In frequency modulation, what does Carson's rule determine? A. Carrier frequency B. Modulation index C. Bandwidth D. Phase deviation

Break Down the Problem

1. Identify the key concepts related to frequency modulation.
2. Understand what Carson's rule is used for in frequency modulation.

Relevant Concepts

Carson's rule is a formula used in frequency modulation to estimate the bandwidth required for a modulated signal. The formula is given by:

$BW = 2(\Delta f + f_m)$

where $\Delta f$ is the peak frequency deviation and $f_m$ is the maximum frequency of the modulating signal.

Analysis and Detail

• Carrier Frequency: This refers to the main frequency of the carrier wave, not directly determined by Carson's rule.
• Modulation Index: This is the ratio of the frequency deviation to the frequency of the modulating signal, but it is not what Carson's rule determines.
• Bandwidth: Carson's rule directly provides a method for estimating the bandwidth of a frequency-modulated signal.
• Phase Deviation: This is not determined by Carson's rule, which focuses on frequency deviation.

Verify and Summarize

Based on the understanding of Carson's rule, the primary focus is on estimating the bandwidth needed for a frequency-modulated signal. Therefore, its primary use is to determine the bandwidth of signals modulated in frequency.

Final Answer

C. Bandwidth