Undersampling in digital signal processing

In signal processing, undersampling or bandpass sampling is a technique where one samples a bandpass-filtered signal at a sample rate below its Nyquist rate (twice the upper cutoff frequency), but is still able to reconstruct the signal.

1. What is undersampling and oversampling in digital signal processing?
2. What is undersampling in signals?
3. What is undersampling in image processing?
4. What effect is caused by under sampling?

What is undersampling and oversampling in digital signal processing?

Over-sampling implies having many more samples than the highest frequency of interest, and under-sampling implies we are down-converting the bandwidth of interest with a higher harmonic of the sampling clock (effectively).

What is undersampling in signals?

1.2 What is Undersampling? If we use the sampling frequency less than twice the maximum frequency component in the signal, then it is called undersampling. Undersampling is also known as band pass sampling, harmonic sampling or super-Nyquist sampling.

What is undersampling in image processing?

Undersampling has the effect of distorting image details, resulting in a phenomenon termed aliasing, which occurs when undersampled high spatial frequencies masquerade as (or "alias" to) lower spatial frequencies. There are several methods available for suppressing the effects of aliasing.

What effect is caused by under sampling?

If we take samples less than the twice of highest frequency component of the message signal (below the Nyquist rate), the problems arise that make perfect reconstruction impossible. This problem is known as aliasing.