DDC11XEVM-PDK: please confirm the graph data at no signal

Hi Shinichi,

I'm reviewing my results with my team, I connected a DDC114 to one of our computers and connected one of the inputs to GND and i was seeing ~ -400 for the codes. It seems like your data is riding on a 50-60 Hz signal, can you describe more about your setup, like sensor, sampling rate and range used.

Hi Matt,

Thank you for your reply.

I confirm the customer about the setting, sensor, sanpling rate and range.

And then I'll feedback to you.

I appreciate your great help.

Best regards,

Shinichi

Hi Matt,

I checked the customer.

Firstly, the input is not connected to GND, not connected anywhere(open).

Also, the customer'd like to compare his result with another EVM.

Could you please acquire the data.

The EVM setting is listed below.

I appreciate your great help.

Best regards,

Shinichi

Hi Shinichi-san,

Just jumping in... Few things customer can do:

• Can they confirm they are shielding the EVM in a box? The inputs are very sensitive to pick-up any ambient noise
• Te picture is not very clear (where the samples are) and we don't know what is the sampling frequency, but otherwise you can just maybe measure the noise frequency in the time domain... If not, they can always do an FFT.
• To see if there is any kind of aliasing and triple check the frequency of the noise is the right one, they can change the sampling frequency...

I see no reason to compare to another EVM, as we obviously would not have released the device if this kind of artifact was there. We need to understand what are the special conditions that is driving it (disconnecting the outputs is the right and normal thing to do...)

Regards,

Edu

Hi Edu,

Thank you for your reply.

I'll share your suggestion with the customer and confirm.

If I get something new information and question, I consult you again.

I appreciate your great help.

Best regards,

Shinichi

Hi Matt and Edu,

My customer confirmed with the input connected to GND.

I was grateful if you could advise.

The waveform like a sign wave has disappeared.

I think that is due to noise from outside(may be from AC). Is it correct?

Regarding attached waveform, it is not measured in the shield box (input connected to GND), is this a normal waveform?

I appreciate your great help.

Best regards,

Shinichi

Hi Edu,

Thank you for your reply.

The customer'd like to just check whether DDC 11 x EVM is working properly.

When EVM arrived, the customer first checked the operation of DDC 11 x EVM
As a result, he saw the output which seemed to be (AC?) Noise.

Even if it is not recommended to connect the input and GND, but is it possible to comment on the customer's result by comparing  the data connected with GND Matt confirmed?

Or should the customer compare it with the data measured with the shield case entered?

I appreciate your grea help.

Best regards,

Shinichi

Yeah... We could compare it to the EVM here, but that won't help them much. Eventually they need to be able to operate the EVM free of noise (I guess), so, they do need to get a shielded box. Another quick test they can do for simple check of basic funcitonality is to apply a current at the input and see if the output DC code changes. For instance, attach one side of a resistor to the input (don't recall if the EVM already have those on board) which is virtual ground and apply a voltage to the other side of the resistor, i.e., injecting a current.

Regards,

Eduardo

Hi Edu,

Thank you for your reply.

I'll share your suggestion with the customer.

And then if he take the waveform or output data, I consult you again.

I appreciate your great help.

Best regards,
Shinichi

Hi Edu,

The customer put EVM in the can of cookie and measured as a simple shield case
The following results were obtained.

I would grateful if you could advise.

(1) waveform in the cookie can

Input pin is open.

Is this data reasonable?

Is there room for improvement?

(2) cookie can opened

Input pin is open.

(3)

Is there an actual data of the EVM in a shield case?

That data is available, it can be compared with the best condition.

---

I appreciate your great help.

Best regards,

Shinichi

Hi Edu,

The customer obtained the waveform of shielded can.

I would be grateful if you could advise.

---

(1) I put it in a candy can box and made measurements as a simple shield case

The following results were obtained.

(2)When the case was opened, the following result was obtained.

Both (1) and (2) inputs are open
Is there still room for improvement?

(3)

Could you provide a result of actually measuring the EVM by putting it in the shield case?

I' d like to use as reference and compare it with the numerical value.

---

I appreciate your great help.

Best regards,

Shinichi

Hi Edu,

This is just reminder I'm looking forward to waiting your advice.

I appreciate your great help.

Best regards,
Shinichi

Hi Edu,

Thank you for your reply.

I'll share your suggestion with the customer.

I appreciate your great help.

Best regards,

Shinichi