Importance to be in Full Scale for ADC

Guest
Why is it important to be full scale when performing the analog-to-
digital conversion?
 
On Wed, 08 Oct 2008 09:44:11 -0700, sntabiri wrote:

Why is it important to be full scale when performing the analog-to-
digital conversion?
Better resolution.

Hope This Helps!
Rich
 
On Wed, 8 Oct 2008 09:44:11 -0700 (PDT), sntabiri@gmail.com wrote:

Why is it important to be full scale when performing the analog-to-
digital conversion?
---
Because you'll lose resolution if you aren't.

Consider:

If you have an 8 bit ADC with an input range of zero to one volt it'll
output 00000000 with an input of 0V and 11111111 with an input of 1V.

If you have a signal which varies from zero to 0.5V and you connect it
to the ADC input, then the best you'll ever get out of the ADC will be
01111111, so instead of being able to resolve 256 different states
corresponding to input voltages you'll only be able to resolve 128.

In some applications it may not be important, but for those where it is
the usual route is to amplify the signal so that it covers the
full-scale input of the ADC or to select the ADC reference so that the
input signal's excursion causes a full-scale change in the ADC output.

JF
 
On Oct 8, 5:14 pm, Rich Grise <r...@example.net> wrote:
On Wed, 08 Oct 2008 09:44:11 -0700, sntabiri wrote:
Why is it important to be full scale when performing the analog-to-
digital conversion?

Better resolution.

Hope This Helps!
Rich
Thank you, Rich.
 
On Oct 8, 5:15 pm, John Fields <jfie...@austininstruments.com> wrote:
On Wed, 8 Oct 2008 09:44:11 -0700 (PDT), sntab...@gmail.com wrote:
Why is it important to be full scale when performing the analog-to-
digital conversion?

---
Because you'll lose resolution if you aren't.

Consider:

If you have an 8 bit ADC with an input range of zero to one volt it'll
output 00000000 with an input of 0V and 11111111 with an input of 1V.

If you have a signal which varies from zero to 0.5V and you connect it
to the ADC input, then the best you'll ever get out of the ADC will be
01111111, so instead of being able to resolve 256 different states
corresponding to input voltages you'll only be able to resolve 128.

In some applications it may not be important, but for those where it is
the usual route is to amplify the signal so that it covers the
full-scale input of the ADC or to select the ADC reference so that the
input signal's excursion causes a full-scale change in the ADC output.

JF
Hi! JF,

Thank you the detailed explanation.
 

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