# 0.2 Another way of viewing the world  (Page 2/2)

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From this type of observation, a whole slew of theory and algorithms have been developed to characterize such behavior. By taking the Fourier Transform of our sound file, we can see what frequencies make up the signal. Another way of thinking about it, the sound file can be decomposed as the sum of waves of differing frequencies, and the Fourier Transform provides a way of seeing the sound file in the time domain, as in Figures 2 and 3, to the frequency domain shown below in Figure 4.

The spectrogram shows us how the signal can be broken down into an infinite sum of waves with different frequencies. As Figure 4 shows, the most dominant frequency occurs at about 220Hz. This corresponds to the second harmonic of the signal. The fundamental frequency being 110Hz, which is correct, since the 'A' string of the guitar should be tuned to 110Hz. Apparently the guitar was in tune when the recording was made. Furthermore, you will also notice other dominant waves with frequencies of about 330Hz and 440Hz. Of the musicians out there reading this, this makes sense since 330Hz corresponds to an 'E' which would be the fifth of the 'A' and the third harmonic to the 'A' at 110Hz. But the take away message from these figures is that there are two ways of seeing the same phenomenon of the recorded sound file. One is to simply plot the resulting signal versus time. Another is to view the same signal and its spectrogram, or rather, what frequency components make up the sound file.

## Plucking the 'e' string of a guitar

Similar to plucking the guitar's 'A' string, here we provide the same graphs but for the sound file in Figure 5.

Let's point out some differences between Figures 2 and 6. Notice that in Figure 2, the signal decays to 0 a couple of seconds after the signal in Figure 6. Also notice that in Figure 7, the spacing between the oscillations of the signal is smaller than those in Figure 3.

Also, again notice that in Figure 7, the zoomed-in graph of the signal versus time, there are recurring patterns in the signal. See if you can convince yourself that the signal can be described as the sum of waves with differing frequencies.

Figure 8 shows the spectrogram of the sound file in Figure 5. The dominant peak occurs at 330Hz, which from our previous discussion is not surprising. The high 'E' string of a guitar should be tuned to 330Hz.

However, there are some differences to note between Figures 4 and 8. The spectrogram in Figure 8 has less prominent peaks. Between 200 and 300Hz, there seems to be a lump of frequencies that our sound wave has. One of the reasons the spectrum is not as "clean" as the one in Figure 4, is because the high E string causes the lower strings on the guitar to vibrate. Thus one sees lumps in the spectrogram below the fundamental frequency of 330Hz as well as the harmonics of the frequencies of the lower strings.

For more information on the algorithm/procedure that takes you to/from the frequency domain, Derivation of the Fourier Transform and The Fast Fourier Transform (FFT) are good mathematical sources.

how can chip be made from sand
is this allso about nanoscale material
Almas
are nano particles real
yeah
Joseph
Hello, if I study Physics teacher in bachelor, can I study Nanotechnology in master?
no can't
Lohitha
where is the latest information on a no technology how can I find it
William
currently
William
where we get a research paper on Nano chemistry....?
nanopartical of organic/inorganic / physical chemistry , pdf / thesis / review
Ali
what are the products of Nano chemistry?
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
learn
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
learn
da
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Bhagvanji
hey
Giriraj
Preparation and Applications of Nanomaterial for Drug Delivery
revolt
da
Application of nanotechnology in medicine
has a lot of application modern world
Kamaluddeen
yes
narayan
what is variations in raman spectra for nanomaterials
ya I also want to know the raman spectra
Bhagvanji
I only see partial conversation and what's the question here!
what about nanotechnology for water purification
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
Nasa has use it in the 60's, copper as water purification in the moon travel.
Alexandre
nanocopper obvius
Alexandre
what is the stm
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
what is Nano technology ?
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
how did you get the value of 2000N.What calculations are needed to arrive at it
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