Modulation is a cyclical one or more carriers want to transfer the mixed signal technology, commonly used in radio wave propagation and communications, the use of all aspects of data communication telephone lines and the like. Depending on the modulation signal can be divided into several bits modulation and analog modulation, these different modulation, in a different way, the signal and the carrier synthesis technology. The reverse process is called modulation demodulation for the solution of the original signal.
Significance of modulation
Spectrum signals can be move to any position, thus contributing to the transmitted signal, and the spectrum resources are fully utilized. For example, the antenna size is one tenth or larger signal, the signal can be effectively radiated. For speech signals, corresponding antenna size to be in the tens of kilometers or more, it is virtually impossible to achieve. This requires that the signal spectrum modulation process move to a higher frequency range. If you do not put the signal directly modulated radiation out, then the frequency of the radio signal emitted by each will be the same. Modulation of the substance is to make the same frequency range signals are relying on a different carrier frequency, the receiver can be isolated frequency signal required, will not interfere with each other. This is the basis to achieve multiplexed on the same channel.
