Alternative Autocorrelation Function for Radio Pulse Processing

Abstract

The idea of improving the methods of processing the received radio signals under intense noise used in radio communication and radar systems is considered. A method for receiving radio pulses using their autocorrelation functions ACF is presented. It makes it possible to determine the presence of a periodic signal in a mixture with intense noise, the value of the carrier frequency of the radio pulse and the value of its average amplitude. However, to calculate the ACF, many multiplication operations are required, which take much longer than addition operations. It is proposed to use a function similar to the ACF, which by its properties makes it possible to determine the carrier frequency of the radio pulse, the value of its average amplitude, the value of the average amplitude of the noise that distorts the radio pulse. When calculating such a function, the multiplication operations that are in the ACF expression are replaced by the addition operations. However, to obtain such a function, it is not necessary to have signals with a time shift, as in calculating the ACF, but the exact value of the sum of their amplitudes. In this work, this function is called the alternative autocorrelation function AAKF. Shown are the ACF and AAKF images for a radio pulse of long duration, for additive noise, and also for a mixture of a radio pulse and noise. The main properties of the AAKF mixture of a radio pulse and noise relative to the ACF are considered. The forms of AAKF and ACF are different, but their periods are the same. It is shown that a device that allows one to obtain the exact value of signal amplitudes can be constructed according to the scheme of a two-channel "ideal" peak amplitude detector, which is proposed in this work. The possibility of obtaining a periodic AAKF of a mixture of a radio pulse and noise is very briefly considered. It is shown that with the help of periodic AAKF further processing of radio pulses can be done, with additional suppression of the influence of noise. In this case, the shape of the envelope of the periodic AAKF is rectangular. This approach is better suited for processing rectangular radio bursts. To solve this problem, you can use bandpass filtering of periodic AAKF and the operation of inverting the results of calculations. It is emphasized that the considered method for calculating the parameters of the useful signal and noise can be implemented on a modern element base when transferring a signal to an intermediate frequency, but this requires a large time delay in obtaining the results.