Signals_lecture - 1 Digital Signal Processing in...

Info iconThis preview shows pages 1–10. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: 1 Digital Signal Processing in Communications Dr. Shu-hung LEUNG Office: G6509 Tel: 2788-7784 Email: EEEUGSHL@cityu.edu.hk 2 Information Textbook: An Introduction to Digital Signal Processing by Edmund M K Lai Assessment: Assignments (No marking) Quizzes: 3 (4 th , 8 th , 12 th week) 30% Examination 70% 3 Speech signals Speech signals are utterances in their acoustic form or electrical equivalent . Voiced speech such as vowels is a quasi- periodic signal (nearly periodic). 1 1 . 0 0 6 1 . 0 1 2 1 . 0 1 8 1 . 0 2 4 1 . 0 3- 0 . 3- 0 . 2- 0 . 1 0 . 1 0 . 2 0 . 3 0 . 4 T i m e i n s e c o n d Speech signal Signals 4 Classification of signals Analogue signal (IEEE standard dictionary) A signal that is solely dependent upon magnitude to express information content. Analogue signal is normally a function of continuous time. It is also called as continuous- time signal. Example: A speech signal is an analogue signal. The speech recorded in magnetic tape is an analogue signal. 5 Discrete-time signals A signal is defined only at discrete points in time with continuous or discrete amplitude. Example: (i) Monthly rainfall. (ii) Discrete-time sine wave with continuous amplitude. 5 1 0 1 5 2 0 2 5- 1- 0 . 8- 0 . 6- 0 . 4- 0 . 2 0 . 2 0 . 4 0 . 6 0 . 8 1 s a m p l e a m p litu d e Classification of signals x[n]={0, 0.4, 0.72, 0.93, 1, } 6 Digital signal A discrete-time signal has discrete amplitude. Example: (i) Yearly population . (ii) Digital sine wave with 11 levels. 5 1 0 1 5 2 0 2 5- 1- 0 . 8- 0 . 6- 0 . 4- 0 . 2 0 . 2 0 . 4 0 . 6 0 . 8 1 S a m p l e Am plitude Classification of signals 7 Advantages of Digital Signal Processing T here are numerous reasons for using digital signals. The reasons are: Advancement of digital technology and computer High speed and high precision analogue-to-digital converter (ADC) and digital-to-analogue converter (DAC). Low cost computing machine including personal computer (PC), microprocessor (P), micro controller (MCU), and digital signal processor (DSP). Low cost memory devices. 8 Stability: no drifting in component value with temperature or age. Reprogrammability: The processing of digital signal can easily be modified by programme. Precision: The precision of signals can be improved by increasing the bit dimension of the system. Easy to debug: Most of digital systems are provided with debugging tools to speed up development time. Advantages of Digital Signal Processing 9 Repeatability Analogue components such as resistor, capacitor and inductor generally cannot give exact value that causes performance variation for analogue systems....
View Full Document

Page1 / 37

Signals_lecture - 1 Digital Signal Processing in...

This preview shows document pages 1 - 10. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online