High-Level modulators:
This type of modulator is defined by one which modulates a high-power section of the circuit (RF amplifier). The advantage is that those linear amplifiers are not required for amplification stages. The drawbacks are that high power audio amplifiers are required.
Low-Level modulators:
This type of modulator applies to low power stage of the transmitter mostly in RF generation stages or through the digital signal processing areas. The drawback is the requirement of linear amplifications required for radio frequency stages
