In 2011 our global society is moving at an ever increasing rate. Our marketing pundits were quick to coin a term to describe us as the "Nanosecond Culture". In telecommunications we have been measuring things in the nanosecond for years.
How fast is a nanosecond? A nanosecond is one billionth of a second. In mathematical terms it can be represented as 10(-9) seconds or 1/1,000,000,000 of a second. In other words it is very very very fast.
Let's try and put some perspective on this without going overboard on physics. We will start with the speed of light since fiber optic communications moves at the speed of light. The speed of light travels at 186,000 miles per second. This is how fast your voice is traveling when you make a phone call on a fiber optic network. The moon is approximately 250,000 miles from earth, so at this speed you can reach the moon in 1.3 seconds.
We are bound by the speed of light. According to Einstein if an astronaut left Earth traveling faster than the speed of light, than he would arrive before he departed. Einstein also said it would take an infinite amount of energy to accomplish this. In our current understanding this is impossible.
Back to the nanosecond. Imagine a one foot length of phone wire. This is how fast light moves in one nanosecond. If the speed of light is 186,000 miles per second then equate the nanosecond to one second of your life to 31.7 years.
In telecommunications we equate fiber optic based communications to one foot equal to one nanosecond. In radio based communications such as satellite, mobile phone and microwaves we equate the nanosecond with one gigahertz (1 GHz). Consequently the speed of transmission with your Smartphone on a 2 GHz network is 2 nanoseconds.
The next time you are on a call with someone on the other side of the world and it sounds like they are next door, try to keep the nanosecond in mind.
There are many great stories in telecommunications but Hedy Lamarr's is my favorite. She is truly a hero in modern day telecom.
Many of the wireless technologies used today for security and bandwidth efficiency can be traced back to an invention Hedy Lamarr patented during World War II. If you are using Bluetooth, a WiFi hotspot, a cordless phone, a mobile phone on the Verizon network, a wireless mouse, keyboard, printer or fax, than you are using this technology.
Despite leaving school at 16 she was a brilliant mathematician and innovator, but her beauty and talent lead her to a career as a film actress. She was from Austria and married young to an overbearing arms manufacturer. Upset by her scandalous films he would keep his young bride close to him at technological meetings and parties he hosted which included guests such as Hitler and Mussolini. It was here that she picked up many of her technical skills but the Jewish actress had a lot of distaste for her husband and his friends.
As legend has it, one night she drugged her husband, disguised herself as a maid and escaped to Paris for a divorce. Eventually she made her way to London and was discovered by Louis B. Mayer and the rest is film history. But we are here to discuss telecommunications history.
During World War II, Hedy wanted to funnel her hatred of Hitler to more than selling war bonds. From her husband's meetings she knew that radio guided torpedoes and missiles were easily jammed by the enemy. Working with composer George Antheil they developed a method of changing frequencies so sender and receiver both knew what frequency the message is broadcast at.
It works like this. Imagine you are in a car listening to a radio broadcast that is meant just for you. The DJ is going to broadcast portions of the program on one frequency, then on another, then on another. Only you and the DJ know the frequency sequence. As you listen you change the frequency on the dial of your radio in the order the DJ told you and you get all the messages sent. Anyone else listening will hear a portion of the message but will have no idea where to change their dial to receive the remaining messages. It would make no sense to them. This is termed "frequency hopping" in telecommunications.
In 1942 Hedy and George Antheil were granted patent number 2,292,387 for their "Secret Communication System". Sadly the idea was so far ahead of it's time that the patent ran out before Hedy or George Antheil's revolutionary idea was put to use. In the late 1950's government contractors researching old patents stumbled upon the Secret Communication System. With the technology of the time they used this information for torpedo guidance systems and other "spread spectrum" communications. Later frequency hopping was no longer a government secret and was utilized for wireless telecommunication systems in several different forms. With the patent expired Hedy and Antheil never made a dime on their invention. In 1997 Hedy was finally recognized for her contribution and won the EFF Pioneer award for her innovative technique. She passed away three years later.
Telecommunications is magic measured in nanoseconds. The most magical part to me is how something analog like the human voice is made digital for transport and then made analog again to the listener. All thanks to a theory first published in 1924 by a Bell Labs scientist named Harry Nyquist.
We start with frequency. Sound is represented as waves. The amount of time these waves repeat is called frequency. We measure the frequency of these waves in seconds of time and it is represented as a Hertz (Hz). 1 Hz means the wave repeated once every second.
The human voice ranges between 300 Hz and 3400 Hz. For telecommunication sampling purposes we use a frequency of 4000 Hz to make sure we capture the full spectrum with some room to spare.
Enter Harry Nyquist. In a very down and dirty description, the Nyquist Theorem states that when you sample noise you must double the amount of its frequency in order to get a close to perfect representation of it. In voice telecommunications this means a 4000 Hz voice range must be sampled 8000 times per second.
Using this information your phone system uses an algorithm called a codec (coder/decoder). The codec uses this algorithm to convert the samples from analog to digital format for transport, then digital to analog format when received. This is accomplished through a method called pulse code modulation (PCM). I am not going to explain PCM in this blog but it is an important concept to keep in the back of your mind.
Now is the real fun part. Binary data is either a "0" or "1" and is called a bit (binary digit). In digital transmission we create "letters" out of a series of 8 bits, known as an "octet" or a "byte". If we have 8 bits of information representing a sample and 8000 samples (8 bits X 8000 samples), than we need 64,000 bits per second for bandwidth to truly represent the human voice. 64 kbps ... 64 kbps ... 64 kbps ... Sound familiar?
64kbps is the voice channel in T1, the DS0, the b-channel in ISDN. It goes by many names and is found in VoIP, wireless, fiber optics, microwave and all manners of telecommunications.
Of course the more we sample something the better we represent it. However we are limited in our telecom world by bandwidth. 64 kbps for voice seems to suit us very nicely. We can easily reduce it to 56 kbps but the quality is simply not as good. I have experimented with VoIP using 32 kbps, 24 kbps and 16 kbps. The voice quality is simply horrible once the sampling rates are reduced.
My conclusion is that 64 kbps for voice is here to stay for a long time. Thank you Mr. Nyquist, your theory still stands tall 87 years later.
On the internet you can find hundreds of testimonials touting the benefits of the Newton's Telecom Dictionary. I am no exception to its praises and thought I might as well throw my hat in the ring.
Robert Newton first published his dictionary in 1984. Each year he comes out with a new edition with the exception of 2010. This just makes me even more anxious for 2011 knowing that the 26th edition will soon be on the shelves. Count me in.
Robert Newton is a hero to me. His dictionary is a brilliant balance between explaining complex subjects in easy to understand terms and tackling highly complex concepts in terms for those who understand the upper echelon of our industry's terminology. However he is not beyond throwing in a humorous quip or two to keep things light hearted. The format is in dictionary form and it is easy to quickly find the subject you are looking for.
I was first introduced to Newton's Telecom Dictionary in 1996. It was in its 12th edition and was around 900 pages. I upgraded in 2006 to the 22nd edition which was around 1200 pages. The 25th edition is around 1300 pages and contains 25,000 definitions. It is updated daily by a team of editors. This is testament to the incredible growth of the Telecommunications Industry over the past few years.
His dictionary has been by my side through thick and thin. Always there for me like an old friend ready to guide me when someone throws out a new term, cryptic acronym or long forgotten technology. I highly recommend this book for anyone, no matter what their experience or position, involved in the Telecom Industry. It has always come in handy for me.
