The Modified Covariance method of spectral estimation, proposed as a
replacement of the conventional short term Fourier transform for use
with pulsed Doppler ultrasound blood flow detectors in order to improve
time/frequency resolution, is computationally far more demanding. The
use of an application specific architecture for real-time implementation
is of interest. A cost/benefit selection of systolic arrays, firstly
for a matrix solution method with suitable bus width and secondly for
calculation of covariance matrix elements, led to the choice of Cholesky
matrix decomposition, 12 bit bus width and a bi-linear systolic array
designed using a data dependence graph method.