Lecture #6 - Quantisation

Question 1

What is an ADC?

Answer 1

Physical device that converts voltage or current amplitude at the input into a binary code

Question 2

What is a quantised sample?

Answer 2

The quantised sample x̂[n] is the approximation of the ‘true’ sample x[n]

Question 3

What is the quantisation error?

Answer 3

e[n] = x̂[n] - x[n]

The quantised error minus the approximately ‘true’ error

Question 4

How does quantisation errors arise?

Answer 4

1. Quantisation noise - accumulates due to rounding and truncation.

Soln; Sufficiently small step size

2. Saturdation - input exceeds max or min value you can represent (clipping)

Soln; Plan for range