Friday, 13 February 2009

The Technology Ramble

These days we tend to take technology pretty much for granted. We think nothing of being able to pick up a small object, type some numbers into it and then being able to speak to someone the other side of the world as clear as if they were in the next room. I work in a technology company and find myself equally guilty of this.The other day I was thinking back to when I were a lad and I realised how much things have changed.

Let me tell you what I mean, I was born in 1959, 2 years before Yuri Gargarin became the first astronaut or cosmonaut as he was called then. Our TV which was a large box with loads of valves (no transistors) came with BBC on it. The resolution was 405 lines and some of these were not visible so the picture was probably made up of about 395 lines or thereabouts. If you sat too close you could see the gaps between the lines as the cathode ray beam scanned across the phosphor layer the other side of the big lump of glass in front of you.

To combat this, some manufacturers fitted a switch to the back of the TV, this was called a Spot Wobbler and did what it says. It basically made the scanning beam wobble up and down and filled the gaps in.

Then ITV launched and the TV had some extra coils fitted to the tuner so we could pick this channel up. In South Wales we had TWW at the time (The West and Wales I believe). Music came on a 7inch or a 12 inch bit of plastic with a groove on either side and what was effectively a pin rested in the groove and wobbled about with the shape of the groove.

At the other end of a sort of lever assembly there was a bit of pietzo electric crystal and the wobbles created by the pin generated a small voltage. The crystal idea is similar to the thing that produces a spark in a cigarette lighter. If you were really posh, you had a magnet on the end of the lever which wobbled around inside a coil and produced a similar result to the crystal, only better.

Our portable radio took 2 batteries, one to provide the voltage for the heaters in the valves and a higher voltage one to make the rest of the radio work. Then we got a transistor radio which was about the size of a small brick and only needed one battery thanks to it's germanium transistors. The record player or Gramaphone was a huge thing that took 2 people to carry and you could place up to 7 records on top of each other so that when the first one finished playing, the next one would come smashing down on top of it and the pickup arm would descend and start playing again.

In 1967, the BBC closed down it's existing radio stations and re-opened the next day with Radio 1, 2, 3 and 4. Radio 1 opened up with a track called Theme One, then Tony Blackburn introduced Flowers In The Rain by The Move. We had exciting things like the Hit Parade on a Sunday and Terry Wogan helped us fight the flab in the afternoon.

I think it was 1969 when BBC2 opened up and we had to get a new TV and a new aerial to receive this channel. This used 625 lines to produce it's picture and the difference in quality was remarkable. The other thing that was different was the fact that it used a thing called negative modulation to produce it's signal.

Let me explain that last bit.

With 405 lines as the picture got brighter the level of the signal increased as the picture got darker the level of the signal decreased. Nothing really wrong with that except that most cars produced a lot of electrical interference which the TV thought was a high signal and displayed as a series of white dots on the screen. With 625 lines they used negative modulation, this meant that as the picture got brighter, the signal reduced and interference appeared as black dots which were not so noticeable. The other advantage was that pictures normally contain a lot of brightness, so with negative modulation when the screen was completely white, hardly any signal was coming out of the transmitter reducing it's energy consumption.

Around about this time, Britain and France made a passenger plane that could fly twice as fast as the speed of sound and then some fella called Neil Armstrong walked on the moon followed by Buzz Aldrin. Michael Collins went as far as the moon but stayed in orbit and seems to have been forgotten about.

All this happened and yet when we turned on our TV, because it still used valves you had to wait about 3 minutes or so while the heaters warmed the cathodes up enough to get the electrons moving up through the vacuum to the end and eventually we got a picture complete with sound.

Then the boffins worked out how to include a colour signal in the same space that used a black and white signal. They discovered that there were gaps in the signal and slotted the colour information in these gaps. So you would think that for backward compatibility they would broadcast a black and white signal and a red green and blue signal.

These boys are cleverer than that, they added a bit of the green signal to the the red and blue signal and then subtracted the black and white signal away from the red and blue signal and chucked all this stuff down at you. The TV then put it all back together again with the help of some resistors and an oscillator locked to a signal of 4.3361875 megahertz.

The US of course had colour TV earlier than the UK using a system called NTSC. The disadvantage with this was that if the signal bounced off something or got delayed the colour would change slightly. This is why it was called Never Twice the Same Colour. Us sensible people used a system called PAL or Phase Alternation by Line. Basically the first picture is chucked out one way up and the next is chucked out upside down. Any delays in the signal didn't change the colour, it just reduced it a bit.

The other thing about this TV signal is that the picture is not transmitted as a straight 625 lines and the lines slope slightly. What happens is that line 1 is sent out followed by line 3 then 5 etc and when it gets to the bottom, the dot flies back to the top and starts at line 2 and fills the gaps in. Now if line 1 starts at the top left and slopes slightly as it goes over to the right, then line 2 starts in the middle at the top of the screen and you get an annoying flicker at the top and bottom of the screen at 25 times a second.

How do you get round this I hear you ask? Inside the TV there is a thing called a  height control, you twidde this so that the flickering bits are off the top of the tube. You do miss a little bit of picture but not much. The clever TV people thought that there are unsused lines here, maybe we can encode some information into them and TeleText was born.

The next thing that happened was they worked out how to put all this information onto a bit of tape. Done the conventional way as in a normal audio cassette, the tape would have to fly past the heads at a very high speed and to get about an hours worth of TV programme you would need reels the size of dustbin lids. So instead of keeping the heads stationary, they stuck them on a disc and made the disc spin round as the tape went past. This means that the information on the tape is recorded as a series of diagonal strips instead of a line. Of course the head spinning round had to be synchronised to the tape or the picture would break up into a series of lines and they did this in the Philips N1500, the first domestic video recorder by using the mains.

These huge bsasts even had a timer on them which was like an analogue alarm clock and you moved the hands to set the start time. Then out came VHS and the superior Betamax, JVC managed to get Thorn EMI to use their recorders and as they owned Radio Rentals, DER Rumbelows and several other large retail companies VHS became the dominant force. Philips fought back with the N1700 and then the vastly superior V2000 system which enabled you to have a cassette that you could turn over and record on the other side and was the first system that didn't have a tracking control. The heads in the V2000 were mounted on a crystal that bent when you applied an electric current to it so the machine adjusted the heads itself for the best picture quality.

But it was VHS that won that battle in the end, mainly due to the fact that the main rental companies stocked their machines.

Then a man by the name of Clive Sinclair brought out a small home computer called the ZX80, followed by the ZX81, the latter could be bought ready made or in kit form and sported a 1Mhz 8 bit processor with 1kB of RAM. Data and programmes could be stored on a cassette if you were lucky and you could always add a 16k wobbly RAM pack. And things progressed, from the Vic 20 to Commodore 64, ZX81 to the Spectrum, Acorn Electron, BBC Models A & B, Amiga, Atari ST, Dragon 32 and 64 and many others until today the power available in a PDA today, is vastly superior to that used by NASA to make the calculations that put Neil Armstrong on the moon and brought him back again.

The Interweb thingy lets you send messages, pictures, video audio and other things across the world and you can even do that from your mobile phone. My first hard drive was 10Mb and used to take my operating system, applications, some games and my data and the lights in the street dimmed when you turned the computer on and the hard drive got up to speed.

Now I have more capacity in my phone, which can apart from being used to talk to people, play music and videos, play games, do video calling, send emails,  browse the interweb and pickup signals from satellites that pass overhead to work out where I am and tell me where I want to go. And I can even have the voice of KITT from Knight Rider give me the instructions.

But not everything has moved forward, we no longer send men to the moon, we no longer have a supersonic passenger plane, no one has come up with a design that can beat the Harrier Jump Jet. Your car still uses the same suck, squeeze, bang blow system that has been round since the 19th century and its energy is produced by a series of explosions inside a big lump of metal. Our electricity is still produced by either by burning lumps of wood that were squashed millions of years ago or by burning oil or gas and of course by a controlled nuclear explosion in a reactor.

Where are the safe nuclear fusion reactors, the cars that could run on water that were shown on Tomorrows World, teleport devices, wrist watches that let you carry out video calls and more importantly the personal Jet Pack.

The amazing thing is that I was brought into the world before ITV and have kept up with all these technological advances and have an idea of how they work and what to do if they go wrong (mild panic normally, followed by stronger panic, followed by abject terror and the Team America secret signal) and as part of my job I am expected to convey a sense of knowledge and authority to the mere mortals that call on us for help.

But ask me to do the ironing or use the washing machine and I'm buggered

That's enough for now

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