An introduction

Digital Signal

As we know about the discreet signal in which we discreet the independent variable(x-axis).

We can find the change in x-axis by any two consecutive terms i.e. Tn-T(n-1).

Which means we discreet time or x-axisTe digital signal is the signal in which we

discreet magnitude and time both (x-axis and y-axis)

We divide the magnitude axis(y-axis) into the fix number of levels.

Lets have a look at the example.

Digital signal

In case of analog we are independent of variable . i.e.o

In the give graph you can note that x- axis isin equal parts.

But the y axis is notNow if we divide y axis

in equal parts thenthe graph will be as .

Analog Graph

Digital Graph

In the above graph we divide y-axis in three equal parts of difference 15.

Please not that digital signal take values at these levels only i.e. 0, 15,30,45.

Now lets have a look at the table values of analog and digital signal values.

Explanation

Table Values

The white one is the Discreet Time Signal and yellow one is Digital Signal.

As it is easy to understand the table of D.T.S whereas digital is a little bit different.

As I told you signal can have value equals to levels only.

If there is the value between the two levels then we have to chose the minimum value.

For example at t2 we have 38 but the level is 30 or 45 so we will take 30.

Table Explanation

Lets have a graph of voltage-time.

Error Handling

Know in this graph we have error of two voltages.

The observed values is 2 but the digital value is 0.

How do we over come this error?This error is very easy to resolve just increase

the number of levels.The more number of levels will give you the

most accurate answer.Lets at this graph if we change levels to 1.25

difference or difference of 1.

Errors

Debuged Graph

In the above at 1.25 error is of 0.75 and at 2 there is no error.

Keep in mind that we can have only levels values.

Next slide will be about digital and analog watch.

Why analog watch is called analog and why digital watch is called digital.

That’s all for this slide.Thank you Allah Hafiz.

Important