US Patent 7809404 MIMO passive channel emulator

Embodiments of methods and means for passively emulating channels in a multiple-input multiple output (MIMO) system are provided. Such embodiments include passively splitting a plurality of radio frequency signals into a greater plurality of such signals. Each of the greater plurality of radio frequency signals can then be selectively and passively attenuated, delayed and/or phase shifted. The resulting modified radio frequency signals are then recombined crossed over channels and coupled to a plurality of output nodes. Economical and versatile device and system testing is thus facilitated in a low-noise radio frequency environment without the need for complex up/down frequency or analog/digital conversions.