Signal
A signal is a physical quantity that can carry information.Signals can be described as:
| Property | Explanation |
|---|---|
| [see page 7, Continuous] | Energy is supplied indefinitely and resonance can be sustained (eg. flute). |
| Deterministic | Knowing how it's described, you can always reproduce the signal. |
| Deterministic Aperiodic | The signal doesn't repeat in a consistent way. |
| Deterministic [see page 8, Periodic] | The signal repeats at a fixed period. |
| Non-Deterministic | A function of a random variable which can't be predicted (think noise). |
| Stationary | |
| Analogue Signal | Infinite possible values, exist continuously in time. |
| Digital Signal | Quantised in amplitude and sampled in time frame. |
See some definitions of the features of a signal [see page 9, here] also note [see page 10, eulers formula] for the unit circle.
Note: the histogram of standard speech is a see page 19, super-gaussian distribution.