# Difference between Amplitude Modulation and Frequency Modulation

Last Updated : 16 May, 2024

Difference between AM and FM: Amplitude Modulation (AM) and Frequency Modulation (FM) are two essential techniques used in analog communication systems to convey information, such as audio signals, using radio waves. While both approaches accomplish the same purpose of modulating a carrier signal to encode information, they differ in how they modulate the carrier signal and the properties of the modulated signals they generate. Learn more about Difference between Amplitude Modulation and Frequency Modulation in this article

## What is Amplitude Modulation?

Amplitude modulation is a modulation in which the amplitude of the carrier wave changes according to the instantaneous amplitude of the modulating signal, keeping phase and frequency constant. The amplitude of the carrier wave is modified in order to send the data or information. It can transmit over long distances, and has a large range. Its modulation index varies from 0 to 1. In amplitude modulation, the frequency and phase remain the same.

## What is Frequency Modulation?

Frequency Modulation is a modulation in which the frequency of the carrier wave changes according to the instantaneous amplitude of the modulating signal keeping phase and amplitude as constant. The frequency of the carrier wave is modified in order to send the data or information. It cannot transmit over long distances, have a smaller range. Its modulation index is always greater than one. In frequency modulation amplitude and phase remain the same.

## Difference between Amplitude Modulation and Frequency Modulation

The difference between amplitude modulation and frequency modulation is tabulated below:

Amplitude Modulation Frequency Modulation
In amplitude modulation, the frequency and phase remain the same.  In frequency modulation amplitude and phase remain the same.
Its modulation index varies from 0 to 1. Its modulation index is always greater than one.
It has only two sidebands. It has an infinite number of sidebands.
It has simple circuit. It has complex circuit.
The amplitude of the carrier wave is modified in order to send the data or information. The frequency of the carrier wave is modified in order to send the data or information.
It requires low bandwidth in the range of 10 kHz. It requires high bandwidth in the range of 200 kHz.
In AM received signal is of low quality. In FM received signal is of high quality.
It works in a frequency range of 535 to 1705 Kilohertz (KHz). It works in a frequency range of 88 to 108 Megahertz (MHz).
It operates in the medium frequency (MF) and high frequency (HF).  It operates in the very high frequency.
It has poor sound quality. It has better sound quality.

## Applications of AM and FM

Amplitude Modulation (AM) and Frequency Modulation (FM) are two fundamental techniques used in analog and digital communication systems. There applications are mentioned below:

### Applications of Amplitude Modulation

• AM is extensively utilized in shortwave radio communication, especially for multinational broadcasts.
• AM is utilized in aviation communication systems, including air traffic control and aircraft-to-aircraft communication.
• AM modulation is used in two-way radio communication systems such as Citizen Band (CB) radios, Emergency Communication Systems, and Walkie-Talkies.

### Applications of Frequency Modulation

• FM modulation is used in mobile communication systems, including analog FM-based mobile networks and digital systems.
• FM modulation is widely utilized in wireless microphone systems designed for live events, broadcasting, and recording.
• FM modulation is utilized in radio navigation systems, such as VHF Omni-directional Range (VOR) and Instrument Landing System (ILS), which are used for aircraft navigation.

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## FAQs on Difference between AM and FM

### Which is better amplitude modulation or frequency modulation?

Frequency modulation is better as the sound received through it is better in quality but travel short distance

### Why is FM better than AM?

FM is better because it produces better sound quality due to higher bandwidth

### Where do we use AM and FM?

We use AM in TV signals and FM for radio and audio signals

### Do cell phones use AM or FM?

Most of the current generation mobile phones use FM

### Why AM has more noise as compared to FM?

AM has more noise as compared to FM because it has lower bandwidth and noise is added during signal transmission

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