Why upsampling contracts the spectrum?

1. What is the purpose of upsampling?
2. Why do we Upsample a signal?
3. What is the effect of upsampling in the frequency domain?
4. What are the advantages of upsampling?

What is the purpose of upsampling?

The purpose of Upsampling is to manipulate a signal in order to artificially increase the sampling rate.

Why do we Upsample a signal?

The purpose of upsampling is to add samples to a signal, whilst maintaining its length with respect to time. Consider again a time signal of 10 seconds length with a sample rate of 1024Hz or samples per second that will have 10 x 1024 or 10240 samples.

What is the effect of upsampling in the frequency domain?

Upsampling adds to the original signal undesired spectral images which are centered on multiples of the original sampling rate. In Frequency domain , Upsampling means the padding of zeros at the last of max frequency components on all sides of the signal.

What are the advantages of upsampling?

Converting a digital (sampled) signal to a continuous analogue waveform requires interpolation to produce the values between sample points. Doing part of this interpolation digitally (upsampling) simplifies the analogue circuitry and gives better results. That's all there is to it.