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Analog and Discrete Waveforms with fs = 100 Hz and f = 10 Hz

Analog and Discrete Waveforms with fs = 100 Hz and f = 210 Hz


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.

Digital Waveform with Different Numbers of Quantization Levels: (a) 8, (b) 6, (c) 32

Signal reconstruction

Next, set the frequency f = 100 size 12{f="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.

Signal Reconstruction with Different Number of Samples Skipped in ADC: (a) 20, (b)10, (c) 5

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 ( dt = 0 . 001 ) size 12{ \( ital "dt"=0 "." "001" \) } {} . The corresponding discrete signal is considered to be the same signal with a larger time interval ( dt 1 = 0 . 01 ) size 12{ \( ital "dt"1=0 "." "01" \) } {} .

Block Diagram of a DTFT and DFT Transformation System

Generate a periodic square wave with the time period T = 0 . 1 size 12{T=0 "." 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 = size 12{T= infinity } {} 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.

Front Panel of a DTFT and DFT Transformation System: Aperiodic Signal

Questions & Answers

I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
scanning tunneling microscope
how nano science is used for hydrophobicity
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
what is differents between GO and RGO?
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
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
The nanotechnology is as new science, to scale nanometric
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
sciencedirect big data base
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
characteristics of micro business
for teaching engĺish at school how nano technology help us
How can I make nanorobot?
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, An interactive approach to signals and systems laboratory. OpenStax CNX. Sep 06, 2012 Download for free at http://cnx.org/content/col10667/1.14
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