Question

What is Frequency Deviation in FM?

Answer 1

Hint:In order to answer this question, we need to separately understand the meaning of two terms, which are frequency and deviation. Frequency is defined as the number of waves which pass through a fixed place in a given period of time. Deviation is defined as the difference between the observed value of a particular variable and some other different value.

Complete answer:
The concept of frequency deviation is used in FM radio. It is used to describe the difference between the minimum and maximum value of a frequency signal, and the nominal centre or at times carrier frequency. The term is very often mistakenly considered the same as frequency drift. Frequency drift is an unintended offset of an oscillator from its very own nominal frequency.

The frequency deviation of a radio is of great importance in relation to the bandwidth. This is because less frequency deviation implies that more channels can adjust into the same frequency spectrum. The FM broadcasting range, which is always between 87.5 and 108 MHz, uses a typical channel which spans from 100 kHz to 200 kHz, with a maximum frequency deviation of 75 kHz. This deviation of 75kHz can be both negative as well as positive.

In a simple FM signal, the carrier is present at 30 Hz, and the modulating frequency is 5 Hz.The value of the modulation index is 3, which makes the peak frequency deviation about 15 Hz. This statement implies that the frequency will vary between 15 and 45 Hz.

Note: In the frequency modulation system, the ratio of the maximum frequency deviation of the carrier to the maximum modulating frequency of this particular system is defined as the frequency ratio. The most important application of frequency ratio method is that it is used to find the relation between landslide locations which has occurred in the past. It is also used to find out each factor that affects landslides.