Ionospheric Dispersion Effect Simulator

Abstract

The invention brings forward an ionosphere dispersion effect simulator. The scheme of the simulator is as follows: two stages of finite impulse response digital filters FIR1 and FIR2 are arranged in an FPGA. A digital intermediate-frequency signal that has been converted by an analog-to-digital (A / D) converter is processed by the first-stage finite impulse response digital filter FIR1 to complete balancing of channel initial group delay; and then the second-stage finite impulse response digital filter FIR2 is used for completing approaching of a dispersion effect curve determined by an objective function. A DSP carries out designing and controlling based on a corresponding relation between finite impulse response digital filter group delay and a tap coefficient in a frequency response function. The tap coefficient of the filter FIR1 and the tap coefficient of the filter FIR2 in the FPGA are controlled so as to control the group delay of the filters to influence the signal channel group delay, thereby realizing simulation of a dispersion effect, generated at an ionosphere, of a broadband radio signal through air transmission. According to the invention, the provided simulator has advantages of simpleness, high reliability, and less consumed hardware resources; and signal feature prediction is not required. And the simulator adapts to signals with various systems.

Description

technical field [0001] The invention relates to an ionospheric dispersion effect simulator. Background technique [0002] Ionospheric dispersion is a phenomenon in which radio signals are distorted and pulse broadened in time and space after passing through the ionosphere. The ionization medium in the ionosphere will ionize the radio waves, which is called background ionization. The background ionization makes the refractive index of the ionosphere become frequency-dependent; in the ionosphere area, some gas molecules are ionized and released due to ultraviolet rays. The existence of free electrons and charged particles in the ionosphere slows down the propagation speed of radio signals; there are irregular electron density structures of various scales in the ionosphere, so that radio signals with different frequency components have different phase velocities when propagating in the ionosphere and phase relationship; ionospheric scintillation causes short-period irregular c...

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Problems solved by technology

[0003] The impact of dispersion effects on the characteristics and quality of radio signals needs to be evaluated in advance. Whether the performance indicators of broadband radio measurement and control systems, new system signals, especially broadband hop-spread signals are affected when they propagate through dispersive media, and to what extent, requires A set of simulators capable of simulating the dispersion effect is used for verification. At present, there is no shelf product that meets the above requirements on the market, which brings a lot of inconvenience to the development of measurement and control technology, especially the establishment and application of new measurement and control systems. Therefore, it is necessary to develop a set with The simulator for simulating the function of dispersion effect simulates a highly realistic space environment to verify system function indicators and test equipment status

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