What is the deviation ratio for an FM phone signal with a maximum frequency deviation of ±5 kHz and a maximum modulation rate of 3 kHz?

The deviation ratio is a crucial metric in frequency modulation (FM), as it helps determine the bandwidth and the performance of the FM signal. It is calculated by dividing the maximum frequency deviation by the maximum modulation frequency.

In this case, the maximum frequency deviation is ±5 kHz, which means the absolute maximum deviation is 5 kHz. The maximum modulation rate, or the frequency of the modulating signal, is given as 3 kHz. To find the deviation ratio, you would calculate it as follows:

Deviation Ratio = Maximum Frequency Deviation / Maximum Modulation Frequency

Deviation Ratio = 5 kHz / 3 kHz

Deviation Ratio = 1.6667, which rounds to approximately 1.66.

This value corresponds to the option, indicating that the calculation aligns accurately with the given options. The other choices, being either higher or lower, do not reflect the actual calculated deviation ratio based on the parameters provided. Understanding the deviation ratio's calculation is essential for grasping how frequency modulation works and its impact on signal quality and bandwidth.