How does a wirless device communicate?

How does wireless communication takes place?

In my last post I have given you a brief description of the history of communication. In this post we will see the basic communication system

SOURCE

A source in communication is a signal that carries information . Consider your speech when you talk or the music that you hear or pictures that you see are basically sources of information. Now our main objective is to send this source of information from one point to another.

INPUT TRANSDUCER

Now as you know that the source may or may not emit electrical signal. For e.g.: the speech when you speak is a sound signal and we cannot send a sound signal in an electrical channel. For this we convert that sound signal into electrical signal. This conversion of one form of signal to another form is done by transducer.

TRANSMITTER

The function of a transmitter is to process the signal . For e.g. in telephone communication the voice band is 3100 Hz, so signals above it are either eliminated or band restricted. Thus in order to make the information suitable for transmission over channel the signal is modulated, amplified and band restricted.

CHANNEL AND NOISE

The channel is the medium through which information travels from transmitter to receiver . So far we have seen how sound signal is converted to electrical signal and modulated inside the transmitter. This modulated signal is send to the receiver end and this could be done by sending the signal through the medium called channel. The media can anything, say telephone wires, coaxial cables, optic fibers, wireless or via microwave. When the information travels though a channel it is affected by noise. Noise is nothing but distortion or interference generated by the channel.

I am later going to discuss about various types of noises and channels used in communication.

RECEIVER

The receiver receives the signal from the channel. After receiving the signal its tries to extract the original message/information signal known as demodulation. It’s also checks if there is any error or noise present in the signal.

OUTPUT TRANSDUCER

The person at the transmitter has sent a message signal in the form of speech. After processing the signal it changed to electrical form. So our desired output should be in the form of sound signal and not electrical signal. So in order to bring back the original sound signal we use a transducer.

DESTINATION

The place where we want to send the signal. It can be loudspeaker, T.V, computer etc