Upsampling and aliasing

1. Does upsampling cause aliasing?
2. What is the difference between upsampling and oversampling?
3. What is difference between upsampling & interpolation?
4. Does downsampling cause aliasing?

Does upsampling cause aliasing?

It means creation of frequency components above 1/2 sampling rate of the original signal. Sometimes it is also considered to be a form of aliasing. When you are upsampling by a non-integer ratio (e.g. from 44.1 to 96 kHz), you get both imaging above 1/2 sampling rate of the original signal and aliasing below that rate.

What is the difference between upsampling and oversampling?

Basics of Sampling - Oversampling and Upsampling

When practically implemented though, oversampling refers to using a higher sampling rate than needed to run the A/D or D/A converter thus increasing the rate of the signal. Upsampling is on the other hand a rate conversion from one rate to another arbitrary rate.

What is difference between upsampling & interpolation?

Upsampling adds to the original signal undesired spectral images which are centered on multiples of the original sampling rate. “Interpolation”, in the DSP sense, is the process of upsampling followed by filtering. (The filtering removes the undesired spectral images.)

Does downsampling cause aliasing?

If a discrete-time signal's baseband spectral support is not limited to an interval of width 2 π / M radians, downsampling by M results in aliasing. Aliasing is the distortion that occurs when overlapping copies of the signal's spectrum are added together.