An efficient use of DAC dynamic range in frequency-selective channel simulator

Development of new communication systems includes an experimental test-ing and debugging of preproduction models. Channel simulators are widely usedtools for testing systems in conditions which are very close to real-world radiochannel [1]. Today's level of technologies allows to develop fully digital channelsimulators, based, for example, on field programmable gate arrays (FPGA) [2].Common problem for the fixed point arithmetic devices is choosing scaleparameters. On the one hand we have to avoid overflow, but on the other handwe have to provide maximum ratio between signal and quantization noise. Thispaper presents the solution for the specified problem in case of hardware digi-tal multipath fading channel simulator design.This work was supported by the project №1060 within the government taskfor scientific research of the YarSU. The presented technique of parameter scal-ing for digital frequency-selective fading channel simulator provides maximallyefficient use of dynamic range of signal processing for a specified level of distor-tions of channel statistical characteristics. The feature of presented technique isthe division of scaling process into several stages, which provides minimal levelof distortions of channel characteristics due to simulator parameters trunca-tion. An effective use of DAC dynamic range of digital fading channel simulatorpermits to use external amplifiers with the lower gain to provide specified out-put signal power.