Varying signal strength with information.

Maximum height of a wave.

Height of a pulse signal.

In quantum physics, the scattering amplitude is the probability amplitude of the outgoing spherical wave relative to the incoming plane wave in a stationary-state scattering process.

Varies signal strength to encode information.

(quantum mechanics) A complex number which is the coefficient of a component of a quantum state and whose product with its own complex conjugate gives the probability that the state will collapse to that component (when measured). (Note: the quantum state being thought of as a linear combination of its components.)

Variation in signal strength frequency.