FM systems that utilize an indirect FM modulator consisting of a phase modulator stage are known as:
A) Crosby systems
B) Hartley systems
C) Armstrong systems
D) PLL systems

Question

Quizplus · Accepted Answer

Armstrong systems utilize an indirect FM modulator consisting of a phase modulator stage. This method was pioneered by Edwin Armstrong, who is credited with inventing FM radio.

FM Systems That Utilize an Indirect FM Modulator Consisting of a Phase