Communication is basically interaction among people or sharing information. As we all know that we have mainly two types of communication.
- Analog communication
- Digital communication
Digital communications mean transferring data from one place to another. It is done by physical path or physical connection. In digital communication, digital values are taken as the discrete set. It is bit complicated as compare to analog communication and its also fast and appropriate in modern situations.
Here we have some central examples of digital communication
- Online Games:
- E-Mails (Electronic mail)
Sending short messages from one mobile phone to another.
- SMS (Short Message Service)
It is a method of sending and receiving messages from one computer to another.
Elements of Communication Systems
- Modulation: Modulation converts message signal or bits into amplitude, phase, or frequency of a sinusoidal carrier (Am, FM, QPSK). Modulation may make the transmitted signal robust to channel impairments.
- Amplitude modulation: The first method is Amplitude modulation. The amplitude modulation wave is created by multiplying the amplitude of sinusoid carrier with the message signal.
S(t) = m (t) c(t)
- Phase Modulation: In digital PM, the delivery service point transfer hastily, rather than continuously back and forth.
- Frequency Modulation: FM is a distinction of angle modulation. Both PM and FM signals are theoretically the same, the only dissimilarity being in the first case phase is modulation directly by the message signal and in FM case, the message signal first integrated and then used in place of phase.
- Coding: coding is the procedure in which digital data is converted into digital signals. We suppose that data in the form of text, numbers and graphical images, audio and video.
A communication channel is a path over which information can be pass on. This channel can be a physical path or radio waves and satellites. In this, the information is represented by individual data bits.
- Attenuation: Attenuation means loss of energy. When a signal passes through a medium it loses some of its energy in overcoming the resistance of the medium.
- Noise: Noise is random motion of electrons in a wire which creates an extra signal not originally send by transmitter.
- Distortion: Distortion means that signal changes its original form or change.
- Detection (Demodulation + Decoding): Decoding is the process of converting digital signals back into the digital data.
- Filtering (Equalization): Filtering means taking out the best result.