Topic: Communication Systems
When a carrier is phase modulated, with an integrated modulating signal, the resultant is
- A. Phase modulated signal
- B. Frequency modulated signal
- C. Amplitude modulated signal
- D. QPSK modulated signal
Answer: B. Frequency modulated signal
Explanation: Frequency modulation (FM) and phase modulation (PM) are closely related. If the message signal is integrated before being applied to a phase modulator, the instantaneous frequency (which is the derivative of the phase) becomes proportional to the original message signal, resulting in Frequency Modulation.