Real time H.F. Channel estimation

The necessity of real time H. F. channel estimation for fully controlling an adaptive system is shown in this thesis. The use of C. W. pilot tones for channel estimation is discussed in detail. The phase perturbations and amplitude variations of a received C. W. pilot tone, propagating through the ionosphere, are analysed to give direct measurement of the propagation parameters. The effect of propagation conditions on the signal distribution is discussedand introduced In the analysis. The general expressions, which define each type of propagation condition, are deduced and the theoretical values are computed. The practical implementation using a microprocessor technique is shown. The practical results obtained by laboratory simulation are compared with the theoretical analysis for the different types of propagation conditions.