D/A conversion
PESIT, BSC
Every time I think of LD!
So, what can we do?
Lets make it
FUn ! :) :)
[ yes, that's possible! ]
Happy times ahead . . .
D/a converter
Wanna see something cool?
Go down!
Go down!
A sneakpeak with Dr. Collin
Let's get started!
Binary
equivalent
weight
??
truth table for
3bit binary signal

Sum of binary weights should be equal to one. (1)

General formula for binary weights associated with LSB:
Time for a question?
Q. What's the binary equivalent weight of each bit in a 4bit system?
Hint:
Answer: 1/15 , 2/15, 4/15 and 8/15
Resistive Dividers
What should it produce? Exactly this:
How does it work?
Nothing unusual, the resistors come into play!
 Convert LSB(s) to their analog value. ( 001 = 1, 010 =2)
 Sum up these analog values.
simple enough, right? ;)
Milliman's theorem
"The voltage between the ends of the circuit is equal to the total current entering the supernode divided by the total equivalent conductance of the supernode".
Apply the formula for the circuit above.
Binary Ladders
???
Resistive network!
Watch This!
A 3bit DAC in action. :)
Lets continue with ladder networks...
ladder output voltages
Now, we bring in the
OPAMPs
Any idea why?
Obvious, isn't it!
to
by now,
Relax with recap!

Binary weights

Resistive dividers

Binary ladders
AND, WE'RE DONE!
But before that,
What's the basic difference between analog and digital signals?
Relax! You don't have to answer this one.
Resources
2. Search for more here.
3. Great help from our text by Donald P Leach and co.
A presentation made by Abhiram Ravikumar.
(just in case you forgot! ;) )
Visit: http://techroars.blogspot.in
dac
By Abhiram Ravikumar
dac
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