adc_filter

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feme_285141
Level 4
Level 4

Hello, I could say that I'm doing wrong when I measure a sine signal using a filter and I get some voltage spikes are we of that wave

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Bob_Marlowe
Level 10
Level 10
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Can you please post your complete project, so that we all can have a look at all of your settings? To do so, use
Creator->File->Create Workspace Bundle (minimal)
and attach the resulting file.

   

 

   

Bob

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feme_285141
Level 4
Level 4

here this file

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Bob_Marlowe
Level 10
Level 10
First like given 50 questions asked 10 questions asked

I have no experiences with ADC configured as left align, Did you try using right align?

   

 

   

Bob

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Anonymous
Not applicable

Looks like your signal us unsigned values and the filter is treating the values as signed.

   

That gives a spike at the signed rollover.

   

Magnus

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EvPa_264126
Level 7
Level 7
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if you comment out the line 63 the voltage spikes disappear.
difficult to understand the work Filter_SetDalign () and Set Coherency ()
 

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feme_285141
Level 4
Level 4

I did considering the filter Datasheet

   

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feme_285141
Level 4
Level 4

solve the problem, change input range Vss to vdd

   

thank you for your help

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EvPa_264126
Level 7
Level 7
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No, this is not a solution.
The problem reappears at the increase of 32,768 over the input signal.

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feme_285141
Level 4
Level 4

signal fillter

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Anonymous
Not applicable

What happens if you increase the signal amplitude so that the mximum values goes above 33000?

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feme_285141
Level 4
Level 4

It leaves very bad signal

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Anonymous
Not applicable

yes there are lessons to learn from this, what happens when an unsigned value is treated by a computation component as a signed value ?

   

If the signal stays in the range of the positive half of the numbers, then everything is ok, but you can only use half the signal range.

   

If the signal crosses the half range value, when the signed interpretation treats it as a maximum negative value, then the filter sees a sudden shift in signal from maximum positive to maximum negative, and there will be spikes and ringing.

   

Magnus

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feme_285141
Level 4
Level 4

decrease the sample filter in half compared to the ADC, and the image that happened shown. it  has  to do ???

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feme_285141
Level 4
Level 4

how do I give the signal with sign ???

   

mode differntial????

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Anonymous
Not applicable

It crosses the value 32768. Thats when it happens, as you clearly can see.

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EvPa_264126
Level 7
Level 7
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Hello fernnando28. I often use the filters in my projects.
So I want to use your project as a starter.
I hope it will help me to configure filters.
I wonder what your project is very easy to organize a conclusion in USBUART.
It will not create problems?
In the example, "USBFS UART Code Example" the procedure is much more complicated.

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