Understanding the Effect of Uncorrelated Phase Noise on Multi-channel RF Vector Signal Generators and Analysers

Introduction With growth of applications such as beamforming, MIMO (multiple input multiple output) communications systems and even phase-array RADAR, the need for phase-coherent signal generation and acquisition systems is increasing. However, engineers still face challenges such as system size, cost and complexity. While you can use modular PXI instrumentation to solve many of the size and cost issues associated with phase coherency, calibrating MIMO systems is still a unique challenge. In figure 1, observe PXI system that has been configured for a 2x4 MIMO test application. As figure 1 illustrates, and as the block diagram in figure 2 illustrates, phase coherent measurement systems require each instrument to share a variety of timing and synchronisation signals.