Today, i am not going to describe the signal that we people generally think in our daily life as a sign in the activities like listed below.

• If a girl smiles in front of boy,then boy thinks she likes him. Let him assume that she is in love with him.
• If a cat crosses the way we are heading ,then we think today is not good to going to happen around us.Let us assume the sign of bad things.
• If government officer shows his hand from under the table to person who is meeting with him,then person must have understanding of he is asking for something.Let person to assume that officer wants to collect some money from him to do something.
• A crow hanging near the house means an unlucky future, while others agree it’s a sure sign that someone in the house will die.Let them assume what they are adapting.

All of points mentioned above are we , generally think and adapt it as sign or signal to take as whether the bad news or good news.Let’s forget about these things and converge  our topics Signal in Engineering.

Signal terms generally referred  in three disciplinary of engineering world such as communication,signal processing and electrical engineering.We deal here Signal in terms of Communication ,fundamental of Electronics and Communication.

A signal as referred to in communication systems, signal processing, and electrical engineering is a function that “conveys information about the behavior or attributes of some phenomenon”.

Any quantity exhibiting variation in time and / or space is potentially a signal.

Signal can be divided into two parts as Analog Signal and Digital Signal.

• Analog signal
  • Voice from human beings,animals are all analog signals.
  • Our vision is a kind of analog signal as we see various shapes and colors in a manner without discontinuities.
  • An analog signal is a continuous wave depicted by a sine wave (pictured below) and may vary in signal strength or frequency . The sine wave’s amplitude value can be seen as the higher and lower points of the wave, while the frequency  value is measured in the sine wave’s physical length from left to right.

• Digital Signal
  • A logical signal is a digital signal with only two possible values(0 and 1).
  • A digital signal is a signal that is constructed from a discrete set of waveforms of a physical quantity so as to represent a sequence of discrete values.
  • Computers, CDs, DVDs, and other digital electronic devices are source of digital signals.

Here we have described the signal in terms of communication and now we are familiar with analog signal and digital signal and its pattern and even it’s example.