Transmission Bandwidth and Signal Power in AM and FM

Introduction:
Transmission bandwidth is the range of frequencies occupied by a signal transmitted through a communication channel. In AM and FM modulation, the signal power is an important parameter that determines the strength of the signal received by the receiver. This question asks us to determine the effect of an increase in the transmission bandwidth on the signal power in AM and FM.

Effect of Increase in Transmission Bandwidth:
As the transmission bandwidth increases, the range of frequencies occupied by the signal also increases. This means that more frequencies are available to carry the signal, resulting in a higher fidelity signal. However, the signal power remains the same in both AM and FM modulation.

Explanation:
In AM modulation, the amplitude of the carrier signal is varied in proportion to the modulating signal. The amplitude of the modulating signal is added to the amplitude of the carrier signal, resulting in an amplitude-modulated signal. The power of the AM signal is proportional to the square of the amplitude of the signal. As the transmission bandwidth increases, the range of frequencies occupied by the signal increases, but the amplitude of the signal remains the same. Therefore, the signal power remains the same in AM modulation.

In FM modulation, the frequency of the carrier signal is varied in proportion to the modulating signal. The frequency deviation of the FM signal is proportional to the amplitude of the modulating signal. The power of the FM signal is proportional to the square of the amplitude of the modulating signal and the frequency deviation. As the transmission bandwidth increases, the range of frequencies occupied by the signal increases, but the amplitude of the modulating signal remains the same. Therefore, the signal power remains the same in FM modulation.

Conclusion:
In conclusion, the received signal power in AM and FM modulation remains the same with an increase in the transmission bandwidth. However, the fidelity of the signal increases in both modulation techniques due to the availability of more frequencies to carry the signal.