Concept
As the implementation technology of the current MQAM, the modulation process can be completed directly by digital signal processing, and the shape of the carrier modulation is not visible from the form of the transmitted signal. Therefore, this type of signal processing generates the MQAM band pass signal signal is called "No Ampline Monitor" (CAP).
No venetion modulation does not perform transform domain processing, just a variation of equivalent representation. The MQAM signal process is implemented by the signal processing, and the information of the baseband signal is transmitted to a dominant signal of the appearanceless carrier by means of a signal processing.
Therefore, the so-called "no carrier" said that it is not practical, just borrowing a statement, indicating that MQAM is different from conventional modulation techniques in a signal processing method.
Working principle
Translated by conventional MQAM to "no carrier" form, MQAM is:
in 2 orthogonal base functions as orthogonal carriers, ie
Both mutually orthogonal signals are tongue signals in