Quantized Filter Analysis - Introduction to Digital Signal Processing and Filter Design - page 379

input samples are represented by a finite number of bits. We have also considered
the effect of rounding or truncating the results of adding signals or multiplying
the signal value and the coefficient of the filter and ascertained that there is no
possibility of limit cycles or unstable operation in the filter. Very often a digital
filter is used as a prominent part of a digital system like a cell phone, which has
other components besides power supply, keyboard, or other I/O interfaces. So
we have to simulate the performance of the whole system with all components
connected together in the form of a block diagram.
7.7 SUMMARY
In this chapter we described the use of the MATLAB tool, called the fdatool ,
to design digital filters with finite wordlength for the coefficients in fixed-point
and floating-point representations, and investigated several different types of fil-
ter structures and different types of magnitude response specifications. Once we
narrowed down the choice of the filter that meets the frequency response spec-
ifications, we have to simulate the performance of the filter using Simulink, to
check that the filter works satisfactorily under different types of input signals
that will be applied in practice. In Chapter 8 we discuss this and other practical
considerations that are necessary for hardware design of the filter or the whole
digital system in which the filter is embedded.
PROBLEMS
The problems given in Chapter 4 can be assigned either as homework or as
a term project only if the FDA Toolbox is available with MATLAB and Signal
Processing Toolbox in the computer facilities of the school, college, or university.
The students may be asked to investigate the quantization effect of the filters
specified in Chapter 4 and arrive at the suboptimal choice, using these tools.
REFERENCES
1. S. K. Mitra, Digital Signal Processing—A Computer Aided Approach , McGraw-Hill,
1998.
2. E. C. Ifeachor and B. W. Jervis, Digital Signal Processing, A Practical Approach ,
Prentice-Hall, 2002.
3. A. Bateman and I. Paterson-Stephens, The DSP Handbook, Algorithms, Applications
and Design Techniques , Prentice-Hall, 2002.
4. S. K. Mitra and J. F. Kaiser, eds., Handbook of Digital Signal Processing , Wiley-
Interscience, 1993.
5. S. M. Kuo and B. H. Lee, Real-Time Digital Signal Processing: Implementations,
Applications and Experiments with TMS320C55X , Wiley, 2001.