Transcript Key terms Sampling rate

Key terms
Sampling rate – how often we read the value of the signal
Resolution – the separation between “levels” for our samples
(can we read the value to the nearest 1V, or 0.1V)
Bits per sample – the number of bits (binary digits) we need to
record the value we measure.
Quantisation error – these are errors introduced when the
signal resolution is insufficient.
(e.g. signal value = 0.115V, we record 0.1V)
Key terms
Shannon-Nyquist theorem – states that the sampling rate must
be at least twice the highest frequency component in order to
accurately reproduce the signal.
Aliasing – spurious low frequencies not present in the original
signal, which are introduced when the sampling rate is too low
(think of the “wagon wheel effect”…!)
Starter question
A 30 second audio sample has a peak to peak voltage of 1.5V.
The signal is digitised, using 14 bits per sample and a
sampling rate of 40kHz.
1. How many levels does this give?
2. What will the voltage resolution of the signal be?
3. What is the time separation between samples?
4. What is the maximum frequency component that can be
accurately reproduced in the signal?
5. How much data is required to store one second of the signal?
6. How much data is required to store the entire signal?