Evaluation of the actual noise immunity of signal reception at short wavelengths

Because of the impossibility of predicting the statistical properties of useful and noise signals, the calculation of the noise immunity of communication channels is based conventionally on a priori data on the properties of useful and noise signals at the receiver input and on the use of simplifying assumptions concerning the operating principles of transmission paths. Some questions and problems associated with the application of methods for calculating noise immunity to the evaluation of the properties of an actual short-wave communication link are examined in this book. A relationship between the experimental characteristics of signals in actual short-wave communication channels and the ionospheric parameters is established, and data characterizing the changes in noise levels are discussed. It is shown that in short-wave channels, the signal and noise characteristics differ appreciably from those currently used in the calculations.