Abstract: A method for performing electrical acceptance tests on a sub-system including a test substrate, a microprocessor and one or more associated computer components, such as SRAM, DRAM and ROM. A pin grid array, ball grid array, line grid array or equivalent test connector system is provided that allows direct addressing of selected circuits of the microprocessor and of each associated component. The microprocessor plus substrate are first tested together. If this test is successful, the associated components are then added, preferably one at a time, and the new sub-system is tested. If a particular sub-system fails a test, the cause(s) of failure can be isolated and removed, where possible, and the modified sub-system can be retested.

Abstract: A digital array signal processor and an associated method are described for implementing the fast Fourier transform radix-4 butterfly algorithm. The digital array signal processor is an integrated circuit with a four stage pipeline and can perform a radix-4 butterfly operation on four complex operands every 80 nanoseconds. Using the decimation-in-frequency implementation of the radix-4 butterfly algorithm, the digital array signal processor includes a first stage for distribution of complex input operand values, a second stage for performing addition and subtraction operations, a third stage for performing multiplication operations and a fourth stage for distribution of the output operand values. The digital array signal processor can be reconfigured to perform a radix-2 butterfly operation on two sets of two complex numbers during the 80 nanosecond machine cycle as well as frequently used arithmetic and logic operations.