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Digital Signal Processing

with DSK6713

Lab Instructor

Waseem Khan

Department of Electrical Engineering

Air University

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Objective The objective of these exercises is to make you

learn how to implement DSP algorithms on a

DSP kit.

DSP kit available to us is based on TIs DSP

TMS320C6713.

These exercises will be aimed at exploring DSP

kit and its allied tools as much as possible.

Before lab exercises on DSK we will refresh ourminds with Matlab and discuss the how to

convert a Matlab code into a DSP program.

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Pre-requisite Signals and Systems

C Language (Skill level : medium) Matlab (Skill level : Beginner)

To have a quick refresher of Matlab you cancopy tutorial from share folder

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What we will not do?

We will not implement a complete project

such as a modem, speech processor, etc. We will also not discuss theoretical details of

signal processing such as convolution,filtering, Fourier transform, etc.

We will also not deal with C language issues

in lab sessions. We can discuss such issues outside the

class.

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Todays Agenda

Introduction to Digital Signal Processor

Why we need a DSP?

Comparison of DSPs with general-purpose

processors

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What is a DSP?

As the name suggests, it is a processor specially

designed for processing of a digitized signal.

A simple digital processing system

DSP

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Why DSP? Cant we process a digital signal using a microcontroller

or a general purpose processor such as Pentium?

In general, processors perform operations in two major

categories i.e. data manipulation, (e.g. word processing

and database management), and mathematical

calculation (e.g. digital signal processing).

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Why DSP? All processors can perform both tasks. But it is difficult

(expensive) to make a device, optimized for both. There

are technical tradeoffs in the hardware design, such asthe size of the instruction set and how interrupts are

handled.

DSPs are specially designed to perform themathematical calculations needed in Digital Signal

Processing.

General-purpose processors are usually not employed inreal-time systems, while DSPs are largely employed in

real-time systems.

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Real Time System A real-time system is one that must process information

and produce a response within a specified time, else risksevere consequences, including failure. That is, in a

system with a real-time constraint it is no good to have

the correct action or the correct answer aftera certain

deadline: it is either by the deadline or it is useless.

A real-time system is one whose correctness is based

on both the correctness of the outputs and their

timeliness. The noveltyhere is that the system is time

critical.

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A Simple DSP Problem

Most of the time, a DSP is busy in MAC (multiply-

accumulate) operations.

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A Simple DSP Problem A general-purpose processor which is not optimized for

such operations, take many cycles to complete a MAC

operation. A DSP having hardware

multiply-accumulator can

execute a MAC operation in asingle cycle.

A C6700 DSP has two

separate hardware MACs and

therefore can perform two MAC

operations in a single cycle.

Isnt it marvelous?

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A Simple Matlab Problem Write a function fact() in Matlab that will take an

integer as input and calculates its factorial. Thefunction will be callable from command windowin the following format.

fact (num)

num is the integer input to the function.

You are not allowed to use built-in function of

Matlab to calculate factorial.