The Modulation sphere or M-space formulation is a scheme or

theory A theory is a rational type of abstract thinking about a phenomenon, or the results of such thinking. The process of contemplative and rational thinking is often associated with such processes as observational study or research. Theories may be ...

representing the system of effects of

phase modulation Phase modulation (PM) is a modulation pattern for conditioning communication signals for transmission. It encodes a message signal as variations in the instantaneous phase of a carrier wave. Phase modulation is one of the two principal forms of ...

and amplitude modulation as applied together on a

carrier wave In telecommunications, a carrier wave, carrier signal, or just carrier, is a waveform (usually sinusoidal) that is modulated (modified) with an information-bearing signal for the purpose of conveying information. This carrier wave usually has ...

. 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 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 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 In radio communications, a sideband is a band of frequencies higher than or lower than the carrier frequency, that are the result of the modulation process. The sidebands carry the information transmitted by the radio signal. The sidebands c ...

of those created (LSB or USB) has more power and at which degree.

References

* * Radio modulation modes {{physics-stub