Discussion in "General help Guidance and Discussion" started by    ammi_paranjpe    Dec 19, 2009.
Sat Dec 19 2009, 12:56 PM
what does it mean actually?like 8 bit resolution,10bit resolution............and what is step size?if analog vtg is 5v then then hw to mesure step size?...................plz help...i m really nt getin this....
Sat Dec 19 2009, 07:28 PM
If you have an A/D converter reading an analog voltage, with a reference voltage of 5 volts, your reading will be "referenced" to this 5 volt value.

For instance, if you input voltage is 4 volts, then you are reading 80% of your reference voltage, right? (4/5 is 80%)

The resolution, or "how well you can resolve" this reading, is described in bits. An 8-bit A/D divides up the reference voltage into 8-bits, or 256 equally spaced voltages, from 0 to 5 volts. This corresponds to about 19.5mV per bit.

So how accurately can you measure the 4 volt signal? Well, 80% of 256 is 204.8, but you don't get any fractional bits when you read, so you will read 205. And what is the value of 205? 205/256 = 80.078125% of 5V, or 4.00390625V. Not too bad, right? Less than 0.1% error...

But what if your input voltage was 4.01V? 4.01/5 = 80.2%, which works out to 205.3, but remember? No fractional bits, so you would read 205 - But that's the same as before, right? So you would again read 4.00390625V even when the input was 4.01.

Here is where the step size comes into play - the size of the voltage step between bits is the step size.

With a 5V reference, the step size is 19.5mV, because 5V/256bits = 19.5mV

What about a 10 bit A/D? 10 bits is 1024 steps, so...
with a 5V reference, the step size is 4.9mV, because 5V/1024 = 4.9mV

What about a 12 bit A/D? 12 bits is 4096 steps, so...
with a 5V reference, the step size is 1.2mV, because 5V/1024 = 1.2mV

... and so on, and so on...

Clearly, these values are targets, and things like noise and voltage stability will play an important factor in how accurately you can read a signal, but I hope this clears up the concept...

 ammi_paranjpe like this.
Tags ADC workingHow ADC worksAnalog to digital converter
Sun Dec 20 2009, 06:25 AM
thank u so much..........nw i gt it.......u even cleared ma doubt regardin referance vtg also.....
Tue Dec 22 2009, 02:26 AM
You are most welcome!

Good luck with your projects...

Get Social


Powered by e107 Forum System


Wed Apr 21 2021, 01:25 AM
Rolland Crocker
Quit paying thousands of $$ for ripoff Facebook ads! I can show you a platform that costs only a minute bit of money and creates an almost indefinite amount of web visitors to your website}
Tue Apr 20 2021, 07:00 AM
Wow, awesome blog layout! How long have you ever been blogging for? you make running a blog glance easy. The overall glance of your website is wonderful, let alone the content material! https://1xbet-rabochee-zerkalo.best/ 1xbet рабочее на сегодня прямо сейчас рабочий зеркало 1xbet
Mon Apr 19 2021, 06:46 PM
Great work! That is the kind of info that are supposed to be shared around the net. Disgrace on Google for now not positioning this post higher! Come on over and talk over with my web site . Thanks =) https://1xbet-rabochee-zerkalo.best/ 1xbet рабочее на сегодня прямо 1xbet рабочее на сегодня
Mon Apr 19 2021, 04:30 AM
Hello superb website! Does running a blog similar to this take a lot of work? I've very little expertise in programming but I was hoping to start my own blog soon. Anyhow, if you have any suggestions or tips for new blog owners please share. I understand this is off subject nevertheless I just wanted to ask. Cheers! http://blog.bestwp.live/page.php?sitemap=yellow Williams
Sun Apr 18 2021, 05:31 PM
Brandy Levi
{{Looking for|Want to find|Want to get|Do you need} more {buyers|clients|people ready to buy|customers|serious customers|business} {for your site|for your website|for your website or online store|for your online business}? {We can provide|We can get you|We can deliver} {targeted|keyword targeted} {traffic|visitors|people} {specifically|precisely} {for your business model|for your specific type of business|for your business|for your type of business}



Thu Jun 25 2020, 03:46 PM
Mon Jun 22 2020, 03:03 PM
Tue Jun 16 2020, 05:10 PM
Sat Jun 13 2020, 09:43 PM
Thu May 21 2020, 12:44 PM
Thu May 21 2020, 01:28 AM
Wed May 20 2020, 07:05 PM
Wed May 20 2020, 11:52 AM


Guests: 97, Members: 0 ...

most ever online: 182184
(Members: , Guests: 182184) on 06 Aug 2010: 05:37 AM

Members: 38215
Newest member: Mirza123