N ATIONAL U NIVERSITY of S INGAPORE
DEPARTMENT OF ELECTRICAL & COMPUTER ENGINEERING
Course: EE2009  SIGNALS
EXPERIMENT S2 FREQUENCY MODULATION LABORATORY MANUAL
_
IMPORTANT!
READ THIS MANUAL C
Must the Nyquist rule be always obeyed?
The Nyquist rule is a simple one and is formulated for signal which is low pass in nature. Consider a signal with spectrum as shown below.
0 20 k
f
The signa
What is a D/A Converter?
A D/A or digital to analog converter is a device that converts a bit stream that represents a digital signal into an analog signal. Very simply, its function is the reverse to
What is an A/D Converter?
An A/D or analog to digital converter is a device that converts an analog signal into a bit stream that represents a digital signal. A common example is the A/D used in digit
What is the meaning of carrier in AM and FM?
The word "carrier" is used loosely in general to mean the use of a high frequency waveform or oscillator to shift the spectrum of a message signal to a hig
Will the answer to the spectrum be different be if we simply FT an impulse train rather than using FS?
F[ + ( t ) + ( t  3) + ( t  6 ) + ] = + 1 + e  j 3 + e  j 6 + It can be shown (not so ea
Is time expansion the same as dividing t and time shift the same as subtracting t?
There is no need and is in fact harmful to remember this type of things. The best or surest way is to look at or sket
Is it true that by simply replacing s with j , we will get Fourier transform from Laplace transform?
A simple answer is sometimes yes and sometimes no. The Laplace transform of xa ( t ) is X a ( s ) =
When we derived the FT from the FS, the spectrum becomes a function of f. But it was a function of k and f0. Is there a contradiction there?
Run the demonstration program. Does the spectral density at
Is there any mistake to the pole zero diagram in the Chapter on Digital Systems? Yes. There are some misprints on the size and shape of the unit circle and other symbols. The correct diagram is given
Why is it that we just need to have 3 sinusoids to represent a periodic digital signal with period 3?
Consider an analog periodic signal xa ( t ) with a period of, say, 4 seconds. To represent this an
N ATIONAL U NIVERSITY of S INGAPORE
DEPARTMENT OF ELECTRICAL & COMPUTER ENGINEERING
Course: EE2009  SIGNALS
EXPERIMENT S1 SIGNALS AND SPECTRA LABORATORY MANUAL
_
IMPORTANT!
READ THIS MANUAL C
Hints to Problem Set 5
1 (a) Sketch the power spectrum. You can do it component by component.
(b) Assume the triangles to be impulses recall what you see on the spectrum analyzer in laboratory S2. S
Hints to Problem Set 4
1 (a) Simplify the signal first when = 3 .
(b) Does the reddish component have a larger power? 2 (a) What is the impulse response? Is it likely that an extremely high voltage
Hints to Problem Set 3
1 (a) See if the signal is periodic. Try to write down its spectrum.
(b) Assume that the triangles seen on the spectrum analyzer correspond to actual impulses. See FAQ on power
Hints to Problem Set 2
1 (a) Recall the result from tutorial and laboratory experiment S1 that relates the spectrum of a single pulse to that when the pulse is made periodic. The book has a problem th
Hints to Problem Set 1
1 (a) Note that the signal is periodic. It is better to work out the spectrum of just 1 pulse and then use the results from tutorial and laboratory experiment S1. Note also that
Signal
x( t ) = F
1
Spectrum
{ X ( f )} =  X ( f ) e
jt
df
X ( f ) = F{ x( t )} = x( t ) e  jt dt

x1 ( t ) = real = [ x1 ( t ) ]
X 1 ( f ) = [ X 1 (  f )]
X 1 ( f ) = symmetric =
What is meant by the implementation complexity of a digital system?
In general, implementation complexity is the amount of hardware and software or standard operations that is needed to realize some s
Are the real Fourier series using sines and cosines equivalent to the complex Fourier series using complex sinusoids?
No. The complex Fourier series based on the complex sinusoid e jk0t can be regarde
How are loudspeakers, amplifier and equalizer used in an audio system?
A loudspeaker is a transducer that converts electrical into acoustic signals. Most loudspeakers work like a motor. However, inste
EE2009/EE2009E Signals / page 1
NATIONAL UNIVERSITY OF SINGAPORE
EXAMINATION FOR Semester I: 2005/2006
EE2009/EE2009E SIGNALS November/December 2005 Time Allowed: 2 Hours
INSTRUCTIONS TO CANDIDA
EE2009/EE2009E Signals / page 1
NATIONAL UNIVERSITY OF SINGAPORE
EXAMINATION
Semester II: 2004/2005
EE2009 SIGNALS April 2005 Time Allowed: 2 Hours
INSTRUCTIONS TO CANDIDATES: 1. This paper con
NATIONAL UNIVERSITY OF SINGAPORE
EXAMINATION FOR
Semester I: 2004/2005
EE2009/EE2009E SIGNALS November/December 2004 Time Allowed: 2 Hours
INSTRUCTIONS TO CANDIDATES: 1. This paper contains SIX
NATIONAL UNIVERSITY OF SINGAPORE
EXAMINATION FOR THE DEGREE OF
B.ENG. (ELECTRICAL) / B.ENG. (COMPUTER ENG.)
(Semester II: 2003/2004)
EE2009  SIGNALS
April 2004 Time Allowed: 2 Hours
INSTRUCTIO
NATIONAL UNIVERSITY OF SINGAPORE
EXAMINATION FOR THE DEGREE OF
B.ENG. (ELECTRICAL) / B.ENG. (COMPUTER ENG.) / B.TECH. (ELECTRONICS)
(Semester I: 2003/2004)
EE2009/EE2009E  SIGNALS
November 2003
NATIONAL UNIVERSITY OF SINGAPORE
EXAMINATION FOR THE DEGREE OF
B.ENG. (ELECTRICAL) / B.ENG. (COMPUTER ENG.)
(Semester II: 2002/2003)
EE2009  SIGNALS
May 2003 Time Allowed: 2 Hours
INSTRUCTIONS
NATIONAL UNIVERSITY OF SINGAPORE
EXAMINATION FOR THE DEGREE OF
B.ENG. (ELECTRICAL) / B.ENG. (COMPUTER ENG.)
(Semester II: 2002/2003)
EE2009  SIGNALS
May 2003 Time Allowed: 2 Hours
INSTRUCTIONS
NATIONAL UNIVERSITY OF SINGAPORE
EXAMINATION FOR THE DEGREE OF
B.ENG. (ELECTRICAL) / B.ENG. (COMPUTER ENG.) / B.TECH. (ELECTRONICS)
(Semester I: 2002/2003)
EE2009/TE2009  SIGNALS
November 2002 
EE2009/EE2009E Signals / page 1
NATIONAL UNIVERSITY OF SINGAPORE
EXAMINATION FOR
(Semester I: 2006/2007)
EE2009/EE2009E SIGNALS November 2006 Time Allowed: 2 Hours
INSTRUCTIONS TO CANDIDATES: 1