Page 257 - DSP Integrated Circuits

242 Chapter 6 DSP Algorithms

needed. Such node values appear in only one of the subsequent expressions. We
get

In this algorithm, the only operation that is noncommutating with its adja-
cent operations is the quantization operation. Generally, the inputs to such opera-
tions must be computed explicitly, but in this case u% appears in only one
subsequent expression. Hence, 113 can be eliminated. We get the following expres-
sions that can be translated directly into a program:

A pseudo-Pascal program that implements the second-order section in direct
form II is shown in Box 6.3.

Box 6.3 Pseudo-Pascal program for emulation of a second-order section in direct form II
with two's-complement truncation and saturation arithmetic