Difference between square wave and digital signal?

Is there any difference between square wave and digital signal because we call square wave as A.C signal? Seeing both waveforms, we can't distinguish those?How do they differ from each other technically? And I also want to know about Unipolar and bipolar signal? Please explain in detail. Thanks in advance. show more Is there any difference between square wave and digital signal because we call square wave as A.C signal?
Seeing both waveforms, we can't distinguish those?How do they differ from each other technically?
And I also want to know about Unipolar and bipolar signal?
Please explain in detail.

Thanks in advance.
Update: I have understood what you are explaining
but the other doubt is, Bipolar and Unipolar both are square wave?

Thanks for help.
Update 2: Means bipolar signal with +10 volt have
+5 v on positive side and -5 V on negative side.

and unipolar signal with same magnitude have +10 v on positive side and 0 v on negative side.

Is it true?
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