How to describe correlated noise after the signal is oversampled?

1. What happens when the sampling frequency is too high?
2. What happens when a signal is oversampled?
3. Does oversampling increase noise?
4. What will happen if we oversample or undersample an analog signal while transmitting to digital signal?

What happens when the sampling frequency is too high?

If the rate of samples is too high the system may not be able to process them fast enough - it runs out of processing time.

What happens when a signal is oversampled?

Oversampling increases the density of samples, with the hope that some of the (newly calculated) additional samples will be near the peaks of the signal. These additional sample values can be used to make an improved estimate of the peak signal level.

Does oversampling increase noise?

Oversampling Description

As a general guideline, oversampling the ADC by a factor of four provides one additional bit of resolution, or a 6 dB increase in dynamic range. Increasing the oversampling ratio (OSR) results in overall reduced noise and the DR improvement due to oversampling is ΔDR = 10log10 (OSR) in dB.

What will happen if we oversample or undersample an analog signal while transmitting to digital signal?

Oversampling unnecessarily increases the ADC output data rate and creates setup and hold-time issues, increases power consumption, increases ADC cost and also FPGA cost, as it has to capture high speed data.