10 Communication Inventions That Changed the World Forever

10 Communication Inventions That Changed the World Forever

The world was never the same again.

Writing

Written communication in the form of pictures and then an alphabet.

The initial written form of communication was a pictograph. Each picture represented different actions and objects. The earliest forms of these picture words were in 3500 B.C. in an area of the world called Sumeria, that is now Iraq.

A Sumarian clay tablet 3500 B.C.

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The Egyptians came up with hieroglyphics, which was developed a few hundred years later.

Egyptian Hieroglyphics

Paper

The invention of paper was necessary once a form of written communication was invented. Paper was the surface that made written communication manageable.

At first, clay tablets were used for written communications but they were bulky and difficult to transport. The Egyptians came up with a woven surface from the papyrus plant and painted hieroglyphics on this paper. The Greeks used a parchment from animal hides. But it was the Chinese who invented the standard writing surface of paper that is still used today. While the Chinese were using paper around 100 B.C., it was not used widely in Europe for another thousand years.

The world’s oldest book from China, 868.

The invention of paper allowed those who could read and write to attain wealth and social status. It also made tax collecting and record keeping easier. Another way that the invention of paper had a profound influence on society was that history and journals could be written for future generations to read. Finally, the laws of the land could be recorded and developed on paper thereby establishing a posted code of civil conduct.

Paper can be made from wood fiber, hemp, cotton, linen and rice

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Print

The invention of printing satisfied the huge demand for books. After the invention of paper, there was a tremendous demand for books to be written. But all books had to be written by hand and this was tremendously time consuming and expensive. If you wanted to write a book you had to hire a scribe to write it and it was costly.

A 14th century scribe.

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The Chinese developed a block printing system in 868 and then a kind of movable type made of clay and then wood. The Koreans even had a movable type in the 15th century.

An example of Chinese movable block type in the 13th century.

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But it was in Germany where Johann Gutenberg developed the printing press that utilized movable type and allowed the Bible to be printed about 1453. This printing method spread throughout the continent of Europe. Suddenly books were being printed, although the rich were the only people who could afford them. The newspaper was officially created as the primary source of news for the masses.

Gutenberg Printing Press, 1453

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The printing press led to a revolution of items that were invented or reinforced. These items were religion, scientific research, journals of exploration by explorers, knowledge and study and what we know today as news reporting.

The Telegraph

It is impossible for those of us today to imagine life without our cell phones, but before cell phones were invented there was another huge milestone in the invention of the telegraph.

The telegraph was the fastest form of communication at that time and seen as remarkable. It could travel with a message at the speed of light. Samuel Morse was one developer of the telegraph and his “Morse code” of dots and dashes is still used today.

Morse’s Telegraph, 1837

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An Optical Telegraph in Germany.

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The telegraph was called “the great annihilator of time and space” in that it changed society itself through transportation in the railroads, the way war was conducted, the speed of communication between buyers and sellers and trans-Atlantic communication.

Most of all, the telegraph was pivotal in the formation of news services and agencies.

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Photography

The invention of the camera was first evident in the photographs taken during the Civil War. Suddenly war was a horror in the visual sense that was never understood even in the most graphic written descriptions. Photojournalism where “a picture says a thousand words” became popular as a picture could be internalized faster than the written words.

For the first time historical information could now be journalized in pictures and images.

President Lincoln’s Inauguration, 1861

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Civil War Photo, 1862 – Bull Run area

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Cinema

The technology of the camera led to moving pictures and the video capabilities that we have today. Movie theaters and “nickelodeons” became big hits. By 1910, there were more than 10,000 such movie houses in America. Soon filmmakers began to see the power in producing films and the potential for a huge business.

A Nickelodeon Movie Theater in Canada, 1910

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The Radio

Advances in wire telephony and the consequences of the war allowed radio to be brought into many homes worldwide. The radio was a source of entertainment as well as news for a multitude of families. The radio became the major communication source for people to receive their news.

Pearl Harbor Radio Address, 1941

Young girl listening to the family radio.

The Television

Once again the technological advancements of war paved the way for television in the 1950’s. The television in the 1950’s and 1960’s was the most wanted appliance. About 10 million Americans had a television set in the 1950’s. It soon became a huge consumer of time. People watched their news each evening as well as their various television shows. The entertainment industry now branched off from films into television. Television became a massive form of communication and generated social changes. We watched the Vietnam War and the assassination of John F. Kennedy on our televisions.

Elvis Presley, Milton Berle Show, 1956

Television in Germany, 1959

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The Computer and Internet

The digital revolution allowed computers to instantly relay information to all parts of the world. In the blink of an eye, through computers and the Internet mass communications was changed forever by bringing the people of the world together.

Newspapers and magazines are now online, as well as on paper. Music-sharing sites are online for distribution both legally and illegally. Businesses can be anywhere whether in a downtown office or in a bedroom. You can buy and sell anything online. You can pay your bills and do your banking online. You can meet people in chat areas and have online relationships. Everyone has a website and politics has invaded the Internet as well. In 2004 in the United States, 1 dollar of every eight dollars was spent online. Emailing is now more popular than “snail mail.”

Al Gore, the Internet’s creator?

Radio Shack home computer, 1970

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A microprocessor.

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Wireless Technology

Wireless portable media has overtaken our society in the presence of wireless laptops, cell phones and PDAs. Everywhere we look in public places we see the huge impact of our wireless connections. It is difficult to remember life without a cell phone or a wireless connection. I often wish I had stock in a cell phone company as I scan my own monthly bill. But with the speed of technology everything we buy today will only be more advanced tomorrow. Technology quickly becomes obsolete as something new is introduced.

Apple PowerBook, 2006

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Apple iPhone

Apple iPods

Young girl listening to the family radio.

Sounds from Space

Sounds from Space: APRS via the ISS

by Henk Hamoen, PA3GUO, The Netherlands

Did you know you can actually see with your naked eye the International Space Station (ISS) when it passes over your home? During passes when it is dark outside, early morning or late in the evening, the ISS itself is still in sunlight, and you can see it in the sky as a moving star.

It’s really fascinating to watch the ISS. But there’s even more. You can listen to the ISS as well. At a frequency of 145.825 MHz FM, licensed radio amateurs use dedicated equipment onboard the ISS for short message services, also called APRS. In very short packets of around 2 seconds (it’s digital communication), they can broadcast a message via the ISS to everyone in the ‘footprint’ (that is everyone that could ‘see’ the ISS at that very moment).

This same radio equipment is also used for voice contacts between astronauts and radio amateurs, as well as for daily for school contacts, when students ask astronauts onboard the ISS questions about their stay in space.

This video shows the ISS passing over the Netherlands (Europe) as a bright, moving star. You hear the bursts of digital communication and see them decoded on screen. LA4FPA (Norway), G6HMS (United Kingdom), IW9FRA (Italy), ON7DS (Belgium), YO8RBY (Romania), PA3GUO (Netherlands), OE1CWJ (Austria), UA1CAS (Russia) and SP9TTX (Poland) were active during this pass with their stations.

For NASA information on the amateur radio equipment, go to:

http://spaceflight.nasa.gov/station/reference/radio/

Henk Hamoen, PA3GUO, The Netherlands

http://www.pa3guo.com

The New Photonic Communications

The New Photonic Communications

A directed beam of light from a 3 Watt red Luxeon LED at a distance of almost fifteen miles, easily stands out against the lights of Salt Lake City, Utah.

Since the beginning of wireless, Amateur Radio operators have shown an insatiable curiosity to explore and populate the high frontiers of the electromagnetic spectrum. Many years ago, hams were relegated to the “shortwaves,” thought to be worthless, and they discovered that those frequencies allowed for worldwide contacts. A few years later, hams colonized the VHF and UHF frequencies and found them to be ideal for reliable local communication.

This technological wanderlust of ours may be happening again, perhaps encouraged by the Federal Communications Commission in the US, which, along with many other members of the International Telecommunications Union, has opened the frequencies above 300GHz to licensed Amateur Radio use. Small groups of hams, some in Australia, New Zealand, Tasmania and France, as well as here in the US, are experimenting with lightwaves as a communications medium.

There is some historical precedent for this. The first “wireless” electronic communication of the human voice was done in 1880, not by radio, but over Alexander Graham Bell’s “Photophone.” This device used a mirror vibrating in accord with the sender’s speech to modulate a beam of sunlight, which was detected at the other end by a selenium cell attached to a battery and an earphone.

Obviously, Bell’s invention wouldn’t help much if someone had to make a call at night, but the recent blossoming of Light Emitting Diode (LED) technology is enabling hams today to shoot a beam of concentrated light over many miles of “line of sight” territory. Because the thin beam of laser light is degraded by scintillation (“twinkling”) when propagated through a lot of atmosphere, LEDs are actually a superior transmitting tool.

Sensitive photodiode circuits behind inexpensive Fresnel lens concentrators or off-theshelf telescopes serve to receive the light and retrieve the message. How sensitive can they be? Yves Garnier, F1AVY, detected harmonics of power line frequencies in terrestrial street lighting reflected from the surface of the moon during a recent lunar eclipse. Rye Gewalt, N9LCJ, reported that output “spikes” from a photodiode receiver board he was working on were the result of the board seeing lightning strikes from a thunderstorm many miles away. Neither of these events was producing enough light to be visible to the naked eye.

Solar Radiometers

The Radiometer, also known as light windmill, was invented in 1873 by the English physicist Sir Edward Crooks. It uses light and converts it into energy & motion.

The glass globe is a sealed vacuum to prevent air resistance and the wheel is precisely balanced. The vacuum is important to the radiometer's success. If there is no vacuum (that is, if the bulb is full of air), the vanes do not spin because there is too much drag. If there is a near-perfect vacuum, the vanes do not spin unless they are held in a frictionless way. If the vanes have a frictionless support and the vacuum is complete, then photons bouncing off the silver side of the vanes push the vanes, causing them to rotate. However, this force is exceedingly small. Each paddle on the wheel has a dark side and a shiny metallic side. The dark side of the paddle absorbs more light than the metallic side creating pressure and producing motion. The radiometer works with warm light, that is sunlight or the light from electric bulbs, but not cold neon light.

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Transposer

TRANSPOSER

In broadcasting, a transposer is a device in the service area of a transmitter which rebroadcasts electromagnetic signal to the receivers which can’t properly receive the signals of the transmitter because of a physical obstruction (like a hill). A high altitude transposer receives the signals of the transmitter and rebroadcasts the signals to the area of poor reception. That’s why sometimes the transposer is also called relay transmitter or rebroadcast transmitter. Since transposers are used to broadcast a small shadow area their output powers are usually lower than that of transmitters.

PHYSICAL OBSTRUCTION
Reception of RF signals is sensitive to the size of obstruction in the path between the transmitter and the receiver. Generally speaking, if the size exceeds the wavelength the reception is interrupted. Since the wavelenth is inversely proportional to frequency, it follows than that the higher frequency broadcasting is more sensitive to objects between the transmitter and receiver. Supposing the transmitter and the receiver are at the opposite sides of a hill, while MW radio signals can be received, UHF TV signals can’t be received at all. That’s why the transposers are mostly employed for VHF and UHF broadcasting. (ie, TV and FM radio).

TRANSPOSER CIRCUITRY

The transmitters have the following stages:
• Audio (AF) or video (VF) frequency buffer stages
• Modulator
• IF stages
• Mixer
• RFamplifiers
The transposers have the following stages.
• RF input stages (RF amplifiers with AGC and band-pass filter)
• Input mixer (RF → IF)
• IF stages
• Output mixer (IF → RF)
• RF output stages ( RF amplifiers and Band-pass filter).
It should be noted that, the output stages of both devices are similar. But the input stages are quite different.
There is no AF or VF input to the transposer. The transposer receives input RF signals by means of an antenna just like a home receiver. Since received signal is already modulated there is no modulator. But instead of a modulator an input mixer is used to convert RF signal to IF signal. A second mixer (known as output mixer) converts the IF signal to output RF signal.

Spintronics

SPINTRONICS
Spintronics (a neologism meaning "spin transport electronics"), also known as magnetoelectronics, is an emerging technology that exploits the intrinsic spin of the electron and its associated magnetic moment, in addition to its fundamental electronic charge, in solid-state devices.

History
The research field of Spintronics emerged from experiments on spin-dependent electron transport phenomena in solid-state devices done in the 1980s, including the observation of spin-polarized electron injection from a ferromagnetic metal to a normal metal by Jiveshwar Sharma, Johnson and Silsbee (1985), and the discovery of giant magnetoresistance independently by Albert Fert et al.and Peter Grünberg et al. (1988).The origins can be traced back further to the ferromagnet/superconductor tunneling experiments pioneered by Meservey and Tedrow,and initial experiments on magnetic tunnel junctions by Julliere in the 1970s. The use of semiconductors for spintronics can be traced back at least as far as the theoretical proposal of a spin field-effect-transistor by Datta and Das in 1990.

Theory
Electrons are spin-1/2 fermions and therefore constitute a two-state system with spin "up" and spin "down". To make a spintronic device, the primary requirements are a system that can generate a current of spin-polarized electrons comprising more of one spin species—up or down—than the other (called a spin injector), and a separate system that is sensitive to the spin polarization of the electrons (spin detector). Manipulation of the electron spin during transport between injector and detector (especially in semiconductors) via spin precession can be accomplished using real external magnetic fields or effective fields caused by spin-orbit interaction.
Spin polarization in non-magnetic materials can be achieved either through the Zeeman effect in large magnetic fields and low temperatures, or by non-equilibrium methods. In the latter case, the non-equilibrium polarization will decay over a timescale called the "spin lifetime". Spin lifetimes of conduction electrons in metals are relatively short (typically less than 1 nanosecond) but in semiconductors the lifetimes can be very long (microseconds at low temperatures), especially when the electrons are isolated in local trapping potentials (for instance, at impurities, where lifetimes can be milliseconds).

Metals-based spintronic devices
The simplest method of generating a spin-polarised current in a metal is to pass the current through a ferromagnetic material. The most common application of this effect is a giant magnetoresistance (GMR) device. A typical GMR device consists of at least two layers of ferromagnetic materials separated by a spacer layer. When the two magnetization vectors of the ferromagnetic layers are aligned, the electrical resistance will be lower (so a higher current flows at constant voltage) than if the ferromagnetic layers are anti-aligned. This constitutes a magnetic field sensor.
Two variants of GMR have been applied in devices: (1) current-in-plane (CIP), where the electric current flows parallel to the layers and (2) current-perpendicular-to-plane (CPP), where the electric current flows in a direction perpendicular to the layers.
Other metals-based spintronics devices:
Tunnel Magnetoresistance (TMR), where CPP transport is achieved by using quantum-mechanical tunneling of electrons through a thin insulator separating ferromagnetic layers.
Spin Torque Transfer, where a current of spin-polarized electrons is used to control the magnetization direction of ferromagnetic electrodes in the device.

Applications
The storage density of hard drives is rapidly increasing along an exponential growth curve, in part because spintronics-enabled devices like GMR and TMR sensors have increased the sensitivity of the read head which measures the magnetic state of small magnetic domains (bits) on the spinning platter. The doubling period for the areal density of information storage is twelve months, much shorter than Moore's Law, which observes that the number of transistors that can cheaply be incorporated in an integrated circuit doubles every two years.
MRAM, or magnetic random access memory, uses a grid of magnetic storage elements called magnetic tunnel junctions (MTJ's). MRAM is nonvolatile (unlike charge-based DRAM in today's computers) so information is stored even when power is turned off, potentially providing instant-on computing. Motorola has developed a 1st generation 256 kb MRAM based on a single magnetic tunnel junction and a single transistor and which has a read/write cycle of under 50 nanoseconds(Everspin, Motorola's spin-off, has since developed a 4 Mbit version). There are two 2nd generation MRAM techniques currently in development: Thermal Assisted Switching (TAS) which is being developed by Crocus Technology, and Spin Torque Transfer (STT) on which Crocus, Hynix, IBM, and several other companies are working. Another design in development, called Racetrack memory, encodes information in the direction of magnetization between domain walls of a ferromagnetic metal wire.

Semiconductor-based spintronic devices
In early efforts, spin-polarized electrons are generated via optical orientation using circularly-polarized photons at the bandgap energy incident on semiconductors with appreciable spin-orbit interaction (like GaAs and ZnSe). Although electrical spin injection can be achieved in metallic systems by simply passing a current through a ferromagnet, the large impedance mismatch between ferromagnetic metals and semiconductors prevented efficient injection across metal-semiconductor interfaces. A solution to this problem is to use ferromagnetic semiconductor sources (like manganese-doped gallium arsenide GaMnAs increasing the interface resistance with a tunnel barrier, or using hot-electron injection. Spin detection in semiconductors is another challenge, which has been met with the following techniques:
Faraday/Kerr rotation of transmitted/reflected photons
Circular polarization analysis of electroluminescence Nonlocal spin valve (adapted from Johnson and Silsbee's work with metals)
Ballistic spin filtering
The latter technique was used to overcome the lack of spin-orbit interaction and materials issues to achieve spin transport in silicon, the most important semiconductor for electronics.
Because external magnetic fields (and stray fields from magnetic contacts) can cause large Hall effects and magnetoresistance in semiconductors (which mimic spin-valve effects), the only conclusive evidence of spin transport in semiconductors is demonstration of spin precession and dephasing in a magnetic field non-collinear to the injected spin orientation. This is called the Hanle effect.

Applications
Advantages of semiconductor-based spintronics applications are potentially lower power use and a smaller footprint than electrical devices used for information processing. Also, applications such as semiconductor lasers using spin-polarized electrical injection have shown threshold current reduction and controllable circularly polarized coherent light output. Future applications may include a spin-based transistor having advantages over MOSFET devices such as steeper sub-threshold slope.