Definition: | for a quantity having a continuous spectrum and a finite mean power, limit, at any frequency, of the quotient of the power within a frequency band containing that frequency by the bandwidth when the bandwidth tends to zero NOTE 1 The instantaneous power of a quantity is by convention equal to the square of its instantaneous value. This square is proportional to a physical power if the considered quantity is a field quantity. NOTE 2 The power spectral density is the Fourier transform of the autocorrelation function.
|