Wednesday, November 4, 2009
History of Communications
HISTORY OF COMMUNICATIONFrom early civilizations to today the ways in which we communicate have been improved by the advancements made by technology. Communication can be defined as the transmission of sound, written symbols (written language), and images. Today's instantaneous communication is made possible only because of the types of devices we use and the network systems that are in place to carry this information.
People have always communicated and one of the first methods fire. It provided a focal point so that early people could gather together, feel safe, and share stories. Later it was used as a means of signaling other groups over relatively long distances. The invention of the wheel has also improved how people communicate. It allowed people to carry messages more quickly over longer distances. A good example would be the early mail services that used horse and cart.
As you work through this assignment you will begin to understand the role that these and other inventions have contributed to the ways in which we communicate.
Communications Technology Time line:
The following is a time line of events that have made a significant impact on the ways in which we have communicated. The information is divided into different ages with the important invention/discovery noted.
| Ancient, Classical and Dark Ages (500 000 B.C. - 900 A.D.) |
| - Discovery of Fire (c. 500 000 B.C.)
- Use of Art to Communicate (c. 100 000 B.C.)
- The First Calendar (4241 B.C., Egyptians)
- The Invention of the Wheel (3500 B.C., Mesopotamia)
- The First Written Language (3200 B.C., Sumerian
|
| Middle Ages, Renaissance and The Enlightenment (900 - 1800) |
| - The Invention of Movable Type (1041, Pi Cheng)
- The Invention of the Printing Press (1450, Johannes Gutenburg)
- The Adding Machine (1642, Blaise Pascal)
- The Development of Binary Notation (1679, Gottfried Wilheim Von Leibniz)
- The Invention of the Steam Engine (1698 Thomas Savery)
- The First Network of Communication Towers (1790, Claude Chappe)
|
| The Industrial Age (1800s) |
| - The Invention of the Photograph (1826, Joseph Niepce)
- The Development of the Electrical Generator (1831, Michael Faraday)
- The Invention of the First Mechanical Computer (1837 Charles Babbage)
- The Invention of the Telegraph (1837, Cooke and Wheatstone)
- The Development of Morse Code (1843, Samuel Morse)
- The Invention of the Telephone (1876, Alexander Graham Bell)
|
| The Modern Age (1900 - 1960) |
| - The First Transatlantic Radio Message (1901, Marconi)
- The Invention of the Television (1926, John Logie Baird)
- The Invention of the Walkie-Talkie (1938, Al Gross)
- The Development of the Electronic Computer ENIAC (1946, Mouchly, Presper, and Eckert)
- The Invention of the Transistor (1948, Bardeen, Brattain, and Shockley)
- The Development of the Integrated Circuit (1959, Jack St. Clair Kilby)
|
| The Information Age (1960 - Present) |
| |
Wednesday, October 28, 2009
Pictures of the communication devices
Tuesday, October 27, 2009
Communication technologies
Communication is the the transmission and reception of meaningful information.Through various technological devices such as the telephone,telegraph, radio, television,radar,radio telescope, orbiting satellites, microwave relays and lasers as well as the advances made in the field of electronics human communication is the beneficiary of immeasurable favors.Fundamental to these modes of communication is the conversion of light and sound to electrical energy , and the use of electromagnetic waves for the transmission and reception of information.
Contributors to the development of telephone
Alexander Graham Bell
He is the acknowledge inventor of the telephone.
he is given the credit as the inventor of the telephone. The first telephone model was made by his assistant ,
Thomas Watson.
Hans Cristian OerstedHe discovered the electromagnetism.
On 21 April 1820, while preparing for an evening lecture, Oersted noticed a compass needle deflected from magnetic north when electric current from a battery was switched on and off. This deflection convinced him that magnetic fields radiate from all sides of a wire carrying an electric current, as do light and heat, confirming a direct relationship between electricity and magnetism. Three months later he began more intensive investigations and soon thereafter published his findings, showing that an electric current produces a magnetic field as it flows through a wire.
Michael Faraday
He is the acknowledge father of modern electricity.His discovery is the reverse of Oersted's. While Oersted's experiment demonstrated that current carrying conductors produce a magnetic field produces or induces current. He demonstrated that a changing current in a coil induces current in a nearby coil even if the coils are not physically connected. This is called the principle of electromagnetic induction.
with this principle Faraday built the worlds first electric generator.
Joseph Henry
He work on the same experiments on electrical induction as Michael Faraday But he did not publish them first. He showed that electromagnetism can be used to communicate with. In a class Demonstration that he performed he showed how an electromagnet with current can attracted an iron bar which in turn struck a nearby bell. This was considered a case of electrical signaling.
James Clerk Maxwell, Heinrich hertz and Guglielmo Marconi
Maxwell put together he principles of Oersted, Faraday, and others and predicted the existence of electromagnetic waves. Twenty years later Hertz experimentally showed the existence of such waves which he called radio waves. Marconi use radio waves to send messages without wires.
Thomas Edison
He devised the carbon transmitter,it works on the principle that the electrical resistance of carbon changes with acoustic pressure exerted on it.
Lee De Forest
He built a vacuum tube, the triode which made possible the building of a nationwide telephone system. On January 25,1915, the first transcontinental telephone system line using three vacuum tube reapeters opend between New York city and San Fransisco-The worlds longest telephone line .This invention ushered in te electronic age for telephone.
"The telegraph uses a special code ,the Morse code in transmitting messages. The Morse code assigns unique pattern for each character of the alphabet, as well as to the ten numerals and punctuations"
Thursday, August 13, 2009
"CORY MOTHER OF DEMOCRACY"
"A WOMAN IN A YELLOW" was PRESIDENT CORY AQUINO,stood up for the Filipinos and fight for democracy of our own country Philippines. Cory Aquino stopped the martial law thus giving the Filipinos freedom, she was really a true mother of democracy. She said to herself, she did not know anything about the presidency, but she accepted the challenge, unified the Filipino people, and gave us a new found freedom. She led the EDSA Revolution but it was not a bloody revolution by not using weapons but using a prayer to win back their freedom from the late President Ferdinand Marcos by stopping martial law. She will be remembered as the light in our darkest hour, the one who unified our country in life and in death. As word spread about her death, people went to her home to pray in silence for her; some left flowers, notes, and cards. The whole city of Manila, gripped with grief, was adorned with yellow ribbons and banners. And even before her remains arrived at the wake, people started lining up to pay their last respect.“This is in honor of our ex-president, to show how much we love her for what she did for us in changing from the Marcos regime to a new democracy.” What she did will remain to the Filipinos heart forever and ever. THANK YOU PRESIDENT CORY for bringing back our freedom.
