# Is any digital signal comprised of one or more discrete signals?

Is any digital signal comprised of one or more discrete signals?

i.e. one discrete signal or two or more discrete sub-signals?

• Your question makes no sense to me. I think you're making some assuptions that you're not mentioning. Could you try clarifying in what sense a signal might be comprised of other signals? What do you mean by "digital" and by "discrete" -- is it in time or in amplitude?
– MBaz
Mar 21, 2022 at 22:56
• @MBaz I define digital signal as a signal which is discrete both time and amplitude. Mar 22, 2022 at 3:20
• @MBaz so yes I understand, if it's discrete only in time but not in amplitude it will be just "discrete signal" and not "digital signal" right? Mar 22, 2022 at 4:36
• I mean, you can always take a digital signal and split it into even and odd samples, both of which will also be discrete sub-signals... Mar 22, 2022 at 6:31

As far as decompositions, we can express any digital signal or any discrete-time signal as one or more of the same kind of signal (just as we can express $$5$$ as being $$3+2$$). Given the conditions above, we see however that we cannot express any discrete-time signal as being a sum of one or digital signals since the discrete-time signals can have non-rational magnitudes while a digital signal cannot. (We can only approximate which leads to the whole theory of quantization noise).