What is an advantage of using I-Q modulation with software-defined radios (SDRs)?
The need for high resolution analog-to-digital converters is eliminated
All types of modulation can be created with appropriate processing✓Bonne réponse
Minimum detectible signal level is reduced
Automatic conversion of the signal from digital to analog
Explication
Every modulated signal can be described as some path of amplitude and phase over time, and an I-Q pair can express any such path, so the modulation type becomes purely a question of the processing applied. I-Q modulation does not remove the need for good converters or lower the noise floor.