Im having a little trouble about how to go about defining this signal. It has a sqrt(-1) in it raised to a power so this is where i get confused. No doubt my poor algebra skills may be holding me back from understanding this problem.(adsbygoogle = window.adsbygoogle || []).push({});

The signal is x(k)=j^-k u(k)

I need to determine:

A. Whether or not the signal is periodic or aperiodic. If periodic what is the period?

B. Is it bounded or unbounded?

C. Finite or Infinite?

D. Calculate the power of x(k)

Im starting off with A. I know the definition of a periodic signal is if I can replace "k" with "K+N" and get the same signal. The value of N that achieves this is my period. I don't even know how to go about that with the j in there. j=square root(-1).

For a bounded signal im not sure how to really go about this one either but since there is no "bounds" defined for k i would say its bounded with a bound of 1? Im not really sure on this though.

C. I would say this is a finite signal? I think because there are no operators to make the signal reach infinity?

D. I havent attempted this yet.

I feel ill be able to deal with this problem a little bit better if i fully understand what to do with the imaginary number.

Any ideas?

Thanks,

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Defining a Signal. periodic, bounded finite etc.

**Physics Forums | Science Articles, Homework Help, Discussion**