Emitter modulator amplifier for Amplitude Modulation operates in class A mode and has a very low efficiency. The output of the modulator is very small, therefore, it is not suitable for modulation at high level.

What is an emitter modulator?

In emitter-injection modulation, the gain of the RF amplifier is varied by the changing voltage on the emitter. The changing voltage is caused by the injection of the modulating signal into the emitter circuitry of Q1, as shown in figure 1-51. ... The modulation envelope is developed across the collector-tank circuit.

What does an amplitude modulator do?

Amplitude modulation (AM) is a modulation technique used in electronic communication, most commonly for transmitting messages with a radio wave. In amplitude modulation, the amplitude (signal strength) of the carrier wave is varied in proportion to that of the message signal, such as an audio signal.