 # SIGNAL&SYESTEM(1)

#### What is a signal?Generally, Every sign represents it.So everything around us represents it.Likewise, your is using a smart-phone, it’s a cellular network.

cellular network or mobile network is wireless based communication system.Also known as a network signal.Digital signboards represent a digital signal.

A  signal is an electric current or electromagnetic field.It conveys data from one place to another. The simplest form of signal is a direct current (DC).That is switched on and off and it is represented as ‘0’ & ’1’ in a digital logic gate.This is the same principle by which the early telegraph worked. More complex signals consist of an alternating-current (AC) or electromagnetic carrier that contains one or more data streams.

The concept of it is mainly based on waveforms. A waveform is the shape and form of a signal such as a wave moving in a physical medium or on a discrete object.

Basically, there are two types of signals –

• Continuous
• Discrete

Continuous signals are defined and represented at any instant of time.The phase shift  180° happens in infinite time sequence. These signals have a finite or infinite sequence with time. Continuous is also called analog signals. The examples of continuous are sine, cosine, and triangular waves.

Figure 1(a) represents it, Now let’s discuss this continuous wave.First question, why this is a continuous wave?We all can see the wave has a starting value of 1 (this value can be any number ). λ represents wavelength and X-axis is time division. Now, this is a continuous signal because in the figure the wave is represented by instant time.

Discrete signals are defined and represented at the certain time. Here the time sequence a finite or countable set. Discrete is also called digitalized signals.

Figure 1(b) represents it, In the figure the time (t) is countable.So, this signal is called a discrete signal.

As there are the more signals. Deterministic & Non-deterministic .Also known as a random signal.Periodic & Aperiodic and Even & Odd are discussed in the next blog.

For any question comment in the comment section.

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