Parallel hardware implementation of a 'pre-addition' matrix for the fi
rst step of a Fourier transform on n points where n is the product of
either two or three discrete primes is described. A set of adders with
a small amount of temporary memory is required; input and output is b
y a common bus. The individual microprograms for each processor are de
scribed. Detailed pipeline timings are given showing a nearly perfect
hardware utilization. The examples of 35 and 105 point transforms are
followed in detail.