By MICHAEL JOHN UGLO
THIS is lecture number 14 in the Science in Action series. The topic is communication as taught in the PNG science syllabus.
Communication is a common phenomenon in both plants and animals. The absence of communication could be devastating on the very survival of an organism in question.
In PNG as not being an exception to the wider global community, the nation needs to communicate and dialogue within itself and abroad across its borders to flourish as it makes its strengths and weaknesses known so it could trade well to realise its potentials. Without such communication, it will still be enclosed in a cage to the detriment of its people now and in the future generations to come.
To communicate is to relate to one another if life. Communication is the art that has ideas that are prepared to be passed to the others.
That is communication between and among people, communication between and among plants, animals and microbes as well.
Communication in people is by means of a medium such as light and sound or via a vacuum such as radio communication in space.
A message has to be prepared by a sender and relayed to the receiver. Before the message is received by the receiver it has to be transmitted. So the three parts for communication to be achieved are the sender, transmitter and the receiver.
Encoding and decoding
A message’s preparation involves encoding of the message which is transmitted via a transmitter and then received and then decoded by the receiver to obtain the message.
Simple speech with body gestures and facial expressions contain messages.
When such message is received by the eye and the ears of the listeners then it is properly understood.
For instance, if someone had cried while talking or laughs while talking, there are completely different messages relayed to the audience or the listener.
Appropriate responses are made to the message that is received.
In radio and electronic communication, a message is encoded by a computer which uses a compiler to convert the typed or spoken message into an electronic form called the object code.
The object code is sent to the address of the recipient such as the mobile phone number of the receiver.
In radio broadcasts, a message is spoken, and voice is included with another wave called the carrier wave. The outcome of the spoken voice with the carrier wave is called a modulated wave.
This is called wave modulation that is ready to be sent to the transmitter to send to the public.
The transmitter will send the modulated wave at a particular frequency so the public can tune into that frequency to receive it.
For instance, all radio stations have an allocation of frequency range at which they broadcast. This frequency ranges are allocated to them by the authority or regulatory bodies appointed by the State.
Point-to-point communication is direct voice communication from a sender to a receiver based on the addresses which are telephone numbers. The mobile phones have both transmitters and receivers built in their central processing unit (CPU) chip so they can communicate easily.
In radio communication, a transmitter radiates the signal which comes in the form of a radio wave.
The receivers have their aerials built that can detect the electromagnetic wave as an alternating current when tuned to a particular frequency.
Once on that frequency the electromagnetic wave makes the electrons in the aerial to resonate according to the frequency’s magnitude at which the particular electromagnetic wave carries.
Then an induction of a direct current is produced from this alternating current’s frequency.
The direct current flows through a resistor or an amplifier to amplify the induced current.
Then it goes to a capacitor to produce the alternating current to be amplified to produce the actual message relayed from the radio station.
In a television broadcast it works in a similar way.
This time two things happen. Firstly, moving pictures as well as voices that accompany them are combined and then modulated and sent together.
It can be coloured or monochrome. Monochrome pictures appear in black-and-white.
Once when a message is received it has to be checked for errors in the encoded message.
When there is an error, a feedback message is sent for the sender to re-transmit the message.
There are correction measures called redundancy or redundancies built to do an automatic correction of errors to be made when an error is detected.
This is known as a negative feedback. A positive feedback is the acknowledgement that the message has been received correctly without any errors.
My prayer for PNG today is: “Though the mountains may fall and the hills turn to dust, yet the love of the Lord will stand, as a shelter for all who will call on His name. Sing the praise and the glory of God.”
Next week: Electronics and technology
Michael Uglo is the author of the science textbook “Science in PNG, Pacific, Asia and the Caribbean” and a lecturer in avionics, auto- piloting and aircraft engineering. Please send comments to: [email protected]