6.1 Lab 6: analog-to-digital conversion, dtft and dft  (Page 2/4)

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Quantization

Now change the Number of quantization levels for some fixed values of Frequency and Sampling Frequency. As the number of quantization levels is increased, the Digital waveform becomes smoother and a smaller amount of quantization error or noise is generated.

Signal reconstruction

Next, set the frequency $f=\text{100}$ Hz and vary the sampling frequency. Observe the reconstructed waveform. [link] shows the reconstructed signals for three different values of skipped samples. If the sampling frequency is increased, fewer samples are skipped during the analog-to-digital conversion, which makes the reconstruction process more accurate.

Dtft and dft

In this example, let us compute and compare the DTFT and DFT of digital signals with the CTFT and FS of analog signals. [link] illustrates the completed block diagram of this transform comparison system. As discussed previously, to simulate an analog signal, consider a small time interval $\left(\text{dt}=0\text{.}\text{001}\right)$ . The corresponding discrete signal is considered to be the same signal with a larger time interval $\left(\text{dt}1=0\text{.}\text{01}\right)$ .

Generate a periodic square wave with the time period $T=0\text{.}1$ . Connect the input variable mode to an Enum Control to make the signal periodic or aperiodic. If the signal is periodic (case 0), compute the FS of the analog signal and the DFT of the digital signal using the fft function over one period of the signal. For aperiodic signals, only one period of the square wave is considered and the remaining portion is padded with zeros. For aperiodic signals, the transformations are CTFT (for analog signals) and DTFT (for digital signals), which are computed using the fft function. In fact, this function provides a computationally efficient implementation of the DFT transformation for periodic discrete-time signals. However, because simulated analog signals are actually discrete with a small time interval, this function is also used to compute the Fourier series for continuous-time signals. Because DFT requires periodicity, one needs to treat aperiodic signals as periodic with a period $T=\infty$ to apply this useful function. That is why the fft function is also used for aperiodic signals to compute CTFT and DTFT (as done in the earlier labs). However, in practice, it should be noted that the period of the zero padded signal is not infinite but assumed long enough to obtain a close approximation. Apply the same approach to the computation of CTFT and DTFT. Because DTFT is periodic in the frequency domain, for digital signals, repeat the frequency representation using the textual statement yd=repmat( yd,1,9) , noting that the fft function computes the transformation for one period only.

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
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
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
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
How can I make nanorobot?
Lily
how did you get the value of 2000N.What calculations are needed to arrive at it
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