Define Modulation
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Explain and illustrate with the aid of simple diagram the 3 modulation techniques used today.
Definition
Modulation is the technique that modifies the form of an electrical signal so that it can carry information on a communication media.
A signal that is transmitted through any media is a sine wave. The sine wave was discovered by a Frenchman, Jean Basptise Fourier. A sine wave that does the carrying through the modem is also known as the carrier wave. A sine wave is measured in frequency (no. of cycles per second) and amplitude (how strong or high) the signal is transmitted through the media.
Every sound wave has two parts, one half above the zero point, which has a positive value and the other half below, which has a negative value and three important characteristics.
The height of the wave is called the amplitude
The length of the sound wave is expressed as the number of waves or cycles per second or frequency as expressed in Hertz (Hz)
The phase is the direction in which the wave begins
Basically there two types of modulation:
Analog Modulation (analog encoding of digital information)
Digital Modulation (digital encoding of analog information)
Analog Modulation
Modifies the form of an analog electrical signal so that it can carry information. Modulation changes the shape of the carrier wave (a sine wave) to transmit 0s and 1s...