# A/D Converter

#### hncelectronics123

Joined May 23, 2008
10
Hello again Guys

Another question id like to ask is;

I have an output from an analogue device of 0.699mV

Using An 8bit A/D converter work out the output.

#### Dave

Joined Nov 17, 2003
6,970
What is the ADC range? Is the ADC linear or non-linear?

Dave

#### hncelectronics123

Joined May 23, 2008
10
The ADC is Linear yes.

The only other information i have on it is

Number of bits = 8
Input to achieve ful scale output = 4 volts

Does this help?

Thanks

#### hncelectronics123

Joined May 23, 2008
10
Ok i have worked out the Resolution of the A/D converter.

8 bits = 256 codes

full scale output = 4v

so....... 4v/256codes = 15.62mV

Can anybody work out the final output of the A/D converter if the input is 0.699mV

#### bertus

Joined Apr 5, 2008
20,650
Hello,

In you first post you say 0.699V and in the last 0.699mV.
With 0.699V ( that is 699 mV ).
Per step you calculated 4 V / 256 = 15.625 mV
If you divide 699 mV / 15.625 mV you will get 44.736.
Depending on the accuracy you will get 44 or 45 as a digital value.

Greetings,
Bertus

#### Dave

Joined Nov 17, 2003
6,970
The ADC is Linear yes.

The only other information i have on it is

Number of bits = 8
Input to achieve ful scale output = 4 volts

Does this help?

Thanks
Yes that is the ADC range.

Ok i have worked out the Resolution of the A/D converter.

8 bits = 256 codes

full scale output = 4v

so....... 4v/256codes = 15.62mV

Can anybody work out the final output of the A/D converter if the input is 0.699mV

15.62mV is correct as the resolution.

Are you sure you want to know the output for 0.699mV? 0.699mV is considerably less than the 15.62mV resolution of the ADC; therefore an input of 0.669mV would not register a reading at the output, i.e. the output would be 00000000

If it is 0.699V and not 0.699mV, then the answer is as bertus has explained of 45 (in base 10) or 00101101 as an 8-bit binary output.

Dave

#### hncelectronics123

Joined May 23, 2008
10
Thanks alot Yeah my mistake with the mv, v thing. been along day.

So, lets say that the output of the analogue/digital converter is 45.
I understand that this is the output but can this be displayed in a binary format, Such as 11010110

Thanks very much

#### Dave

Joined Nov 17, 2003
6,970
Thanks alot Yeah my mistake with the mv, v thing. been along day.
No problem, thanks for clearing it up.

So, lets say that the output of the analogue/digital converter is 45.
I understand that this is the output but can this be displayed in a binary format, Such as 11010110

Thanks very much
45 (decimal) is 00101101 (binary) - this is the 8-bit output of the ADC for an input voltage of 0.699V.

Dave

#### hncelectronics123

Joined May 23, 2008
10
Many thanks for all your help!!!!!!
Sorry for the mistake, you are right with 0.699v.

Once again thank you very much

#### Dave

Joined Nov 17, 2003
6,970
No problems. Lets us know if you have any further queries.

Dave