Environmental Engineering Reference
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of the operational amplifier are turned off, and only the noise source
of is activated. The output noise power of the integrator was com-
puted using both methods. Fig.11.34 gives the ratio of the CPU time
of the adjoint network method to that of the brute-force with various
step sizes used in computing and It is seen that the speedup
obtained using the frequency reversal theorem is significant. Also, the
speedup is step size dependent. It increases with the decrease in the step
size. These results are expected since the lack of efficiency of the brute-
force method is due to the repetitive calculation of at both the base
band and sideband frequencies. Also, the accuracy of the computation
of is inversely proportional to the step size whereas the computa-
tional cost is directly proportional to the step size. The deficiencies of
the brute-force method are eliminated once the frequency reversal the-
orem is employed. For every base band frequency, the adjoint network
is solved only once at the frequency. In other words, one calculation
of of the adjoint network per base band frequency is required. The
corresponding high-order frequency components are obtained using LU-
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