Carrier frequency estimation system for quadrature amplitude modulated signal converts signal into IF signal controlling complex signal generator with evaluation of Fourier transformation of complex signal

摘要

The estimation system (10) has the quadrature amplitude modulated signal converted into an IF signal (13) which is sampled at a given rate for providing a corresponding digital signal fed to a complex signal generator (14), with Hilbert transformation of the real component of the digital signal for providing an imaginary component. The complex signal provided by the complex signal generator is raised to a given level and fed to a fast Fourier transformation module (18), followed by a processor (20), providing the index of a sample value with the highest amplitide for estimating the carrier frequency relative to a target carrier frequency.