Elementary CT Signalsfaculty.citadel.edu/potisuk/elec309/ppt/2018/ct_esig.pdf · 1 Elementary CT...

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1 Elementary CT Signals Prof. Siripong Potisuk CT Sinusoidal Signal Expressed with the sine or cosine function Three intrinsic parameters: A = amplitude = angular frequency (rad/s) ϕ = phase angle (rad) ) cos( ) ( ) sin( ) ( t A t v t A t i

Transcript of Elementary CT Signalsfaculty.citadel.edu/potisuk/elec309/ppt/2018/ct_esig.pdf · 1 Elementary CT...

Page 1: Elementary CT Signalsfaculty.citadel.edu/potisuk/elec309/ppt/2018/ct_esig.pdf · 1 Elementary CT Signals Prof. Siripong Potisuk CT Sinusoidal Signal Expressed with the sine or cosine

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Elementary CT Signals

Prof. Siripong Potisuk

CT Sinusoidal Signal

Expressed with the sine or cosine function

Three intrinsic parameters:

A = amplitude

= angular frequency (rad/s)

ϕ = phase angle (rad)

)cos()(

)sin()(

tAtv

tAti

Page 2: Elementary CT Signalsfaculty.citadel.edu/potisuk/elec309/ppt/2018/ct_esig.pdf · 1 Elementary CT Signals Prof. Siripong Potisuk CT Sinusoidal Signal Expressed with the sine or cosine

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Derived Parameters

Sinusoidal Metrics

Average or DC value of zero

A power signal with

RMS value =

Bounded between -A and A

2

2APavg

2

APavg

Page 3: Elementary CT Signalsfaculty.citadel.edu/potisuk/elec309/ppt/2018/ct_esig.pdf · 1 Elementary CT Signals Prof. Siripong Potisuk CT Sinusoidal Signal Expressed with the sine or cosine

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Example: Determine the parameters of the periodic

signal 1)3/8.0(cos2)(~ 2 ttw

Why Sinusoidal Function

Occur naturally : pendulum motion, bouncing

ball, string vibration, ocean surface ripples, etc.

Easy to handle mathematically

Easy to generate and transmit dominant

form of signal in the communications and power

industries

A set of harmonically related sinusoids is used

in Fourier series representation of well-defined

periodic signals

Page 4: Elementary CT Signalsfaculty.citadel.edu/potisuk/elec309/ppt/2018/ct_esig.pdf · 1 Elementary CT Signals Prof. Siripong Potisuk CT Sinusoidal Signal Expressed with the sine or cosine

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CT Real Exponential Signals

aBu(t)Betx at ,for )(

Page 5: Elementary CT Signalsfaculty.citadel.edu/potisuk/elec309/ppt/2018/ct_esig.pdf · 1 Elementary CT Signals Prof. Siripong Potisuk CT Sinusoidal Signal Expressed with the sine or cosine

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CT Complex Exponential Signals

Can be expressed analytically as

Periodic with a period of

Average Power:

)sin()cos(

)(~

00

00

tAjtA

eeAAetxtjjtj

0

20 T

2~ APx

CT Unit Impulse

Continuous-time impulse function

Also known Dirac Delta Function

Defined as a result of the limiting operation

on the width of a rectangular pulse while

keeping the unity area constant

constant area = strength

1)( and 0 ,0)( dtttt

Page 6: Elementary CT Signalsfaculty.citadel.edu/potisuk/elec309/ppt/2018/ct_esig.pdf · 1 Elementary CT Signals Prof. Siripong Potisuk CT Sinusoidal Signal Expressed with the sine or cosine

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)(lim)(

otherwise

2/2/

,0

,/1)(

0

tdt

ttd

Properties of CT Unit Impulse

. and at continuous is )(:

)( )()(:Sifting )4

)()()()(:Sampling)3

)()(:Even)2

)(||

1)(:scalingTime)1

00

00

000

btatttxNote

txdttttx

tttxtttx

tt

ta

at

a

b

Page 7: Elementary CT Signalsfaculty.citadel.edu/potisuk/elec309/ppt/2018/ct_esig.pdf · 1 Elementary CT Signals Prof. Siripong Potisuk CT Sinusoidal Signal Expressed with the sine or cosine

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Example: Evaluate the following integrals:

tdte

tdttt

t )22( (b)

)1()cos( (a) 2

Example: Graph the following signal:

)()(~0

n

nTttp

This is a periodic signal called an impulse train and

obtained by adding versions of the delta function

that are time-shifted by integer multiples of T0.

Page 8: Elementary CT Signalsfaculty.citadel.edu/potisuk/elec309/ppt/2018/ct_esig.pdf · 1 Elementary CT Signals Prof. Siripong Potisuk CT Sinusoidal Signal Expressed with the sine or cosine

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CT Unit Step Signal

A causal CT function defined by

A common test signal for feedback control system

and

0

0

,0

,1)(

t

ttu

dt

tdut

)()(

0

)()()( dtdtut

CT Unit Ramp Signal

A causal CT function defined by

A common test signal for feedback control system

0

0

,0

,1)(

t

ttr

t

tutdutr )()()(

Page 9: Elementary CT Signalsfaculty.citadel.edu/potisuk/elec309/ppt/2018/ct_esig.pdf · 1 Elementary CT Signals Prof. Siripong Potisuk CT Sinusoidal Signal Expressed with the sine or cosine

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Page 10: Elementary CT Signalsfaculty.citadel.edu/potisuk/elec309/ppt/2018/ct_esig.pdf · 1 Elementary CT Signals Prof. Siripong Potisuk CT Sinusoidal Signal Expressed with the sine or cosine

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CT Rectangular Pulse

A even CT function defined by

A common signal in communications system

21

21

2121

||

||

,0

,1)(rect

tutut

tt

General Rectangular Function

22

22

otherwise

)()(

,0

,1rect

TtuTtu

TtTTt

Page 11: Elementary CT Signalsfaculty.citadel.edu/potisuk/elec309/ppt/2018/ct_esig.pdf · 1 Elementary CT Signals Prof. Siripong Potisuk CT Sinusoidal Signal Expressed with the sine or cosine

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Waveform Synthesis

Page 12: Elementary CT Signalsfaculty.citadel.edu/potisuk/elec309/ppt/2018/ct_esig.pdf · 1 Elementary CT Signals Prof. Siripong Potisuk CT Sinusoidal Signal Expressed with the sine or cosine

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Example: Express the waveforms shown in terms of unit-

step and/or ramp functions.