In the theories of
modulation
In electronics and telecommunications, modulation is the process of varying one or more properties of a periodic waveform, called the ''carrier signal'', with a separate signal called the ''modulation signal'' that typically contains informatio ...
and of
stochastic process
In probability theory and related fields, a stochastic () or random process is a mathematical object usually defined as a family of random variables. Stochastic processes are widely used as mathematical models of systems and phenomena that appea ...
es, random modulation is the creation of a new signal from two other signals by the process of
quadrature amplitude modulation. In particular, the two signals are considered as being
random processes. For applications, the two original signals need have a limited frequency range, and these are used to modulate a third sinusoidal
carrier signal whose frequency is above the range of frequencies contained in the original signals.
Details
The random modulation procedure starts with two stochastic
baseband signals,
and
, whose
frequency spectrum is non-zero only for