Howtosignalprocessing
- How do you reconstruct a signal from its samples?
- What is the minimum sample frequency needed to reconstruct an analog signal?
- What happens if sampling is below the Nyquist rate?
- What is aliasing effect and how do you avoid it?
How do you reconstruct a signal from its samples?
The reconstruction process consists of replacing each sample by a sinc function, centered at the time of the sample and scaled by the sample value x(nT) times 2fc/ fs and adding all the functions so created. Suppose the signal is sampled at exactly Nyquist rate fs= 2fm, Then fm= fs/2 = fs- fm and Fm= 1/2 = 1- Fm.
What is the minimum sample frequency needed to reconstruct an analog signal?
The Sampling Theorem states that a signal can be exactly reproduced if it is sampled at a frequency F, where F is greater than twice the maximum frequency in the signal. The sampling rate for an analog signal must be at least two times as high as the highest frequency in the analog signal in order to avoid aliasing.
What happens if sampling is below the Nyquist rate?
When the sampling frequency drops below the Nyquist rate, the frequencies will crossover and cause aliasing.
What is aliasing effect and how do you avoid it?
Aliasing is the effect of new frequencies appearing in the sampled signal after reconstruction, that were not present in the original signal. It is caused by too low sample rate for sampling a particular signal or too high frequencies present in the signal for a particular sample rate.
