Adaptive Equalization Algorithm On Telemetry And Group Delay Multipath Channel

In recent years, with the improvement of telemetry communication rate and communication quality requirements, the group delay distortion caused by the non-ideal characteristics of the electronic device and the RF device can not be ignored. Meanwhile the complicated telemetry environment makes multipath channel exhibits frequency selectivity characteristics. These two factors can cause the received signal ISI, seriously affecting the quality of communication. Thus studying the technology for ISI and the telemetry channel which covers the group delay disortion and multipath effects has very important significance. The main contents of this paper and the work done include:For the issue of establishing telemetry channel model, the first major study of the factors and mechanisms leading to group delay. We use all-pass filter design method simulated group delay distortion channel model and analyze the linear and parabolic group delay distortion impact on signal transmission quality. Secondly, for telemetry communication radio channel multipath effects section and the time-varying characteristics, we use Rice and Rayleigh process simulation of multipath channel main path and sub-path channel. We established the telemetry multipath channel transmission model and compared the effects of frequency selective multipath effects on signal transmission. Finally, on the basis of group delay and multipath channel, we construct a complete telemetry channel model.For the ISI problem caused by telemetry channel group delay and multipath effects, we adopt adaptive equalization algorithms to eliminate the ISI problem. Simulation results show that:the linear distortion equalization algorithm can effectively influence on signal transmission group delay cancellation, general nonlinear equalization algorithm can also be effective multipath cancellation, but the two lower telemetry group delay multipath channel way ineffective. Aiming telemetry channel characteristics and actual demand, proposed a variable step size of decision feedback blind equalization algorithms. The proposed algorithm can effectively reduce the telemetry group delay multipath channel bit error rate, while this method avoids sending the training sequence, effectively improve the utilization of the channel.