Understanding Digital-to-Analogue Conversion in Signal Processing

[Taniaz]

Homework Statement

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.

Homework Equations

Four bit digital numbers being ised

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.

 

[DrClaude]

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?

What is the sampling frequency?

Secondly this graph looks like a digital graph more than an analogue graph?
I don't understand the conversion at all.

The output of the microphone is passed through an ADC.

 

[Taniaz]

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.

 

[DrClaude]

Yes and then it puts it back into a DAC.

And that DAC cannot recover any information that was lost in the A to D conversion.

 

[Taniaz]

Ah I don't know why I over complicated questions for myself.

Thank you so much!