Quadrature modulation principle (unfinished)

1, Principle:

General model modulated signal:

To expand, there are:

Regroup:

also because:

and so:

I, Q is a polar coordinate system representation. Wherein, I is the in-phase (in-phase) carrier amplitude, Q is an orthogonal (quadrature-phase) carrier amplitude.

Spectrum inversion:

2, the modulation and spectrum shifting

Known signal spectrum:

Is multiplied by the modulated carrier is multiplied by its spectrum

Spectrum shifting and then multiplied by its spectrum