princomm presentation.pptx

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Introduction to Signals and

Systems:Deterministic andRandom Signals and their

Principles


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Signal

Any physical quantity that varies with time or some variables. A signal maybeconsidered to be a function of time that represents physical variable ofinterest associated with a system.

The term "signal" includes, among others, audio , video , speech, image ,communication, geophysical, sonar, radar, medical and musical signals
http://signalsworld.blogspot.com/2009/11/signal.htmlhttp://en.wikipedia.org/wiki/Audio_signalhttp://en.wikipedia.org/wiki/Videohttp://en.wikipedia.org/wiki/Imagehttp://en.wikipedia.org/wiki/Imagehttp://en.wikipedia.org/wiki/Videohttp://en.wikipedia.org/wiki/Audio_signalhttp://signalsworld.blogspot.com/2009/11/signal.html


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EXAMPLE OF SIGNALS

Speech Signal

Electrocardiogram ( ECG )

A signal that provides a doctor withinformation about the condition of thepatients heart.


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Electroencephalogram ( EEG)

A signal that provides information about

the activity of the brain

System

Is a combination and interconnection of several components to perform desiredtask. An integrated whole, even though composed of diverse, interacting

structure of subjunctions

-It is a physical device used to perform operations on an input signal. It alsoincludes the software realization of operations and processing techniques


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Analog

SIGNAL PROCESSING

Refers to manipulation, transformations and operations performed on input

signal to obtain output signal that has desired characteristics


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Digital


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Flexibility

Accuracy

Easily Stored

Sophisticated Signal

Processing algorithm

Cheaper (in some cases)

Advantages of Digital over Analog Signal Processing


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Classification of Signals

1. Multichannel and Multidimensional Signals

2. Continuous- Time vs. Discrete- Time Signals

3. Continuous Valued vs. Discrete-Valued Signals

4. Deterministic vs. Random Signals

Deterministic vs. Random Signals

Deterministic Signals

A special class of stationary signals, and they have a relatively constantfrequency and level content over a long time period. Deterministic signals are generatedby rotating machines, musical instruments, and electronic function generators. They arefurther divisible into periodic and quasi -periodic signals. Periodic signals have waveformswhose pattern repeats at equal increments of time, whereas quasi-periodic signals havewaveforms whose repetition rate varies over time, but still appears to the eye tobe periodic. Sometimes, rotating machines will produce quasi-periodic signals, especially

belt-driven equipment.


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Deterministic signals are probably the most important in vibration analysis andtheir spectra resemble the following:

Most quasi-periodic signalsare actually a combinationof several harmonic series.

Periodic signals always produce spectra with discrete frequency componentsthat are a harmonic series. The term "harmonic" comes from music, whereharmonics are multiples of the fundamental frequency.


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Random signals are random variables whichevolve, often with time (e.g. audio noise), but also withdistance (e.g. intensity in an image of a randomtexture), or sometimes another parameter.

They can be described as usual by their cdfand either their pmf (if the amplitude is discrete, as ina digitized signal) or their pdf (if the amplitude iscontinuous, as in most analogue signals).

However a very important additional property

is how rapidly a random signal fluctuates. Clearly aslowly varying signal such as the waves in an oceanis very different from a rapidly varying signal such asvibrations in a vehicle.

Random Signal


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END OF OURREPORT

THANK YOU FORLISTENING

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