search for: autocovarance

I need to compute the Fourier transformation of the autocovariance function of a panel composed by 196 time series. With autocovarance function i mean a matrix Gamma(u) which contains the covariance of all the variables at time (t) with all the variables evaluated at time (t-u). It can be represented by a tri-dimensional matrix whose dimensions are (196,196,K), where K is the maximum lag length I am considering (in my case 18)...