about VisualAnalog

Hi Kou-san,

Yes, VisualAnalog can be used to capture and save sample data.

First, as you have already done, setup the AD9257 in operation mode so you can get a valid FFT. I see from your image of the canvas that you have already done this.

Now, from the VisualAnalog menu bar, if you navigate to the "Samples" canvas by File --> New --> Octal --> AD9257 --> Samples. Open this canvas. Follow the same procedure to setup the part to run as you already did for the FFT.

You can select which channel(s) you would like to observe by pushing the Settings button on the ADC Data Capture block within the VisualAnalog canvas.

This will bring up an ADC Capture Settings window where you can select which ADC channel(s) you would like to observe. Push OK to save your selections.

If you push the Continuous Run button () you should see a time domain waveform in the graph window. If you see the time domain waveform, you are ready for the next step. Push the Continuous Run button again to stop the capture (for now).

In the VisualAnalog Graph menu bar, push the Settings button.

This will bring up a Graph Settings Window. In the General Tab, check the box in the Data Files Field.

Then, in the Data Settings tab, check the boxes in the Data File field and specify the path and filename of where you would like to store the results.

Push the OK button and the window will close.

Now, push the Continuous Run button () again, and let it run for one or two seconds before pushing it again to stop the capture. Navigate to the file you specified and open it in a tool that can read .csv files. This file contains your captured samples.

One more item . . . Please remember to un-check the Data Files check box after you have finished capturing data.

If you do not un-check this, data will be written to your storage every time you Run, which could create unintended files and take up disk space.

Please let me know if this worked for you.

Thank you.

Doug

Hello Doug-san,

Thank you for your advice.

We made a canvas using "Samples" canvas.

It works good.

Pls refer to the attached file

Ch.A data and the input wave form.

The value of Ch.A data is 7844(max) and -8192(min).

However,the input voltage is Δ312mV.

We think (7844 and -8192) is nearly maximum value at 2’s complement.

Why?.

Sorry,many questions.

Pls advise us.

Best regards,

Kou

Hi Kou-san,

I am still thinking about this anomaly. I do not have an answer yet.

Is the signal you are applying single ended or differential?

Thanks,

Doug

Hello Doug-san,

Thank you for your reply.

Pls refer to Pag.3 on the attached file.

The input signal is differential.

Thank you.

Best regards,
Kou

Hi Kou-san,

Thank you for the information.

Here is one thing to try. If you push the Settings button on the Input Formatter block in the VisualAnalog canvas, you will get a settings window.

Please try checking the Enable Weighting check box to see what voltage is associated with the code range you are seeing.

Also, when you look at your test tone in the FFT canvas, what amplitude are you seeing in the FFT?

The AD9257 is in its power-up default state, correct?

Thank you.

Doug

Hello Dougl-san,

Thank you for reply.

Pls refer to the attached pdf.

Page 4. Check Enable Weighting box

Page 5. FFT

Page 6. ADCBase0,default state

I am a little confused.

Thank you.

Best regards,
Kou

Hi Kou-san,

I'm sorry about the trouble you are having. I'll continue investigating.

In parallel, would you please try invoking a digital reset using the ADCBase0 tab in SPIController.

Please select "Reset" as shown above, and then select "Chip run".

Does this change anything?

Doug

Hello Kou-san,

As another sanity check, please make sure that the output format in VisualAnalog matches the AD9257 format setting in SPIController.

At smaller signal amplitude where the MSB is not toggled, we might get misleading readings.

Also, you can use the VisualAnalog "Logic" canvas to see which bits are actually toggling (just like a logic analyzer) to get better insight into what is happening. Please let me know if you need more information about this.

Thank you.

Doug

Hello Doug-san,

I’m sorry for the delay in my reply.

The output format is matched.

I’ll try to use Logic canvas.

Thank you.

Best regards,
Kou

Hello Doug-san,

We can choose Alignment in Input Formatter settings.

Which should we choose between 14 or 16?.

Thank you.

Best regards,
Kou