Abstract: An electromagnetic interference (EMI) shield fills an aperture in a wall of a system unit housing. The electromagnetic interference shield is integrally formed from sheet metal (e.g. stainless steel). It comprises a perforated substantially planar portion with fingers defined around the periphery thereof. A plurality of first fingers are preformed to define abutments to abut against an outer surface of the wall and a plurality of second fingers are preformed to define sprung latches for latching within the aperture. The combination of first and second fingers means that the EMI shield can be located in the aperture in a removable manner without the use of tools. The perforations are configured to permit ventilation of the interior system housing while preventing EMI interference radiating from the system housing. A handle portion is also formed at the periphery of the substantially planar portion for facilitating the insertion and removal of the shield.

Abstract: A method for performing Fast (forward or inverse) Fourier Transform in a micro-processor-based computer system. The microprocessor includes parallel execution resources for executing parallel floating-point addition, subtractions and multiplication operations on the contents of a specialized set of internal registers. The method comprises performing computations associated with two adjacent butterflies simultaneously and in parallel. Thus, data operands are accessed, and computational results are stored, from/to memory in pairs. Furthermore, the ordering and arrangement of program instructions is optimized with respect to the execution resources available in the microprocessor. Care is taken to avoid potential stalling conditions. A processor simulator is used to anticipate and avoid potential resource conflicts. For example, instructions which require a common execution resource may be separated with one or more intervening instructions which utilize different execution resources.

Abstract: Heat emitting electrical components are encased in a refrigerated package within a housing which may be under vacuum. Power for the components is supplied through a transformer within the vacuum housing, the secondary of which is in thermal contact with the package and has heat transmitting electrical connections to the components. To reduce conduction or convection of heat from the primary of the transformer to the refrigerated package, a small gap of about 1 mil is provided. For pot core transformers the core may be split, with the gap between the split portions. For toroidal transformers, the secondary is spaced from the primary as well as from the core by such gap.