A.I. Fomin, A.K. Yalin, R.A. Shevchenko

In aviation radio systems of information transfer of monitoring with a speed from units to ten Mbit/s, the mode signal OF NOISE protection, based on application of broadband signals, is not used owing to limited efficiency of signals. Really clock rate of the modern, mastered in the industry of pseudo-noise signals (IPNS), does not exceed 16-32 MHz and in case of the required information transmission rate stated above the basis of a signal is small and doesn't provide effective loosening of selective interferences. It is possible to specify some known methods of increase of noise immunity of reception in case of influence of selective interferences on a receiver input. Method of spatial filtering is [1] based on formation of dips ("zero") in the direction characteristic of the receiving antenna in the direction on a source of the noises which coordinates either are measured by a direction finder, or are measured by signal processing when using the active phased antenna grids (APAG). The second method uses "rehabilitating filter" for fight against selective interferences [2]. Methods on the basis of automatic compensating of noises [3] are developed. All specified methods allow to increase quality of reception of signals in information channel, assuming operation of subsystems of synchronization, close to the ideal. In actual practice the single narrow-band noise, commensurable on power with the useful signal, breaks operation of the timing circuit bearing that will lead to violation of operation of an information channel. Operation is devoted to research of noise immunity of the timing circuit on bearing in case of influence of the narrow-band noise rather often accompanying signal transmission in radio systems.