The unit signals

In describing the relation between systems and signals, the three unit signals play an important role:

1. Unit pulse: if k=0, else 0
2. Unit step: if else 0
3. Unit ramp: if else 0
4. Unit sinusoid:

The term `unit' in this context means that the amplitude and frequency values taoke on a notional value of 1. The unit pulse defines the `impulse response' of a system, particularly a filter.