Frequency modulation

Frequency modulation

By:ch. Gopi Chand

In Frequency modulation there are two types

1. Narrow Band FM 2. Wide Band FMFirst lets know about the

frequency modulation

The First Frequency Modulation was invented by Edwin Howard Armstrong in

December-18-1890

How Frequency modulation Generates

Frequency Modulation

Block Diagram of FM

Frequency Modulation

Modulation Index

IF Modulation Index (β) = 1

IF Modulation Index (β) = 25

Spectrum of Frequency Modulation

Practical Examples of Frequency modulation

Advantages of Frequency Modulation

Resilient to noise Resilient to signal strength

variations Does not require linear

amplifiers in the transmitter Enables greater efficiency than

many other modes

Disadvantages of Frequency Modulation

Requires more complicated demodulator

Some other modes have higher data spectral efficiency

Sidebands extend to infinity either side

Narrow Band FM

Modulation index is less than 1 Maximum Modulating Frequency

is usually 3KHZ and Maximum frequency deviation is 75KHZ

Block Diagram of Narrow Band FM

Spectrum of Narrow Band FM

References

B.P.Lathi, Modren Digital And Analog Communication System

en.wikipedia.org http://www.radioelectronics.com

Any Queries?

Thank You