RADIO COMMUNICATION CHANNEL WITH FREQUENCY MODULATED SIGNAL BASED ON PROGRAMMABLE LOGICAL INTEGRATED CIRCUIT

Abstract

This paper presents the results of an experimental study of a radio communication channel (RF) with a frequency-modulated signal based on a programmable logic integrated circuit (FPGA). The work highlights the features of hardware and software implementation of algorithms for the synthesis of frequency-modulated signal and demodulation of this signal using FPGA in real time. The software part is made in the development environment of ISE WebPack 14.7 in Verilog language with the ability to visualize the results of GTKWave. Hardware implementation is performed on the basis of FPGA (Spartan-6) using a debug board from Alinx AX309.
 The experimental study consists of two stages of the study of the FM oscillator modulator and the synchronous FM oscillator demodulator. In the course of research, the amplitude spectral characteristics of the signals (amplitude spectra) were obtained: at the output of the modulator and demodulator of the frequency-modulated signal, which have good agreement with the simulation results. The quality of the hardware synchronous demodulation of the FM signal based on the phase tuning system was confirmed by the result of the obtained spectrum of the restored information signal, in which the ratio between the first harmonic and the second is 51.87 dBm. When obtaining the results of experimental studies of the RH system, it was found necessary to take into account the peculiarities of the arithmetic of integers, which make errors in the hardware implementation of DSP algorithms.
 Thus, the use of programmable logic integrated circuits at the present stage of development of telecommunications and radio engineering opens wide opportunities for the construction of high-speed digital RH systems with parallel signal processing in real time.