How to find digital input for given output value of a DAC ?

Thread Starter

thar07

Joined Jan 3, 2015
71
The n-bit R/2R digital-to-analog converter (DAC) has a reference of 16 V and the analog
output for the input code 1 is 15.625 mV. how to find the digital input value for the output
9.140625 V ??
 

MikeML

Joined Oct 2, 2009
5,444
Look up the concept of ratiometric. The output of a DAC is ratiometric with respect to the reference voltage.
 

Thread Starter

thar07

Joined Jan 3, 2015
71
Notice that they don't tell you how many bits the DAC is. Another question probably asks you to find that.
They asked the following two questions and I don't clearly understand what it means.
1) Draw a block diagram to interface an 8 bit ADC with 8051. Clearly show your calculations
and assumptions to use above DAC to set the ADC reference voltage 10 V and display the
result in three seven segment displays.

2)
Draw a flowchart to measure analog voltage 5 V using above ADC and DAC. Display the
result in three seven segment displays. Clearly show your calculations and assumptions.
 

isurunix

Joined Feb 3, 2015
21
The n-bit R/2R digital-to-analog converter (DAC) has a reference of 16 V and the analog
output for the input code 1 is 15.625 mV. how to find the digital input value for the output
9.140625 V ??

for code 1 : 15.625 mV

1 V : 1000/15.625

9.140625V = (1000*9.140625)/15.625 = 585

in binary : 1001001001
 

Thread Starter

thar07

Joined Jan 3, 2015
71
What don't you understand?

Still waiting to see some attempt on your part.
I don't understand the following things related to the question.

1) What is the reference voltage of DAC's (n bit R/2R).
2) How to find the number of bits in this DAC.
3) how to set reference voltage of ADC by using a DAC.

I tired find theories related abouve questions and found nothing. So I could not do anything to solve these.
 

isurunix

Joined Feb 3, 2015
21
@Bertrus

Thanks for pointing it out. Can I post a link to a site containing relevant theories ?
Sorry for my mistake. I was browsing on the same question and most probably for the same home work. So I just hoped to make it easy for him to understand.
 

WBahn

Joined Mar 31, 2012
26,398
for code 1 : 15.625 mV

1 V : 1000/15.625

9.140625V = (1000*9.140625)/15.625 = 585

in binary : 1001001001
This is the Homework Help forum, not the Homework Done For You forum.

Please do NOT just do the poster's assignment for them -- in most cases it does them little good in terms of learning the material.
 
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