Digilent Discovery 2 can't hit 100Ms/s

[Ayesha Zaman]

Good Afternoon All,

I am working on some test and analysis using Digilent discovery 2, I have designed a LABVIEW VI for Digilent MSO (Oscilloscope), in practical the FPGA could not hit the maximum sampling rate of 100 Ms/s , rather it goes uoto maximum 50 Ms/s.

Anyone would please suggest how to resolve the issue?

Thank you.

Regards

Ayesha Zaman

 

[attila]

Hi @Ayesha Zaman

Make sure the acquisition time / sample rate is not more than the device buffer size, 8192 for AD2, otherwise it will try to use record/data streaming which is limited to a few MHz for AD2.

Time (s) - mso/1    Amplitude (V) - mso/1    
0    3.97984m    
10n    3.97984m    
20n    3.97984m    
30n    -10.8283m    
40n    7.68187m    
50n    -14.5303m    
60n    3.97984m    

[Ayesha Zaman]

Thank you for the feedback !

Are you referring to Buffer size of the DUT (device under test) being tested please?

thank you

Edited April 15 by Ayesha Zaman

[Ayesha Zaman]

On 4/12/2024 at 5:09 AM, attila said:

Hi @Ayesha Zaman

Make sure the acquisition time / sample rate is not more than the device buffer size, 8192 for AD2, otherwise it will try to use record/data streaming which is limited to a few MHz for AD2.

Time (s) - mso/1    Amplitude (V) - mso/1    
0    3.97984m    
10n    3.97984m    
20n    3.97984m    
30n    -10.8283m    
40n    7.68187m    
50n    -14.5303m    
60n    3.97984m    

 

[JColvin]

Hi @Ayesha Zaman,

It is the buffer size of the Analog Discovery analog input/scope (as that is what you are using) that needs to be kept under the value.

For example, if you are wanting to acquire 10 us at 100 MS/s, that would be 1000 samples (1*10^-5 x 1*10^8). Correspondingly, the maximum amount of time for a single acquisition at 100 MHz for the AD2's 8192 sample buffer size would be 81.92 us.
If you wanted to acquire data for a longer period of time, then the sample rate has to decrease to 50 MHz (or lower, depending on the length of time) for the 8192 sample buffer to be "spread out" enough to encompass the full desired time frame.

Thanks,
JColvin