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

Discussion in 'Homework Help' started by thar07, Feb 3, 2015.

  1. thar07

    Thread Starter Member

    Jan 3, 2015
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    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 ??
     
  2. MrChips

    Moderator

    Oct 2, 2009
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    If 1 count is 15.625mV how many counts in 9.140625V?
     
  3. thar07

    Thread Starter Member

    Jan 3, 2015
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    It did not give any other details. If you could please explain the theory behind this.
     
  4. MrChips

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    If one potato weighs 100g how many potatoes in a 1kg bag of potatoes?
     
  5. WBahn

    Moderator

    Mar 31, 2012
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    What will be the analog output for the input code of 2? Of 3?

    See the pattern?
     
  6. thar07

    Thread Starter Member

    Jan 3, 2015
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    if that so, why they given the reference voltage ?
     
  7. MrChips

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    Oct 2, 2009
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    Just to throw you off track.
     
  8. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    The reference value might be the maximum obtainable voltage.

    Bertus
     
  9. MikeML

    AAC Fanatic!

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

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    Mar 31, 2012
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    Notice that they don't tell you how many bits the DAC is. Another question probably asks you to find that.
     
  11. thar07

    Thread Starter Member

    Jan 3, 2015
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    They asked the following two questions and I don't clearly understand what it means.
     
  12. WBahn

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    Mar 31, 2012
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    What don't you understand?

    Still waiting to see some attempt on your part.
     
  13. isurunix

    New Member

    Feb 3, 2015
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    for code 1 : 15.625 mV

    1 V : 1000/15.625

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

    in binary : 1001001001
     
  14. thar07

    Thread Starter Member

    Jan 3, 2015
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    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.
     
  15. bertus

    Administrator

    Apr 5, 2008
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  16. isurunix

    New Member

    Feb 3, 2015
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    @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.
     
  17. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    Yes, linking to websites with the theoretical background are fine.

    Bertus
     
  18. thar07

    Thread Starter Member

    Jan 3, 2015
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    Do you have any theory notes related to this ?
     
  19. isurunix

    New Member

    Feb 3, 2015
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    @thar07 You can find the relevant theories here and here

    I found them today. These seems to be good. Hope it will help them.
     
  20. WBahn

    Moderator

    Mar 31, 2012
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    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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