# 0.3 Lab 3 - frequency analysis  (Page 3/4)

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$x\left(t\right)=0+\sum _{\genfrac{}{}{0pt}{}{k=1}{k\phantom{\rule{0.166667em}{0ex}}\text{odd}}}^{13}\frac{4}{k\pi }sin\left(2\pi kt\right)\phantom{\rule{4pt}{0ex}}.$

These are the first 8 terms in the Fourier series of the periodic square wave shown in [link] .

Run the model by selecting Start under the Simulation menu. A graph will pop up that shows the synthesized square wave signaland its spectrum. This is the output of the Spectrum Analyzer . After the simulation runs for a while,the Spectrum Analyzer element will update the plot of the spectral energy and the incoming waveform.Notice that the energy is concentrated in peaks corresponding to the individual sine waves.Print the output of the Spectrum Analyzer .

You may have a closer look at the synthesized signal by double clicking on the Scope1 icon. You can also see a plot of all the individual sine wavesby double clicking on the Scope2 icon.

Synthesize the two periodic waveforms defined in the "Synthesis of Periodic Signals" section of the background exercises. Do this by setting the frequency, amplitude, and phaseof each sinewave generator to the proper values. For each case, print the output of the Spectrum Analyzer .

Hand in plots of the Spectrum Analyzer output for each of the three synthesized waveforms.For each case, comment on how the synthesized waveform differs from the desired signal, and on the structureof the spectral density.

## Modulation property

Double click the icon labeled Modulator to bring up a system as shown in [link] . This system modulates a triangular pulse signal with a sine wave.You can control the duration and duty cycle of the triangular envelope and the frequency of the modulating sine wave.The system also contains a spectrum analyzer which plots the modulated signal and its spectrum.

Generate the following signals by adjusting the Time values and Output values of the Repeating Sequence block and the Frequency of the Sine Wave . The Time values vector contains entries spanning one period of the repeating signal.The Output values vector contains the values of the repeating signal at the times specifiedin the Time values vector. Note that the Repeating Sequence block does NOT create a discrete time signal. It creates a continuous time signalby connecting the output values with line segments. Print the output of the Spectrum Analyzer for each signal.

1. Triangular pulse duration of 1 sec; period of 2 sec; modulating frequency of 10 Hz (initial settings of the experiment).
2. Triangular pulse duration of 1 sec; period of 2 sec; modulating frequency of 15 Hz.
3. Triangular pulse duration of 1 sec; period of 3 sec; modulating frequency of 10 Hz.
4. Triangular pulse duration of 1 sec; period of 6 sec; modulating frequency of 10 Hz.

Notice that the spectrum of the modulated signal consists of of a comb of impulses in the frequency domain,arranged around a center frequency.

Hand in plots of the output of the Spectrum Analyzer for each signal. Answer following questions:1) What effect does changing the modulating frequency have on the spectral density?2) Why does the spectrum have a comb structure and what is the spectral distance between impulses? Why?3) What would happen to the spectral density if the period of the triangle pulse were to increase toward infinity? (in the limit)

Is there any normative that regulates the use of silver nanoparticles?
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
why we need to study biomolecules, molecular biology in nanotechnology?
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
why?
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
anyone know any internet site where one can find nanotechnology papers?
research.net
kanaga
sciencedirect big data base
Ernesto
Introduction about quantum dots in nanotechnology
what does nano mean?
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
absolutely yes
Daniel
how to know photocatalytic properties of tio2 nanoparticles...what to do now
it is a goid question and i want to know the answer as well
Maciej
Abigail
for teaching engĺish at school how nano technology help us
Anassong
Do somebody tell me a best nano engineering book for beginners?
there is no specific books for beginners but there is book called principle of nanotechnology
NANO
what is fullerene does it is used to make bukky balls
are you nano engineer ?
s.
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
Tarell
what is the actual application of fullerenes nowadays?
Damian
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
Tarell
what is the Synthesis, properties,and applications of carbon nano chemistry
Mostly, they use nano carbon for electronics and for materials to be strengthened.
Virgil
is Bucky paper clear?
CYNTHIA
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
NANO
so some one know about replacing silicon atom with phosphorous in semiconductors device?
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Harper
Do you know which machine is used to that process?
s.
how to fabricate graphene ink ?
for screen printed electrodes ?
SUYASH
What is lattice structure?
of graphene you mean?
Ebrahim
or in general
Ebrahim
in general
s.
Graphene has a hexagonal structure
tahir
On having this app for quite a bit time, Haven't realised there's a chat room in it.
Cied
what is biological synthesis of nanoparticles
how did you get the value of 2000N.What calculations are needed to arrive at it
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