Noise Concerns and Remedies in VXI and PXI Systems

For optimum performance, a modern, high performance, synthetic instrument must be designed to keep RF energy that is outside the module from leaking in-and not let any of its energy leak out into other modules. Every detail must be addressed. DC power lines, signal lines, air cooling holes, and conventional RF shielding are all important design considerations in the small confines of an SI chassis. Faster digital logic and amplifiers with excessively high gain-bandwidth products increase the design challenge of fielding a clean, high performance synthetic instrument. Each block of an Si-based system connects to another element or subsystem. Removing the mechanisms for spurs to propagate from one module to another is as important as removing the original source of the spur.