Enhancing Arduino ADC resolution with dithering & oversampling

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Squonk42
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Enhancing Arduino ADC resolution with dithering & oversampling

Post by Squonk42 » Wed Mar 01, 2017 6:21 am

https://edwardmallon.wordpress.com/2017 ... rsampling/

Not a new method, but it is nicely explained in this blog post.

I wonder how this could be applied to the STM32?

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Re: Enhancing Arduino ADC resolution with dithering & oversampling

Post by victor_pv » Thu Mar 02, 2017 2:55 pm

Squonk42 wrote:https://edwardmallon.wordpress.com/2017 ... rsampling/

Not a new method, but it is nicely explained in this blog post.

I wonder how this could be applied to the STM32?
I believe there is an STM application note describing the same for the stm32f1 series.

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Squonk42
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Re: Enhancing Arduino ADC resolution with dithering & oversampling

Post by Squonk42 » Thu Mar 02, 2017 9:01 pm

You are right @victor_pv, I found AN2668 on this matter, thanks!

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Pito
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Re: Enhancing Arduino ADC resolution with dithering & oversampling

Post by Pito » Thu Mar 02, 2017 9:47 pm

The dithering noise must be white, so I doubt you can make it with a fixed freq pwm signal.
With smaller stm32s the dithering is built in as the analog ref is hardwired to Vcc :)
Last edited by Pito on Thu Mar 02, 2017 10:02 pm, edited 1 time in total.
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Re: Enhancing Arduino ADC resolution with dithering & oversampling

Post by ahull » Thu Mar 02, 2017 9:58 pm

Pito wrote:With stm32 the dithering is built in as the analog ref is wired to Vcc :)
I like the way you are thinking :D
If you are genuinely looking to produce white noise. -> https://electronics.stackexchange.com/q ... r-analysis
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Re: Enhancing Arduino ADC resolution with dithering & oversampling

Post by Pito » Thu Mar 02, 2017 10:09 pm

@Andy: That zener noise will be 1/f one, be sure. You need white one :) ..
You can generate it by the stm32 itself - ie with an LFSR in sw.
https://en.wikipedia.org/wiki/Linear-fe ... t_register

Btw, long time back I messed with dspic33F's 12bit ADC with an external 2.5V ref, with a few 100k oversampling and subHertz low-pass fir filter (all fp). Great results. Try..
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