Overview of Signals & Systems Hany Ferdinando Dept. of Electrical Engineering Petra Christian University

Overview of Signals and Systems - Hany Ferdinando General Overview It is an general introduction to signals and systems Examples of signals and systems Applications of signal and system theory Overview of Signals and Systems - Hany Ferdinando

Overview of Signals and Systems - Hany Ferdinando Introduction The concept of signals and systems arise in and extremely wide variety of fields They have important role in such diverse areas of science and technology Communication, aeronautics, circuit design, acoustics, seismology, biomedical, energy generation and distribution, chemical process control, speech processing, etc. Overview of Signals and Systems - Hany Ferdinando

Overview of Signals and Systems - Hany Ferdinando Communication Design of RF transceiver Modulation Choosing the suitable media for transmission Noise removal Echo cancellation Filtering Overview of Signals and Systems - Hany Ferdinando

Overview of Signals and Systems - Hany Ferdinando Circuit Design Block diagram concept Simulation and analysis Transient and steady state response Transformation Filter design Sampling Overview of Signals and Systems - Hany Ferdinando

Biomedical Engineering Signal processing of EEG and ECG Image processing in USG Noise removal Signal amplification Filtering Overview of Signals and Systems - Hany Ferdinando

Energy Generation & Distribution Active power filter High freq. in the power line signal Simulation and analysis Block diagram concept Overview of Signals and Systems - Hany Ferdinando

Overview of Signals and Systems - Hany Ferdinando Speech Processsing Noise removal Filtering Transformation Overview of Signals and Systems - Hany Ferdinando

Overview of Signals and Systems - Hany Ferdinando Definition A signal is a phenomenon, arising in some environment, that may be describe quantitatively Examples of signal are voltages and current in electrical circuit, audio signals, visual signals, sequence of bits from computers, RF signal from transmitter, ECG and EEG signal, Overview of Signals and Systems - Hany Ferdinando

Overview of Signals and Systems - Hany Ferdinando Definition A system is any part of environment that causes certain signals that exist in that environment to be related Examples of system are an electrical circuit (it relates voltage and current), a television (audio and visual signals), a country (national income, demography, etc.) Overview of Signals and Systems - Hany Ferdinando

Overview of Signals and Systems - Hany Ferdinando General Concept System output input System usually has input and output Such a system is called input-output system We do not require that the input determine the output uniquely Overview of Signals and Systems - Hany Ferdinando

This is input-output system Examples… Resistive electrical circuit system Consider a resistor element connected to a voltage source. We can assume that voltage is the input and current acts as output. But for some input voltage, there is no unique output current This is input-output system Overview of Signals and Systems - Hany Ferdinando

General Concept (cont.) If an input uniquely determines the output, it is called input-output mapping system Usually, signal is a function of time, such a signal is called time-signals Discrete-time signals Continuous-time signals Overview of Signals and Systems - Hany Ferdinando

This is input-output mapping system Examples… Parity Bit Generator A Parity bit generator always receives the digital input and gives the output uniquely for every input. It depends on the parity bit generator uses even- or odd-parity This is input-output mapping system Overview of Signals and Systems - Hany Ferdinando

This is discrete-time signals Examples… Dow-Jones averages It is a weighted average of the price of a selected portfolio of stocks traded in NYSE, which has been daily computed and recorded since 1897 This is discrete-time signals Overview of Signals and Systems - Hany Ferdinando

This is continuous-time signals Examples… The outdoor temperature The outdoor temperature at any given place taken as a continuous function of time. The physical world abounds with continuous-time signals This is continuous-time signals Overview of Signals and Systems - Hany Ferdinando

General Concept (cont.) There are two systems: Discrete-time systems (systems associated with discrete-time signals)  the time axis is finite and countable Continuous-time systems (system associated with continuous-time signals)  the time axis is infinite and uncountable Overview of Signals and Systems - Hany Ferdinando

App. to Signal Processing A typical problem in the area of signal processing is the removal of unwanted noise from a signal. Can you give examples? A model u = s + n is frequently used, where s is transmitted signal and n is noise added to the signal Overview of Signals and Systems - Hany Ferdinando

App. to Signal Processing The problem is how to design a filter as shown in figure below, whose function is to remove or at least attenuate the noise. Filter + signal s noise n received signal u = s + n filtered signal y Overview of Signals and Systems - Hany Ferdinando

App. to Communication Eng. Communication engineering deals with transferring information from one location to another. It uses high frequency waves as carrier. Modulator message s Modulated carrier (z) Demodulator y Overview of Signals and Systems - Hany Ferdinando

App. to Automatic Control Control engineering concerns itself with the design of automatic controller, whose purpose is to govern the dynamic behavior of a given system, e.g. automatic cruise control in a car Cruise Controller Car Car speed (v) Ref. speed (vr) Overview of Signals and Systems - Hany Ferdinando

App. to Power System Power Filter Controller Voltage and current with high frequency due to non linear load Controller Normal signal Overview of Signals and Systems - Hany Ferdinando

Overview of Signals and Systems - Hany Ferdinando Next… We have discussed the overview of signals and systems. This is important in giving a brief information about signal and system. Next, we will study an introduction to signal. You can read books: Signals and Systems by Alan V. Oppenheim, chapter 2, page 7-35 Overview of Signals and Systems - Hany Ferdinando