Abstract

In the Tracking and Data Relay Satellite System (TDRSS), the 30-filter banks on the earth station, which are used to separate the radio-frequency (RF) bandpass signal, are designed with sharp transition band, resulting in large group delay. The group delay characteristic in a single channel is always not so flat at pass band. Moreover, the group delay characteristics among multiple channels are uncorrelated with each other. Thus, the observed 30-element signals are distorted and inconsistent in phase and amplitude, which result in the degradation of the Digital Beamforming (DBF) performance. According to this problem, a mathematical model is firstly introduced in to explore the derivation about the effects on DBF performance due to the inter-channel group delay. To eliminate the effectiveness, this paper put forward using adaptive equalization technique such as LMS. Finally the process of the equalizing is simulated in MATLAB/SIMULINK. The results show that adaptive equalization technique can compensate the influence effectively.

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