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Re: [AVR-Chat] problem in adc accuracy

2008-04-02 by rakesh modi

thanks for ur reply,
i like to tell u that i am here measuring a dc signal. so how can i get proper accuracy?
 
R.P.Modi

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----- Original Message ----
From: Sander Pool <sander@tungstentech.com>
To: AVR-Chat@yahoogroups.com
Sent: Wednesday, 2 April, 2008 6:14:35 AM
Subject: Re: [AVR-Chat] problem in adc accuracy

Shift 2 bits maybe? Unless you meant to throw away the 2 LSBs from the 
converter? Of course when averaging the readings you need to keep Mr 
Nyquist in mind and make sure you're sampling fast enough for the 
frequency domain of your signal.

Sander

BobGardner@aol. com wrote:
>
> Add 16 samples and right shift total 4 bits
> ============ ========= ========= =======
>
>
>

      Meet people who discuss and share your passions. Go to http://in.promos.yahoo.com/groups

[Non-text portions of this message have been removed]

RE: [AVR-Chat] problem in adc accuracy

2008-04-02 by Raymond Hurst

It's only as accurate as the resolution of the ADC.

How much inaccuracy are you experiencing?

 

Ray Hurst

Western Digital

20511 Lake Forest Drive

Lake Forest, CA 92630

949-672-9853

 

 

________________________________

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From: AVR-Chat@yahoogroups.com [mailto:AVR-Chat@yahoogroups.com] On Behalf
Of rakesh modi
Sent: Wednesday, April 02, 2008 7:50 AM
To: AVR-Chat@yahoogroups.com
Subject: Re: [AVR-Chat] problem in adc accuracy

thanks for ur reply,
i like to tell u that i am here measuring a dc signal. so how can i get
proper accuracy?

R.P.Modi

----- Original Message ----
From: Sander Pool <sander@tungstentech.com
<mailto:sander%40tungstentech.com> >
To: AVR-Chat@yahoogroups.com <mailto:AVR-Chat%40yahoogroups.com> 
Sent: Wednesday, 2 April, 2008 6:14:35 AM
Subject: Re: [AVR-Chat] problem in adc accuracy

Shift 2 bits maybe? Unless you meant to throw away the 2 LSBs from the 
converter? Of course when averaging the readings you need to keep Mr 
Nyquist in mind and make sure you're sampling fast enough for the 
frequency domain of your signal.

Sander

BobGardner@aol. com wrote:
>
> Add 16 samples and right shift total 4 bits
> ============ ========= ========= =======
>
>
>

Meet people who discuss and share your passions. Go to
http://in.promos.yahoo.com/groups <http://in.promos.yahoo.com/groups> 

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

Re: [AVR-Chat] problem in adc accuracy

2008-04-02 by David VanHorn

On Wed, Apr 2, 2008 at 10:49 AM, rakesh modi <get_rak20ec@yahoo.com> wrote:
> thanks for ur reply,
> i like to tell u that i am here measuring a dc signal. so how can i get proper accuracy?

You really aren't giving people enough to work with.
Why do you think you are not getting "proper" accuracy?
What ARE you getting?
What is your input?
How did you configure the ADC?
How accurate is your reference?
How do you know what the input is, really?

Re: [AVR-Chat] problem in adc accuracy

2008-04-02 by Dennis Clark

> On Wed, Apr 2, 2008 at 10:49 AM, rakesh modi <get_rak20ec@yahoo.com>
> wrote:
>> thanks for ur reply,
>> i like to tell u that i am here measuring a dc signal. so how can i get
>> proper accuracy?
>
> You really aren't giving people enough to work with.
> Why do you think you are not getting "proper" accuracy?
> What ARE you getting?
> What is your input?
> How did you configure the ADC?
> How accurate is your reference?
> How do you know what the input is, really?

  And the impedance of that you're reading.

DLC

-- 
Dennis Clark
TTT Enterprises

Re: problem in adc accuracy

2008-04-04 by jverive

Lots of factors contribute to ADC accuracy, including (but not limited to):
power supply ripple, voltage reference (level, accuracy, short term stability, drift), internal electrical noise, external noise, load, temperature, and others.  What specific problems are you having?

Jeff Verive

   --- In AVR-Chat@yahoogroups.com, rakesh modi <get_rak20ec@...> wrote:

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>
> thanks for ur reply,
> i like to tell u that i am here measuring a dc signal. so how can i get proper accuracy?
>  
> R.P.Modi
> 
> 
> 
> ----- Original Message ----
> From: Sander Pool <sander@...>
> To: AVR-Chat@yahoogroups.com
> Sent: Wednesday, 2 April, 2008 6:14:35 AM
> Subject: Re: [AVR-Chat] problem in adc accuracy
> 
> 
> Shift 2 bits maybe? Unless you meant to throw away the 2 LSBs from the 
> converter? Of course when averaging the readings you need to keep Mr 
> Nyquist in mind and make sure you're sampling fast enough for the 
> frequency domain of your signal.
> 
> Sander
> 
> BobGardner@aol. com wrote:
> >
> > Add 16 samples and right shift total 4 bits
> > ============ ========= ========= =======
> >
> >
> >
> 
>  
> 
> 
>       Meet people who discuss and share your passions. Go to http://in.promos.yahoo.com/groups
> 
> [Non-text portions of this message have been removed]
>