ADS131E04: External clock and sample rate

Stefano Infante

Part Number: ADS131E04

Hello!

I am using ADS131E04 to sample three devices. I am counting on the fact that with a 2.048 MHz external clock the sample rate should be exactly 4000 Hz, with the same accuracy.

Is that true, or should I expect some differences in the sample rate (say, 4000.032 Hz or so)?

Thanks in advance.

Stefano

over 7 years ago

0 Alexander Smith over 7 years ago

TI__Guru 55342 points

Hello Stefano,

Thank you for your interest in the ADS131E04!

Number of samples is a finite value, so it will be exactly 4000SPS.

Additionally, the CONFIG1 register (page 41 of datasheet) sets the sampling rate in kSPS (thousand Samples Per Second), not the value of the external clock.

0 Stefano Infante over 7 years ago in reply to Alexander Smith

Expert 2320 points

Hi Alex,

thanks for your reply.

My doubt was due to the fact that the input external clock is a 2-based one (2.048 MHz), while the sample clock is a 10-based one.

As I see some slight delay in my 4000 samples, there should be something else I have to investigate on.

Thanks again

Stefano

0 Alexander Smith over 7 years ago in reply to Stefano Infante

TI__Guru 55342 points

Hello Stefano,

You're welcome and I completely understand!

Do you mean that you see some delay from when the signal is applied to the input to when the digitized codes appear at the output?

If so, this paper by a colleague of mine may be useful: www.ti.com/.../slyy095a.pdf

Hope this helps and have a good day!

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ADS131E04: External clock and sample rate