What is Modulation?
Modulation is the means whereby a signal of some type is entered into and carried by an electronic signal carrier. Within the scope of modulation, the type of signal or information that is introduced into and carried by the electric or optical signal carrier may vary, depending on the configuration of the carrier and the source of the modulation. Different types of modulation are used with various types of broadcast and communication mediums today. The use of modulation has been part of technology ever since electricity was harnessed and used for communication purposes. An excellent example of elementary modulation has to do with early telegraph technology. Using what was essentially binary code, telegraphs would forward a message that could be interpreted at the receiving end, decoded, and presented to the recipient. This form of modulation relied upon a more or less stable type of modulation that did not increase or decrease during the signaling process. Another common example of mod
Well the actual definition of modulation as it refers to CB radios involves a fairly technical explanation, but well try to keep it simple. Basically an audio-frequency wave must be combined with a carrier wave in order to be transmitted over the radio. Either the frequency or the amplitude of the radio wave may be modified. Amplitude Modulation or AM is the mode used by CB radios. When you use your CB radio and your voice enters the microphone it then goes into the modulating circuit of the radio which creates the modulation that is added to your carrier. A modulating radio wave looks very similar to a wave youd see in the ocean, except that unlike an ocean wave there is a maximum peak for a AM radio wave. This maximum peak could be explained as maximum modulation or 100% modulation. As your voice hits its loudest point the modulation peaks as well. If you are talking softly your modulation peaks will be smaller and your modulation may be less than 100%. High modulation nearing 100% i
Modulation is a prescribed method of encoding digital (or analogue) signals onto a waveform (the carrier signal). Once encoded, an inverse process called demodulation may recover the original signal. Modulation is performed to adapt the signal to a different frequency range than that of the original signal. Hence the name MODEM short for modulator/demodulator. The modem is necessary because the phone network transmits audio, not data bits. The modem is for compatibility with existing equipment. Why modulation is used? • It gives the capability of user-sharing on a single-band. If there was no modulation, for example, the voices of all radio stations would mix together. The reason that none of these stations would be interfered after modulation is because of the orthogonal property of the sin-wave. This simply specifies that as long as carrier frequencies of different modulated signals are different, in frequency domain, they wont have effect on each other. This effect can be calculated
