Realisation of Digital Filters - Digital Signal Processing: A Practitioner's Approach - page 102

Figure 5.1 General block schematic for a DSP realisation

5.2 Development Process
The development process is depicted in Figure 5.2. There are nine distinct phases in
the development process. These phases have remained the same throughout.
Understanding the user application constitutes phase 1, based on which a specifica-
tion document is generated in phase 2. This goes back and forth between the
designer and the user, and finally a well-understood document is generated. In phase
3 a detailed design document is produced, which includes as many aspects of the
problem as possible, including the development methodology. From 1975 to 1985,
on completing phase 3 it was the general practice to go ahead with the coding and
run the programs on the hardware by committing them to an EPROM or by testing
them on local RAMs.

1

User App

6

Embed

2

SRS Doc

9

4 8

3

7

Design Code

Test Vectors Dif

5

MATLAB

Figure 5.2 How to implement DSP algorithms

The test cycles (moving back and forth between phases 4 and 6) are extremely
time-consuming; any errors in the design require an elaborate process of retracing.
Phases 3, 4, 6, 8 and 9 are quite often moved back and forth till the desired goal is
achieved. From 1985 to 1995, another path entered the industrial process, one that
used to be the domain of the universities. This path has a new phase, phase 5. It is a
combination of phases 4 and 6, without hardware but close to reality. Most of the