am modulation

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MODULATION: 

MODULATION BY- SANJAY KUMAR 0900321088 EN-2(A)

introduction: 

introduction Modulation is the process by which some characteristics of a carrier is varied in accordance with a modulation wave . Modulation is the process of putting information onto a high frequency carrier for transmission (frequency translation). such a modification is achieved by mean of a process called modulation .

PowerPoint Presentation: 

In the modulation process, the baseband signle is called “modulating signal” and anther higher frequency signal is called as the “carrier”. The carrier signal will carry the modulating signal to the destination.

Different of Modulation Method : 

Different of Modulation Method Analog modulation - The modulating signal and carrier both are analogue signal. TYPES : Amplitude modulation (AM), Frequency modulation (FM), Phase modulation (PM)

PowerPoint Presentation: 

Figure Types of analog- modulation

Digital modulation - The modulating signal is a digital signal , but the carrier is an analogue signal. TYPES : Amplitude Shift Keying (ASK), Frequency Shift keying (FSK), Phase Shift Keying (PSK) : 

Digital modulation - The modulating signal is a digital signal , but the carrier is an analogue signal . TYPES : Amplitude Shift Keying (ASK), Frequency Shift keying (FSK), Phase Shift Keying (PSK)

Amplitude Modulation: 

Amplitude Modulation Amplitude Modulation is a process of changing the amplitude of a high frequency carrier signal in proportion with the instantaneous value of modulating signal (information). Amplitude Modulation is the simplest and earliest form of transmitters.

PowerPoint Presentation: 

Figure : Amplitude modulation

AM – Basic Definitions: 

AM – Basic Definitions The AM signal: The modulating signal: The Carrier Signal:

AM Characteristics : 

AM Characteristics AM is a nonlinear process Sum and difference frequencies are created that carry the information

modulation index : 

modulation index The ratio between the amplitudes between the amplitudes of the modulating signal and carrier, expressed by the equation:

Measurement of Modulation Index: 

Measurement of Modulation Index

Overmodulation: 

Overmodulation When the modulation index is greater than 1, overmodulation is present

Modulation Index for Multiple Modulating Frequencies: 

Modulation Index for Multiple Modulating Frequencies Two or more sine waves of different, uncorrelated frequencies modulating a single carrier is calculated by the equation:

Full-Carrier AM: Frequency Domain: 

Full-Carrier AM: Frequency Domain Time domain information can be obtained using an oscilloscope Frequency domain information can be calculated using Fourier methods, but trigonometric methods are simpler and valid Sidebands are calculated using the formulas at the right

Bandwidth: 

Bandwidth Signal bandwidth is an important characteristic of any modulation scheme In general, a narrow bandwidth is desirable Bandwidth is calculated by: f C f c +f m f c -f m 2f m

applications Amplitude Modulation: 

applications Amplitude Modulation AM applications include broadcasting in medium- and high-frequency applications, CB radio , and aircraft communications

THANK YOU : 

THANK YOU