Comprehensive explanation of Aliasing?

  • Thread starter Thread starter Meriem
  • Start date Start date
  • Tags Tags
    Explanation
AI Thread Summary
Aliasing occurs when a continuous signal is digitized at a sampling rate lower than the Nyquist rate, resulting in distortion and jagged representations of smooth lines in signals like sound waves or images. The Nyquist theorem states that to accurately reconstruct a signal, it must be sampled at least twice the frequency of its highest component. When sampling below this rate, aliasing effects arise, leading to inaccuracies in the signal representation. To mitigate aliasing, a low pass filter can be applied before sampling, allowing for a more accurate capture of the signal by filtering out higher frequencies. Understanding these concepts is essential for effective signal processing and digital representation.
Meriem
Messages
8
Reaction score
0
Hello,

I need a comrehensive explanation of Aliasing? and its relation to filters...

Thanks for the answers
 
Engineering news on Phys.org
start with wikipedia...
 
http://en.wikipedia.org/wiki/Aliasing

Aliasing is what happens when you take a continuous signal and digitize it. It can only be approximated and as a result, smooth lines in a signal (whether they are a synthesized sound wave or a picture or some other signal is irrelevant) become jagged.
 
Aliasing is a form of distortion that happens when you sample a signal with a frequency less than the nyquist rate, the sampling theory simply states that if we take a number of samples of a signal at double the rate of it's highest frequency, the original signal can be reconstructed using these samples, so what happens when you sample at a rate lower than nyquist is that there will be an aliasing effect.

The aliasing effect could be removed by passing the signal through a low pass filter before sampling, thus we could calculate the band of the filter and multiply it by two and then sample at this rate.
 
Thanks a lot guys, I have already used wiki...Thanks again!

I will post my summary in the coming days so we all benifit from it!
 

Thread 'How might electronics be different if AC voltage was 72V at 45 Hz?'

Hey guys. I have a question related to electricity and alternating current. Say an alien fictional society developed electricity, and settled on a standard like 73V AC current at 46 Hz. How would appliances be designed, and what impact would the lower frequency and voltage have on transformers, wiring, TVs, computers, LEDs, motors, and heating, assuming the laws of physics and technology are the same as on Earth?
View full post »

Thread 'Why does the amperage go real high if there is a low voltage short?'

I used to be an HVAC technician. One time I had a service call in which there was no power to the thermostat. The thermostat did not have power because the fuse in the air handler was blown. The fuse in the air handler was blown because there was a low voltage short. The rubber coating on one of the thermostat wires was chewed off by a rodent. The exposed metal in the thermostat wire was touching the metal cabinet of the air handler. This was a low voltage short. This low voltage...
View full post »
Thread 'Electromagnet magnetic field issue'

Thread 'Electromagnet magnetic field issue'

Hi Guys We are a bunch a mechanical engineers trying to build a simple electromagnet. Our design is based on a very similar magnet. However, our version is about 10 times less magnetic and we are wondering why. Our coil has exactly same length, same number of layers and turns. What is possibly wrong? PIN and bracket are made of iron and are in electrical contact, exactly like the reference design. Any help will be appreciated. Thanks. edit: even same wire diameter and coil was wounded by a...
View full post »

Similar threads

Digital Electronics: Image Frequencies & Nyquist/Shannon Theorems
Replies
7
Views
4K
Is my understanding of the Nyquist theorem correct?
Replies
4
Views
2K
What is time domain aliasing in linear convolution?
Replies
2
Views
2K
How to Change Signal Bandwidth: Theoretical Possibilities and Effects Explained
Replies
1
Views
1K
Final Project (Matura Project) About The Wave Pendulum
Replies
2
Views
1K
Sampling a continuous-time signal, aliasing/Nyquist
Replies
1
Views
2K
Recommendation Needed for a Spectrum Analyzer
Replies
46
Views
3K
Nyquist sampling rate and signal anti-aliasing
Replies
8
Views
3K
Aliasing, Continuous sinusoids and discrete sinusoids....
Replies
3
Views
1K
What Is the Importance of the Nyquist Interval in Signal Processing?
Replies
10
Views
3K

Hot Threads

Recent Insights

Back
Top