I hope someone can help me understand the meaning of variance in this case. I am reading an old research paper by Ephraim and Malah (for my DSP project) and it says:
Knowing that $D_k$ is the FFT of white noise, what I am trying to find out is $\lambda_d(k)$. Can anyone explain to me the meaning of $E\lbrace|D_k|^2\rbrace$? I think it is the variance of a particular $D_k$ with respect to the mean, but since this is white noise, shouldn't it be zero?
Please help, I am stuck!!!!