# What does "x(n) is complex" mean? (DSP)

I am new to EE area and I met a question in my homework: Can someone help me a little bit? I think it is quite easy!

Thanks!!

• It means they can take complex values.
– MBaz
Sep 21 '17 at 1:11
• @MBaz, Short answers are still answers :) (This question cannot be closed as off-topic, unclear or too-broad, so if not closed as answered it will be circulating for ever :/ ).
– A_A
Sep 21 '17 at 8:54
• @A_A I hope you don't mind: I edit your comment to link to meta. :-)
– Peter K.
Sep 21 '17 at 12:52
• @A_A I didn't put it as an answer since I thought I had misunderstood the question :)
– MBaz
Sep 21 '17 at 13:18

It means that $x(n)$ and $y(n)$ can be complex numbers rather than just real numbers. As a result there is no conjugate symmetry in the Frequency domain for these signals. Note that part (c) the asterisk in $x^*(n)$ usually means to take the complex conjugate. If $x(n)$ and $y(n)$ were real, i.e. not complex, then (b) and (c) would be equivalent.