The Modulation sphere or M-space formulation is a scheme or
theory representing the system of effects of
phase modulation and
amplitude modulation
Amplitude modulation (AM) is a modulation technique used in electronic communication, most commonly for transmitting messages with a radio wave. In amplitude modulation, the amplitude (signal strength) of the wave is varied in proportion to ...
as applied together on a
carrier wave. The relations between both modulations on the carrier are also accounted for.
The modulation sphere representation relates three variables in three space, M1, M2 and M3:
*The M1 axis defines which
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 ...
type (AM or PM) dominates over the other at a set time instance on the carrier and at which degree.
*The M2 axis defines if the interaction between the two modulations is correlative, or anti-correlative (''see
Correlation
In statistics, correlation or dependence is any statistical relationship, whether causal or not, between two random variables or bivariate data. Although in the broadest sense, "correlation" may indicate any type of association, in statistics ...
'') in phase, and at which degree, at the same instance.
*The M3 axis defines the degree the two values are in
quadrature phase with each other at that instance, showing also which
sideband of those created (LSB or USB) has more power and at which degree.
References
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Radio modulation modes
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