# Why can Carson’s rule be used to determine the bandwidth of a frequency modulation FM carrier?

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The formula that calculates this bandwidth is called CARSON’S RULE. CARSON’S RULE requires knowing the modulating frequency and the maximum frequency deviation of the transmitted carrier. … Since there are many Bessel Function sidebands beyond 180KHz, FM channels must be spaced considerably farther apart than 180KHz.

## What is Carson’s rule for FM bandwidth?

In telecommunication, Carson’s bandwidth rule defines the approximate bandwidth requirements of communications system components for a carrier signal that is frequency modulated by a continuous or broad spectrum of frequencies rather than a single frequency.

## What determines the bandwidth used by any given FM communications system?

The Bandwidth of Frequency Modulation Signal

Recall, the bandwidth of a complex signal like FM is the difference between its highest and lowest frequency components, and is expressed in Hertz (Hz). Bandwidth deals with only frequencies.

## What determines the bandwidth used by any given FM Communications System Why are two different types of bandwidth used in frequency modulated transmissions?

The bandwidth of a frequency modulated signal varies with both deviation and modulating frequency. Increasing modulating frequency increases the frequency separation between sidebands. Increasing modulating frequency for a given level of deviation reduces modulation index.

## Why bandwidth of FM is infinite?

FM generates upper and lower sidebands, each of which contain an infinite number of side frequencies. However, the FM bandwidth is not infinite because the amplitude of the higher order side frequencies decreases rapidly.

## How do I check my FM bandwidth?

Carson’s rule estimates the FM signal bandwidth as BT = 2(75 + 15) = 180 kHz which is six times the 30 kHz bandwidth that would be required for AM modulation.

## What is Carson’s rule formula?

Note 1: The Carson bandwidth rule is expressed by the relation CBR = 2( f + f m) where CBR is the bandwidth requirement, f is the carrier peak deviation frequency, and f m is the highest modulating frequency.

## What are the advantages of frequency modulation?

The main advantages of FM over AM are:

• Improved signal to noise ratio (about 25dB) w.r.t. to man made interference.
• Smaller geographical interference between neighboring stations. 