TAE-1Subject:

Self Study

“Activity Based Learning”Topic

“Microprocessor Based Digital Filter”

Teacher Assessment Exam-1

Department Of Electronics and Tele-Communication Engineering

(2015-2016)

3rd Year | 5th Semester ©Subject- Self Study

“Activity Based Learning”To p i c :

“Microprocessor Based Digital Filter”

S u b m i t t e d B y :

Ashish Pandey (30)

G u i d e d B y :Prof. Kamlesh Kalbande,

Ass. Proff, E&TC Department,G.H.R.C.E., Nagpur.

Introduction to Digital Filter

• Digital filter is a system that performs mathematical operations on a sampled, discrete-time signal to reduce or enhance certain aspects of that signal.

• Digital filters are used for two general purposes:

(1) Separation of signals that have been combined.

(2) Restoration of signals that have been distorted in some way.

Introduction to Microprocessor

• A microprocessor is an electronic component that is used by a computer to do its work.

• It is a central processing unit on a single integrated circuit chip containing millions of very small components including transistors, resistors, and diodes that work together.

• Microprocessors help to do everything from writing to searching the Web.

• Everything a computer does is described by lots of precise instructions, and microprocessors carry out these instructions at incredible speed—many millions of times a second.

Abstract

• The relation between the performance of digital filters and some inherent characteristics of the latest microprocessors.

• The implementation of digital filters on microprocessor(s) offers some advantages, but at the same time imposes limits on the speed, accuracy or even stability of digital filters.

• Parallel processing technique implemented on multi—microprocessor structures is considered as an alternative to significantly improve the filter performances.

Objectives

• The objective is to investigate the design and to carry out the actual implementation of microprocessor-based Digital filters which may be suitable for various identification purposes.

• The procedure is based on bilinear transformation technique with emphasized consideration on the compensation of frequency and on the choice of the ratio of working frequency to sampling frequency.

• The effectiveness of the proposed design procedure will be demonstrated by several examples.

• It is remarked that the potential of the procedure may be enhanced by microprocessor based digital filter design techniques.

Goals to Design Microprocessor Based Digital Filter

• The main goal of the paper is to find a methodology to study the implementation of digital filters on microprocessors.

Microprocessors characteristics

• The most important factors which influence the microprocessor performances are the technology and the hardware architecture and the instruction set.

• The technology is the basic factor which imposes limitation on speed, packing density and power consumption.

• Microprocessor architecture has evolved from single core processors to multi-core processors. Processors with two or more cores are faster because they can process multiple pieces of information simultaneously.

• The instruction set contains logic operations, data transfers, program control instructions.

• The First Generation Microprocessor.• The Second Generation Microprocessor.• The Third Generation Microprocessor.

Microprocessors characteristics

First generation Microprocessor for Digital Filter

It is among which employed the p—channel MOS technology. (Intel 8008)We ignore this processors because of low performances when compared with other newer processors.

It is among which employed the n—channel MOS processor. (Intel 8080,Motorola 6800, F—8, Zilog Z—80, etc. )

This is 8 bit data bus and address directly up to 64 K bytes of memory.

This made possible the utilization of only one +5 V power supply and the increase of processing speed.

Second generation Microprocessor for Digital Filter

• It is called as 16—bit microprocessors (Intel 8080, 8086, 8087) which use H—MOS and have improved architectures and enhanced instruction sets.

• It can perform in hardware operations such as multiply, add, divide, square root, tangent and exponentiation.

• The clock speed was considered to be 2 MHZ for 8080 and 5 MHZ for 8086 and 8087.

• In addition to increasing the clock speed up to 8 MHZ, pipeline architecture was used.

Third generation Microprocessor for Digital Filter

DESIGN OF DIGITAL FILTERS

• The basic steps in the design of digital filters generally involve:

• The specification on the general characteristics of the filters.

• The approximation and design consideration in attaining the specification.

• The realization of the filters using finite precision arithmetic.

ERROR ANALYSIS

• When signals are represented by numbers inside the processor, a quantization effect takes place.

• In recursive filters, this effect is removed and amplified by the closed loops.

• Nonlinearities such as quantization noise, limit cycles and overflow are therefore introduced.

• When signals are represented on microprocessors with fixed point arithmetic we have the choice to use integers or numbers between —1 and +1.

• An expression is derived for the power of the round—off (RO) noise at the output of a filter is based on statistical arguments. The variance of the noise error is given by:

Working Diagram

RELATIONSHIP BETWEEN THE PERFORNANCES OF DIGITAL FILTERS AND

MICROPROCESSOR CHARACTERISTICS

N1

8086 — Single precision

Computational Time and Error Vs. Filter Order

Filter Order

8086 — Double precision

Computational Time and Error Vs. Filter Order

RELATIONSHIP BETWEEN THE PERFORNANCES OF DIGITAL FILTERS AND

MICROPROCESSOR CHARACTERISTICS

Conclusion

• It is reminded that the microprocessor-based filters can readily be tuned, by adjusting the sampling frequency w , so that the critical frequencies coincide with the desired specifications

REFERENCES

• A. V. Oppenheim and R. W. Schafer, "Digital Signal Processing," Prentice—Hall, Inc., Englewood Cliffs, New Jersey, 1975.

• L. Altman, editor, "Microprocessors,“ Electronics Book Series, McGraw—Hill Co., New York, 1975.

• ieeexplore.ieee.org