1
$\begingroup$

I'm trying to calculate the power of a signal and my tutor has given me this formula to do it

photo of the handwritten formula

I've spent the past while building a program and now the foundations are there it's time to implement the maths side of it. The problem is I can't actually read it. Would someone be able to transcribe it and explain it to me?

$\endgroup$
  • 2
    $\begingroup$ $P_x=\dfrac{1}{T}\sum_{t=1}^{T}x^2(t)$ $\endgroup$ – jojek Feb 13 '15 at 17:23
2
$\begingroup$

As @jojek has already said in the comments, the formula reads $$ P_\mathrm{x} = \dfrac{1}{T}\sum_{t=1}^{T}x^2(t) $$ As $t$ usually denotes continous time I find this formulation a little bit odd. What your tutor probably actually meant is $$ P_\mathrm{x} = \dfrac{1}{T}\int_{t=0}^{T}x^2(t) \mathrm{d}t $$ It calculates the average power of the (continous-time) signal $x(t)$ of length $T$. In computer programs we're dealing with discrete-time (and discrete valued) signals, of course and the average power of the digital signal $x_n$ is given by $$ \tilde P_\mathrm{x} = \dfrac{1}{N}\sum_{n=1}^{N}x_n^2, $$ where $N$ is the length of $x_n$ in samples.

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.