1 TYPES OF SIGNALS AND ITS PROPERTIES Networks

1 TYPES OF SIGNALS AND ITS PROPERTIES Networks and Communication Department Net 352

Lecture Contents 2 Continuous-time and Discrete-time signals � Digital and Analog signals � Periodic � Even 11 -Jan-22 and Aperiodic signals and Odd signals Networks and Communication Department

3 Continuous and Discrete Signals Analog and Digital signals 11 -Jan-22 Networks and Communication Department

Continuous-time Signals: 4 A continuous-time signal is a signal that can be defined at every instant of time. A continuoustime signal contains values for all real numbers along the X-axis. It is denoted by x(t). Analog signals is a continuous-time signals. 11 -Jan-22 Networks and Communication Department

Discrete-time Signals: 5 Signals that can be defined at discrete instant of time is called discrete time signal. Basically discrete time signals can be obtained by sampling a continuous-time signal. It is denoted as x(n) Digital signals is a continuous-time signals. 11 -Jan-22 Networks and Communication Department

Analog and Digital Signals: 6 11 -Jan-22 Networks and Communication Department

Analog and Digital transmission: 7 Data : � entities Signals : � electric that convey information or electromagnetic representations of data Signaling : � physically propagates along a medium Transmission : � communication of data by propagation and processing of signals 11 -Jan-22 Networks and Communication Department

Analog and Digital data : 8 Analog Audio Video 11 -Jan-22 Digital Text and Numbers. � IRA (ASCII). Networks and Communication Department

Analog Signals : 9 Audio Signal s 11 -Jan-22 Frequency range of typical speech is 100 Hz-7 k. Hz Easily converted into electromagnetic signals Varying volume converted to varying voltage Can limit frequency range for voice channel to 300 -3400 Hz Networks and Communication Department

Analog Signals : 10 Audio Signal s 11 -Jan-22 Networks and Communication Department

Analog Signals : 11 Video Signal s 11 -Jan-22 To produce a video signal a TV camera is used USA standard is 483 lines per frame, at a rate of 30 complete frames per second Actual standard is 525 lines but 42 lost during vertical retrace Horizontal scanning frequency is 525 lines x 30 scans = 15750 lines per second Max frequency if line alternates black and white Max frequency of. Networks 4. 2 MHz and Communication Department

Analog Signals : 12 Video Signal s 11 -Jan-22 Networks and Communication Department

Analog signals : 13 11 -Jan-22 Networks and Communication Department

Digital Signals: 14 11 -Jan-22 Networks and Communication Department

Digital Signals : 15 Advantages cheaper less susceptible to noise interference 11 -Jan-22 Disadvantages suffer more from attenuation Networks and Communication Department

Digital Signals : 16 11 -Jan-22 Networks and Communication Department

17 Periodic and Aperiodic signals 11 -Jan-22 Networks and Communication Department

Periodic and Aperiodic signals 18 Periodic signals A signal is said to be periodic if it repeats itself after some amount of time x(t+T)=x(t), for some value of T. The period of the signal is the minimum value of time for which it exactly repeats itself. 11 -Jan-22 Aperiodic signals Signal which does not repeat itself after a certain period of time is called aperiodic signal. Networks and Communication Department

19 Periodic analog and digital signals 11 -Jan-22 Networks and Communication Department

20 Even and Odd signals 11 -Jan-22 Networks and Communication Department

Even and Odd signals: 21 Even An even signal is any signal 'x' such that x(t) = x(-t) Even signals are symmetric around vertical axis 11 -Jan-22 Odd an odd signal is a signal 'x' for which x(t) = -x(-t) Odd signals are symmetric about origin Networks and Communication Department

Summary 22 Types of Signals and its Properties: 11 -Jan-22 This module describes just some of the many ways in which signals can be classified. They can be continuous time or discrete time, analog or digital, periodic or aperiodic, odd or even. Networks and Communication Department

References 23 Types of Signals and its Properties: 11 -Jan-22 Data and Computer Communications, Ninth Edition by William Stallings, (c) Pearson Education - Prentice Hall, 2011 The Internet. Networks and Communication Department