PULSE WIDTH MODULATION PWM Using 555 Timer IC



What is modulation?

In analog or digital communication system, it is impossible to transmit a low frequency message signal over a channel, it causes signal distortion, attenuation or signal loss. Inorder to make the transmission ideal (almost), we have to use some techniques called modulation. Modulation can be defined as the process of varying some characteristics of carrier signal in accordance with the instantaneous value of message signal. Carrier signal is a high  frequency wave generated by a local oscillator, used to carry the message signal from transmitter to reciever. The message signal which is mixed with carrier wave is called modulated signal and the process is called Modulation. The modulation is an important process in a basic communication system, which increases the transmission range, reduces the size of antenna and increases the efficiency of the system by reducing noise interference.

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