Modulation is the process of changing (varying) a periodic wave that makes a signal capable of carrying the information.
Modulation is the process of mixing the two signals into one signal. Usually the mixed signal is a signal of high frequency and low frequency signals. By utilizing the characteristics of each signal, the modulation can be used to transmit signaling information to wider or remote areas. For example, the information signal (sound, images, data), that can be sent to another place, the signal must be superimposed on another signal. In the context of broadcast radio, the ride is the signal noise signals, while carrying the radio signal called the carrier signal (carrier). Types and the laying on of very diverse ways. That is to kind of laying on of analog signals to digital signals will be different. Laying on the sound signal will also vary with the laying on of the image signal, the signal film, or other signals.
Analog modulation is the communication that transmits signals to analog signals that time is on continuous values in a defined time interval.
In analog modulation, the modulation in response to an analog signal information.
The types of analog modulation
Amplitude modulation (AM)
Frequency modulation (FM)
Pulse Amplitude Modulation (PAM)
Digital modulation is an analog signal is modulated digital data stream berdsarkan.
Digital modulation is the process of laying on a digital signal (bit stream) into the carrier signal. Digital modulation is actually a process of varying the characteristics and properties of the carrier wave (carrier) such that the form of the result (modulated carrier) Greenworld characteristics of the bits (0 or 1) it contains. Digital modulation technique in principle is a variant of the analog modulation methods.
Digital modulation techniques:
Amplitude shift keying (ASK)
Frequency shift keying (FSK)
Phase shift keying (PSK)
Analog and Digital Modulation difference:
The fundamental difference between analog and digital modulation in the shape of the signal information. In the analog modulation, the information signal and analog-shaped analog carrier signal. While the digital modulation, the signal information in digital form and analog carrier signal.
The main difference between digital and analog modulation modulation is that the message is transmitted to a digital modulation system represents a set of abstract symbols. (For example, 0 s and ls for binary transmission system), while in analog modulation systems, the message is a continuous wave signal. To send a digital message, allocating a piece of digital modulation called time interval signal and generates a symbol representing a continuous function.
Information signal spectrum usually have a low and vulnerable to tergangu by noise. While the transmission needed to signal that has a high spectrum and modulation required to move the spectrum of the signal data, from low-band spectrum to a spectrum which is much higher. This is done on the transmission of data wirelessly (with antenna), with the growing frequency of data being sent the antenna dimensions used will shrink.
- Transmission to be efficient or easier transmission.
- Hardware problem becomes easier, if the f / fc ~ 1-10%
- Pressing the noise or interference
- To facilitate the allocation of radio frequency (published by ITUT)
- For multiplexing: the process of combining multiple signals bersamasama information to be channeled through a single transmission channel.