IT1261347B - Generating correction function eliminating phase and amplitude errors in compressed signal - producing Fourier transform reference functions of ideal and optimal filters to provide correction function in time range of inverse Fourier transform - Google Patents

Abstract

To generate a reference function (hi(t)) an error-free, frequency modulated signal (So(t)), a signal (Sf(T)) containing phase and amplitude errors, a reference signal (ho(t)) corresponding to a conjugated, complex, time inverted function of the error-free signal and a reference signal (Hf(t)) corresponding to a similar function of the input signal, are each Fourier transformed. These signals are all multiplied together in twos. The reciprocal of the signal (Ff) from the first multiplication is multiplied with the output signal (Fo) from the second multiplication. The result is multiplied by the Fourier transformed signal (Hf). This is inverse transformed to give a reference function (hi(t)). A second reference function (hf(t)) is generated according to optimal filter theory. The reference functions are Fourier transformed in an FFT device (6.2, 6.5). The reciprocal (1/Hf) of one transform signal is multiplied with the other. The result is inverse transformed in an IFFT device (6.7) to generate a correction function (hkorr(t)).