define modulation explain its types
Answers
Modulation is a term that is going to be used very frequently in this book. So much in fact, that we could almost have renamed this book "Principals of Modulation", without having to delete too many chapters. So, the logical question arises: What exactly is modulation?
Contents
1 Definition
2 Types of Modulation
3 Why Use Modulation?
4 Examples
5 Non-sinusoidal modulation
6 Further reading
Definition
Modulation is a process of mixing a signal with a sinusoid to produce a new signal. This new signal, conceivably, will have certain benefits over an un-modulated signal.
{\displaystyle f(t)=A\sin(\omega t+\phi )} {\displaystyle f(t)=A\sin(\omega t+\phi )}
we can see that this sinusoid has 3 parameters that can be altered, to affect the shape of the graph. The first term, A, is called the magnitude, or amplitude of the sinusoid. The next term, {\displaystyle \omega } \omega is known as the frequency, and the last term, {\displaystyle \phi } \phi is known as the phase angle. All 3 parameters can be altered to transmit data.
The sinusoidal signal that is used in the modulation is known as the carrier signal, or simply "the carrier". The signal that is used in modulating the carrier signal(or sinusoidal signal) is known as the "data signal" or the "message signal". It is important to notice that a simple sinusoidal carrier contains no information of its own.
In other words we can say that modulation is used because some data signals are not always suitable for direct transmission, but the modulated signal may be more suitable.
Types of Modulation
There are 3 basic types of modulation: Amplitude modulation, Frequency modulation, and Phase modulation.
amplitude modulation
a type of modulation where the amplitude of the carrier signal is modulated (changed) in proportion to the message signal while the frequency and phase are kept constant.
frequency modulation
a type of modulation where the frequency of the carrier signal is modulated (changed) in proportion to the message signal while the amplitude and phase are kept constant.
phase modulation
a type of modulation where the phase of the carrier signal is varied accordance to the low frequency of the message signal is known as phase modulation.
There are 3 basic types of modulation: Amplitude modulation, Frequency modulation, and Phase modulation. ... a type of modulation where the phase of the carrier signal is varied accordance to the low frequency of the message signal is known as phase modulation.
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