Morse Code, Telegraph, Binary System, Bit, Byte, Bitstream, Dialup Modems, Broadband, Cable Modem and Coaxial Cable

Posted by PITHOCRATES - August 8th, 2012

Technology 101

One of the First Improvements in Communication Speed was Morse Code sent on a Telegraph

The Battle of New Orleans (1815) was a great American victory over the British.  General Andrew Jackson with a force of about 4,000 repulsed a British force of some 11,000.  It was a huge American win.  The biggest in the war.  And a humiliating British defeat.  Now here’s an interesting side note about that battle.  The war was already over.  We had already signed a peace treaty with the British.  And were already repairing that special relationship between the United States and Britain.  So why was there even a Battle of New Orleans?  Because there was no Internet, television, radio or telegraph back then.  There was only ink and paper.  And foot, horse and boat.  Making communications slow.  Very, very slow.

The American Civil War, like the Crimean War, was a war where the technology was ahead of the tactics.  Four years of fighting with modern weapons using Napoleon tactics killed over half a million Americans by 1865.  After General Grant flushed General Lee from the Petersburg defenses he chased him as Lee fled west.  With General Sheridan’s cavalry in hot pursuit.  Cutting in front of Lee’s army to bring on the Battle of Sayler’s Creek.  Where the Confederates suffered a crippling defeat.  General Sheridan telegraphed General Grant, “If the thing is pressed, I think that Lee will surrender.”  President Lincoln was monitoring the military wires in Washington.  When he read Sheridan’s message he quickly sent a wire to General Grant.  “Let the thing be pressed.”  Grant pressed the thing.  And Lee surrendered at Appomattox Courthouse.

In 50 years time communications went from taking weeks.  To taking as little as minutes. The benefit of faster communications?  At the Battle of New Orleans approximately 2,792 people were killed, wounded or went missing.  In a battle fought after the war was over.  Only word hadn’t gotten to them yet.  So fast communications are a good thing.  And can prevent bad things from happening.  And one of the first improvements in communication speed was Morse code sent on a telegraph.  A wire between two places.  With a key switch and an electromechanical device at each end.  When an operator tapped the switch closed an electrical current went down the wire to the electromechanical device at the other end of the wire, inducing a current in it that opened and closed a device that replicated the keying at the other end.  Thus they could send a series of ‘dots and dashes’ through this wire.  The operator encoded the message at one end by assigning a series of dots and/or dashes for each letter.  The operator at the other end then decoded these dots and dashes back into the original message.

Getting Outside Information into your Computer was a little like Getting Information over a Telegraph

Morse code is a binary system.  Just like the ‘bits’ in a computer system.  Where each bit was one of two voltage levels.  Represented by 1s and 0s.  Eight bits make a byte.  Like the telegraph operator a man-machine interface encodes information into a series of bits.  The computer bus, registers and microprocessor ‘grab’ bytes of this bitstream at a time.  And then processes these bits in parallel blocks of bytes.  Unlike the telegraph where the encoded message went serially down the wire.  The telegraph greatly increased the speed of communications.  But a telegraph operator could only encode and send one letter of a word at a time.  So he couldn’t send many letters (or pulses) per second.  Just a few.  But when you encode this information into 8-bit chunks you can greatly increase the speed data moves inside a computer.  As computer speeds grew so did their bus size.  From 8 bit to 16 bit (2 bytes).  From 16 bit to 32 bit (4 bytes).  From 32 bit to 64 bit (8 bytes).  As a computer processed more bytes of data at a time in parallel computers could increase the speed it completed tasks.

Of course, people who were most interested in faster computers were gamers.  Who played games with a lot of video and sound information encoded in them.  The faster the computer could process this information the better the graphics and sound were.  Today computers are pretty darn fast.  They can run some of the most demanding programs from 3-D gaming to computer-aided design (CAD).  But then a new technology came out that made people interested by what was happening outside of their computer.  And how fast their computer was didn’t matter as much anymore.  Because getting that outside information into your computer was a little like getting information over a telegraph.  It came in serially.  Over a wire.  Through a modem that attached a computer to the Internet.  And the World Wide Web.  Where there was a whole lot of interesting stuff.  But to see it and hear it you had to get it inside your computer first.  And the weak link in all your web surfing was the speed of your modem.

A modem is modulator-demodulator.  Hence modem.  And it worked similar to the telegraph.  There was a wire between two locations.  Typically a telephone line.  At each end of this wire was a modem.  The wire terminated into each modem.  Each modem was connected to a computer.  One computer would feed a bitstream to its modem.  The modem would encode the 1s and 0s in that bitstream.  And modulate it onto a carrier frequency.  The modem would output this onto the telephone line.  Where it traveled to the other modem.  The other modem then demodulated the carrier frequency.  Decoded the 1s and 0s and recreated the bitstream.  And fed it into the other computer.  Where the computer grabbed bytes of the bitstream and processed it.

The Coaxial Cable of Broadband could Carry a wider Range of Frequencies than the Twisted Pairs of Telephone Wire

The speed at which all of this happened depended on your modem.  Specifically your modem.  The other modem you connected to was typically on a web server and was of the highest speed.  And on all of the time.  Unlike the early dialup modems we used in the Nineties when we first started surfing the web.  Back then surfing could be expensive as you often paid for that time as if you were on the telephone.  This was the other weak link in surfing.  Trying to make that telephone line as short as possible.  Because that was what you paid for.  The use of the telephone line.  Once you got onto the Internet you could travel anywhere at no additional cost.  So you dialed in to an available local number.  Which sometimes could take awhile.  And when you finally did dial-up on a local line but went inactive for a period of time it disconnected you.  Because others were looking for an available local phone line, too.

The first modem speeds many of us used at the beginning were 2400 bits per second (bps).  Which was a lot faster than the few bits per second of a telegraph operator.  And okay for sending email.  But it was painfully slow for graphics and sound.  And then the improvements in speed came.  And they came quickly.  4800 bps.  9600 bps.  14400 (14.4k) bps.  28800 (28.8k) bps.  33600 (33.6k) bps.  And then the last of the dialup modems.  56000 (56k) bps.  Which meant you could download up to 56,000 bits per second of 1s and 0s.  That’s 56,000 pieces of information coming out of that modem each second.  Now that was fast.  Still slower than what happened inside the computer with those wide parallel buses.  That chomped off huge bytes of data.  And processed them at rates in excess of a billion times a second.  But it was still the fastest thing on the block.  Until broadband arrived.

Today you can buy a broadband cable modem for less than $100 that can download at speeds in excess of 100,000,000 bits per second.  That’s over 100 million pieces of information each second.  It is only data rates like this that let you live stream a movie off the Internet.  Something that the 56k modem just wouldn’t do for you.  And it’s always on.  Costing you a flat fee no matter how long you spend surfing the web.  You turned on your computer and you were connected to the Internet.  What allowed those greater speeds?  The wire.  The coaxial cable of broadband could carry a wider range of frequencies than the twisted pairs of the telephone wire.  Providing a greater bandwidth.  Which could carry more encoded information between modems.  Allowing you to download music and videos quicker than it took a telegraph operator to send a message.


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Music, Radio Transmitters, Radio Receivers, CD Players, Compression, MP3 Players, Internet, YouTube, Live Streaming and Music on Demand

Posted by PITHOCRATES - February 29th, 2012

Technology 101

The Roaring Twenties brought Electrical Power and Broadcast Radio into our Homes

We take music for granted today.  We can listen to pretty much anything we want to.  At any time.  In any place.  In the home.  In the car.  At the gym.  It’s nice.  You can listen to some of the most beautiful music at your convenience and leisure.  It wasn’t always like this, though.  During the time Edvard Grieg composed his masterpieces few could listen to them.  Unless you attended a live performance.  Which weren’t that readily available.  Unless you lived in a big city.  Where a symphony orchestra could include some of his music in a performance.  But you had to listen to what they played.  And what they played was the only music you were familiar with.  Unless you had a friend with a piano.  Who could read sheet music.  And was a concert-level pianist.  Again, something not that common.

But today you can click on a computer link and listen to almost any obscure piece of music there is.  From Grieg’s beautiful Bådnlåt (At the Cradle), lyric piece for piano, Op. 68/5.  To something really esoteric like Sparks’ As I Sit Down To Play The Organ At The Notre Dame Cathedral.  You can listen to them.  You can buy them.  Download them to a portable MP3 player.  And take them anywhere.  Just imagine trying to do this in 1899.  Going to the lake.  And wanting to listen to Grieg’s new lyric piece for piano.  Opus 68.  Number 5.  At the Cradle.  Unless you took a piano and a concert-level pianist with you that just wasn’t going to happen.  But this all changed.  Beginning around the dawn of the 20th century.

Nikola Tesla had recently won his war with Thomas Edison.  His AC power replaced Edison’s DC power as the standard.  And in the 1920s we were electrifying the country.  We began to generate and transmit AC power across the land.  To businesses.  And to homes.  Where we could plug in the new electrical appliances coming to market.  We were working on another new technology during this time.  Something that could plug in at home to the new electrical power.  The radio.  This technology had something to do with electromagnetic fields and waves.  Transmitted between antennas.  One on a transmitter.  And one on a receiver.  As long as the transmitter and the receiver were tuned to the same frequency.  The first use of this new technology was in the form of a wireless telegraph.  Which few people had in their homes.  These were more useful to communicate with others who were not connected by telegraph lines.  Like ships at sea.  Where we sent Morse code (those dots and dashes that spelled words).  Which worked well.  As long as all the ships didn’t tried to communicate at the same time on the same frequency.  But transmitting speech or music was a different manner.  Because everyone talks more or less in the same band of frequencies.  And notes played on one violin tend to play at the same frequency on another violin.  So if some radio transmitters broadcasted different concerts at the same time you wouldn’t hear a nice concert on your radio.  You’d hear a cacophony of noise.  To get an idea what that would sound like open up three or four browser windows on your computer.  And play a different song on YouTube in each.  What you hear will not be music.  But noise.

In the Eighties we traded our Phonograph Needles for Laser Beams in our CD Players

Of course, this didn’t stop the development of commercial broadcast radio.  For we tune radio transmitters and radio receivers to the same resonant frequency.  The transmitter transmitting at one frequency all of the time. While the radio receiver could tune in to different frequencies to listen to different radio broadcasts.  When you turned the radio tuning dial you changed what resonant frequency your receiver ‘listened’ to.  Which was basically a filter to block all frequencies but the tuned frequency from entering your radio.  We call that frequency the carrier signal.  Typically just a plain old sinusoidal wave form at a one frequency that we imprint the information of the speech or music on.  The transmitter takes the music waveform and modulates it on the carrier signal.  Then broadcasts the signal on the broadcast antenna.  The receiver then captures this signal on its antenna.  And demodulates it.  Pulling the musical imprint from the carrier signal.  And restoring it to its original condition.  Which the radio than amplifies and sends to a speaker.  I left some steps out of the process.  But you get the gist.  The key to successful broadcast radio was the ability to transform the source signal (speech or music) into another signal.  One that we could transmit and receive.  And transform back into the source signal.

The Roaring Twenties was a Neil Armstrong moment on earth.  It was one giant leap for mankind.  For it was in this decade that the modern world began.  Thanks to Nikola Tesla and his AC power.  Which allowed us the ability to plug in radios in our homes.  And power the great radio transmitters to get the signal to our houses.  Tesla, incidentally, created radio technology, too.  Well, Tesla, and Guglielmo Marconi.  (Patent disputes flared between these two greats about who was first.)  Great technological advancement.  Created during a time of limited government and low taxes.  That unleashed an explosive amount of creativity and invention.  The Eighties was another such decade.

The Eighties launched the digital age.  The world of bits and bytes.  1s and 0s.  Digital watches.  Clocks.  Calculators.  PCs.  And, of course, our music.  For the Eighties gave us the compact disc.  The CD.  Music that didn’t wear out like our vinyl records.  And didn’t pop or hiss with age.  Because a CD player didn’t have a phonograph needle.  That rode the groves on our vinyl records.  It had something far more futuristic.  A laser beam.  That reads information encoded into the CD.  Information encoded onto a reflective layer through a series of pits.  During playback the laser either reflects or doesn’t reflect.  This information is than processed into a series of 1s and 0s.  Then converted into the analog waveform of the source material.  And becomes music again.

The Eighties gave us the Digital Age which led to the Internet and Music on Demand

This process is similar to the process of broadcast radio.  Not in any technological way.  But by changing a source signal into something else.  And then converting it back again.  In the case of the CD we sample an analog signal (i.e., an audio recording).  By taking ‘snapshots’ of it at regular intervals.  Then convert these snapshots into a digital format.  And then transfer this digital information to the reflective layer on a CD.  Those 1s and 0s.  When we play it back the laser reads these 1s and 0s.  Then converts these digital snapshots back into the original audio signal.  Sort of like modulating and demodulating a signal.  Only instead of modulating we’re converting from analog to digital.  Then vice versa.

The quality of the digital format depends on how much information each snapshot contains.  And the interval we sample them at.  Larger chunks of information taken in short intervals contain a lot more information.  And improve the quality of the sound.  But it will also take up a lot of space on those CDs.  Limiting the number of songs we can encode on them.  Which lead to compression.  And MP3s.  Which worked on the premise that there’s a lot of music in music.  But we don’t necessarily hear all of that music.  Some sounds mask out other sounds.  Certain frequencies we barely hear.  So while the CDs tried to reproduce the music as faithfully as possible, we learned that we could discard some of the information in the music without reducing the quality of the music much.  This saved a lot of space on CDs and portable MP3 players.  Allowed faster downloads on the Internet.  And live streaming.

The Roaring Twenties changed our world.  Modernized it.  And gave us many things.  Including broadcast radio.  And music in our homes we never had before.  And the Eighties also changed our world.  Further modernizing it.  Giving us the digital age.  That led to the Internet.  And music on demand like we never had before.  Where we can listen to anything.  No matter how obscure.  It’s now all available at our fingertips.  To listen online.  Or to buy and download to a portable device.  From Grieg to Sparks.  And everything in between.


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