Some Basic Cencept Of Analog Communication

03-02-2009 Tuesday, February 03, 2009 7:16 AM

ANALOG COMMUNICATION Signal---Signals are the mathematical function that always convey a certain message TYPES OF SIGNALS 1.Multichannel signal---actually they are the combination of signals originate from different sources

Here s1,s2,s3 are three different sources and x1(t),x2(t),x3(t) are the signal functions respectively

2.Multidimensional signals--They are the signals which can be represented in more than on dimension like all the analog signals or waveforms are one dimensional while radio waves are 2-dimensional 3.Deterministic signals--These are those type of signals that have no value of un-certainty or have high Certainty within a period of time. Like square wave

4.Non-deterministic or Random signals--They are just opposite of random signals. A random signal is shown below

analog communication Page 1

The output 0f the signal cannot be define at any instant

5.Analog signal---They are the continuous with time signal and have certain value with Time.

6.Digital signal---Those signals which have discrete values of time. Digital signals are basically binary Signals and used to represent certain amount of voltage signal.

analog communication Page 2

Signals and used to represent certain amount of voltage signal.

Discrete signals have different amplitude at different time 7.Periodic and Non-periodic signals--Those signals that follows the equation x(t+T)=x(t) are called periodic signals and which do not follow the given equation are called Non-periodic signal. Here T is the fundamental time period of signal T=2∏/ω 8.Energy signals---Those signals that have finite value of energy and zero average power are known as Energy signals. Condition to determine energy signals ----Its very easy to determine an energy signal If t→∞ ,then if x(t)=0 Where x(t) is the amplitude of the signal

analog communication Page 3

Where x(t) is the amplitude of the signal Then it is a energy signal The equation for energy signal is given by ∞ E(t)=∫[x(t).x(t)]dt -∞ All non periodic signals are energy signals

9.Power signals--Those signals which have infinite energy but have finite power are called power signals. Condition to determine power signals---If t→∞ ,then if x(t)≠0 Then it is a power signal The equation for power signal is given by we have P=V.V/R take R=1 therefore P=V.V=x(t).x(t) ∞ therefore P(t)=∫[x(t).x(t)]dt lim - ∞ T→∞

analog communication Page 4