ADC speed?

ESP_Sprite
Posts: 1762
Joined: Thu Nov 26, 2015 4:08 am

Re: ADC speed?

Postby ESP_Sprite » Wed Apr 18, 2018 8:45 am

There's no filter we put intentionally in the signal path. The bandwidth of the ADC just is more-or-less 6KHz if you want a linear frequency response.

Archibald
Posts: 95
Joined: Mon Mar 05, 2018 12:44 am

Re: ADC speed?

Postby Archibald » Wed Apr 18, 2018 10:04 am

Within the Arduino IDE and using the micros() function to time ADC sampling, I am measuring the sampling time to be close to 9.5μs (including storing measurements in an array).

Do we know if ESP32s contain sample-and-hold capacitors like the Atmel chips? If not, one wonders how well the successive approximation works with high-frequency high-amplitude signals. I have not found any mention of sample-and-hold in the Technical Reference Manual.

bobolink
Posts: 19
Joined: Mon Feb 26, 2018 4:17 pm

Re: ADC speed?

Postby bobolink » Wed Apr 18, 2018 2:40 pm

There's no filter we put intentionally in the signal path. The bandwidth of the ADC just is more-or-less 6KHz if you want a linear frequency response.


Oh, OK. So it could be things like layout within the chip or something that limits to 6KHz.

I add an external anti-alias analog filter to limit the bandwidth to speech (4KHz) so I should be OK. I saw all these 44.1 KHz projects and wondered what was going on. Maybe they equalize.

Thanks

eric.osowski
Posts: 1
Joined: Wed May 09, 2018 2:17 am

Re: ADC speed?

Postby eric.osowski » Wed May 09, 2018 2:36 am

Hello, how are you?
You said that are have a vibration analysis project. I'm reseaching about the same project, for my final papper of Electrical Engineering.
I thought that ASP 1115 could do the job, but I didn't see that its SPS is very low.
Now,I have the same issue than you.
So the question is, did you find a solution for the rate of samples? I beliave that have to be biger than 30kSPS, what do you think?
could you help me?
if yes, my e-mail is eric.osowski@hotmail.com
if not, thank you anyway =)
Thanks.

Strontium
Posts: 11
Joined: Sat Dec 26, 2015 11:33 pm

Re: ADC speed?

Postby Strontium » Wed Jul 11, 2018 3:32 am

I am working on a development module that will have (among other things) 7 ADC inputs capable of 12 bit @ 1Msps. I am just finishing the layout now and will post more information elsewhere, however if you are interested in a small ESP32 based module with this feature drop me a PM and i will keep you updated.

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