1MHz and samples used were only 32k. Then we should at least get a SINAD of around 94.6 dB based on these configurations.
But because of the spurious signal, it led to the degradation of the signal, resulting to a SINAD of around 24 dB. Removing the spurious signal should improve the SINAD by at least 50 dB. 
Thank you for your patience.
Warm regards,
Jo
