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Homework Help: Digital to Analogue graphs

  1. May 8, 2017 #1
    1. The problem statement, all variables and given/known data

    The digitial signal is transmitted and then converted to an analogue form by the DAC. Using data from Fig. 12.2, draw on the axes of Fig.12.3, the output level of the transmitted analogue signal for time zero to time 1.2 ms.

    2. Relevant equations

    Four bit digital numbers being ised

    3. The attempt at a solution

    The solution of the graph is attached. I don't understand how they knew the graph will be constant between 0-0.2 and then 0.2-0.4. How did they calculate this? Secondly this graph looks like a digital graph more than an analogue graph?
    I don't understand the conversion at all.

    Thank you for your help.

    Attached Files:

  2. jcsd
  3. May 8, 2017 #2


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    Staff: Mentor

    What is the sampling frequency?

    The output of the microphone is passed through an ADC.
  4. May 8, 2017 #3
    It's 5kHz which I understand now so it's measuring it after every 2 ms which is why the intervals as such.

    Yes and then it puts it back into a DAC.
  5. May 8, 2017 #4


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    Staff: Mentor

    And that DAC cannot recover any information that was lost in the A to D conversion.
  6. May 8, 2017 #5
    Ah I don't know why I over complicated questions for myself.

    Thank you so much!
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