It's mid-fall and the sky has turned a warm, deep shade of blue at an early six pm.
posted by nate on March 27, 2003
How easily we surround ourselves with technology. I could keep going and going as almost everywhere I look I find another technologically advanced element of my everyday reality. What boggles my mind is that I don't understand much about how any of it works or even how it was manufactured. LCD screens? Liquid Crystal Display? What the hell is that? The magnetic diamond stylus riding the grooves in a vinyl disk at 33 1/3 rpm produces rich, stereo sound sent by tiny (also magnetic) plastic speakers that rest next to my ears behind comfortable spongy foam. How? And the telephone ringing, a signal sent miles along wires, sharing thousands of other calls going every which way, entering my home through through two tiny, tiny wires to my digital, cordless phone. I send ten tones triggered by buttons on the keypad of my wireless receiver and the tiny, tiny wires connect me almost instantly to a distant telecommunicating device across the world. It's endless!
Everywhere you turn there's an incredibly complex device we use every day, built from years and years of accumulated human knowledge. And so few of us understand any of it.
I remember reading some time ago how one must understand the workings of a particular item to fully respect the power it held. In the interest of living this philosophy, I regularly dismantle my devices, most often in attempts to fix them but usually end up making things worse. I lose screws, snap brackets and forget how things go back together after bludgeoning delicate electronics and mechanics with my bumbling fingers. Every so often I do manage to actually make things work again, but usually I just make a mess.
I seem to be honing my own philosophy: you can't respect anything until you learn how to break it.
The phone rings and I again decide not to answer it. Instead I find myself mesmerized by the methodical digital "ring" it cries out five times before answering the call itself. The telephone system is something amazing. Technology concocted some 90 years ago sprawls across the world in the form of wires held up by oil-treated trunks. The omnipresent telephone pole has entrenched itself as a fixed element of the modern landscape. The fact that this technology has kept up with earth's population explosion without any substantial loss of service boggles my mind. Of course, mechanization and eventually computerization has helped the basic telephone system evolve and continue to exist. The most important technological advances for the telephone, however, is the fiber optic cable -- an optically pure human-hair sized strand of glass encased in reflective coating which transmits digital information in the form of light.
It all starts with two wires running to your phone: one is a common, and the other supplies 6 to 12 volts DC at about 30 milliamps. The microphone in your handset basically modulates the current, and the speaker "plays" the modulated signal. Inside the phone, a convenience device called a duplex coil keeps what you are saying into the mic from being played back on your headset speaker.
The wires from your phone go to your outlet, and then run via thick copper wire to a box by the road. From here, a large cable packed with up to 100 copper pairs runs either directly to the area's switch office, or to a refrigerator sized device called a digital concentrator. Your voice is digitized in the concentrator at 8,000 samples per second at 8-bit resolution. It will travel as digital information along a fiber optic or coaxial cable along with dozens of other conversations to the area's switch office. If you are making a local call, the switch creates a loop between your line and the person you called. If you are dialing long-distance, your voice will be digitized (if it isn't already) and combined with millions of others and sent either along a fiber-optic line, or transmitted by satellite or microwave towers to the switch office of the person you're calling.
In order to allow the most calls along phone lines, the frequencies transmitted are limited to a bandwidth of about 3,000hz. This means all frequencies below 400hz and above 3,400hz are eliminated, which explains why voices sound so distinct over the phone: some low and high tones are missing. Voices also sound different because of the low sampling rate & resolution of the digital signal.
You can still use a phone from the '20s in our modern phone system. Tapping the switch is the same as pulse dialing: 4 taps registers as a "4" being dialed. Tone dialing is accomplished by various combinations of two frequencies of tone. For example, 697hz coupled with 1,209hz signals a "1", 697hz coupled with 1,477hz signals a "3". The dial tone is a combination of a 350hz tone and a 440hz tone, the busy signal is made of a 480hz and 620hz tone in half-second cycles, and a ring is signalled by a 90-volt AC wave at 20 hertz. (Old fashioned phones used a hand crank to generate the ring-signal AC.)
Overall, the telephone is an incredibly simple system. But the fact that so many millions and millions of people and businesses are connected to the system is what makes it complex. I decide that even though I am in awe of the technology, I still don't want to answer the phone.
The record ends and the tone arm clicks into the upright position. I've been a fan of vinyl ever since I heard Miles Davis' Kind of Blue compared back-to-back with the old CD mastering (which has since improved..) I immediately set out to trade my 250 CD's for an equally extensive, albeit substantially heavier, collection of LP's. Yet I've never fully understood how the hell they work. I decided to investigate.
There are two types of cartridges used. A moving magnetic cartridge is the most common & least expensive. The moving coil is more expensive and also requires the purchase of a costly pre-amp to compensate for the low-output of the cartridge. Since this limits the moving coil crowd to the smallest portion of our Shrike fanbase: wealthy audiophile geeks, I'll stick to explaining the magnetic model.
Records have two "tracks" of a stereo signal cut into the half-mile groove of each side. One channel is cut into the depth of the record, while the second channel is cut into the walls. To read this signal, a shaft of metal (cantilever) with a diamond stylus tip rides in the grooves, vibrating a magnet on the opposite end of the shaft which ends in the cartridge body. The rapid vertical & horizontal movements of the magnet disturb the field between two coils of copper wire, which produces two electrical signals corresponding to the stereo channels. These signals are transmitted to the amplifier where they are boosted and sent along to the speakers.
The record groove can contain modulations as small as a millionth of an inch, and the effective tip pressure on the record can actually be as high as several tons.
This is due to extremely small contact area between the diamond tip & groove surface. With a decent stylus & proper care, however, records can last years without noticeable degradation. Plus, they come with beautiful, big-ass cover art.
Phonograph technology, however complex & functional, 20+ years in the development and still in use after more than 80 years, is now being phased out and forgotten. We're entering a stage in human evolution where technologies begin to compete for functions, but unfortunately the driving force is more and more merely capitalism's demand for continuing profits, not improved technology.
The screen has turned off on my rustic Powerbook 160, so ancient at 10 years old it cost me one dollar on eBay.
I touch the oversized trackball and trigger the myriad of 256,000 pixels to burst back into action, arranging themselves to represent the words of this essay.
The building blocks of LCD's, a curious cholesterol-like substance called liquid crystal, was discovered in 1888 by the Austrian botanist, Friedrich Reinitzer. Liquid crystals have properties of both a solid and liquid, where the molecules tend to maintain their orientation, but with a small amount of heat or electric current, the molecules rearrange like a liquid (though in very predictable & therefore controllable ways). LCD's use a particular type of liquid crystals called twisted nematics (TN). TN's are naturally twisted and can be untwisted to varying degrees by a controlled current.
A simple LCD is composed of a layered system between two sheets of of polarized glass, which is glass created with microthin shutters which cause all light that passes through to vibrate at a certain angle. Between these two glass sheets (polarized at 90o angles to each other) is a coating of TN crystals sandwiched between a common electrode plane made of transparent indium-tin oxide & an electrode in the shape of a what will appear when the LCD is activated. A mirrored surface is behind all of these layers. When not activated (no current to the electrodes), light is polarized by the first glass layer, then twisted 90o with the liquid crystals to the angle of the back plate of polarized glass and finally, reflected off the mirror. If a tiny current is applied to the electrode, it untwists the crystals between the common plane and the shaped electrode. This blocks light from passing through that region and the shape appears black.
With many shaped electrodes, each with a line of current controlled by a microprocessor, you can create all sorts of displays for different devices.
Computer LCD's are much more complex, but still use this same basic system. Two main types of LCD's are used: active matrix and passive matrix. My older Powerbook uses a black & white, passive matrix display. Again, two polarized glass layers are used, called substrates, but this time they are also coated with microthin lines of the transparent conductive indium-tin oxide (one substrate has rows, the other columns). Integrated circuits at the end of each row & column send a charge to a liquid crystal material sandwiched between these two substrates. When a charged row intersects with a grounded column, the liquid crystal untwists at that point and blackens the pixel. The screen is backlit with light from fluorescent tubes which is evenly distributed with a white diffusion panel. By carefully controlling the current sent, the pixel can partially untwist, allowing up to 256 different levels of brightness.
My newer Powerbook has a much more advanced active matrix, color display. It uses thin film transistors (TFT's) which are composed of tiny switching transistors & capacitors. With a matrix of 1024 columns and 768 rows and a red, green & blue sub-pixel at each intersection, the display relies on an enormous number of transistors: 2,359,296 to be exact. If any of these fail, it creates a "bad" or "stuck" pixel on the screen. The active matrix is significantly faster and allows more accurate voltage control over individual pixels, but is also much more expensive.
LCD monitors are becoming more popular for desktop computers as they are small, easy on the eyes, and avoid the radiation bath of cathode ray tubes.
Of course, the majority of technology developments are now digital. As I type this, I am speeding through Tacoma on a stuffy Greyhound bus, my fancier Powerbook squished between myself and the seat ahead of me. The same headphones that earlier delivered In a Silent Way are now powered by the compressed digital hip-hop of Aceyalone. The new major music medium, for better & worse: the MP3.
Throughout my life I've vacillated between a luddite and computer geek. This three-year-old laptop is the most technologically complex device I've ever owned. I usually enjoy utilitizing forgotten technology and limited tools, if anything at all. I'm afraid of the distracting nature of gadgets and cutting-edge technology. People often become addicted to merely collecting & consuming the latest advances in computers, phones, cars & stereos, completely disregarding the necessity of their function.
For example, my grandpa still uses his ancient Commodore 64 to do payroll for his business, Wentz Electronics. Every time I visit, we laugh as he describes his yearly routine of excavating the 1mhz, 8-bit 1979 home computer, along with the clackety daisy chain printer and monstrous floppy-disk drive from the attic. This is a perfect example of archaic technology serving a perfectly useful function.
Even though I am of a ridiculously low income bracket, I still manage to live in a sea of modern electronics and technology.
The US certainly does prove itself a wealthy nation by lending itself to creative leeches on the fringe who exist more-than-comfortably equipped for the urban existence. Refusing to further the technology rat race by driving to Best Buy at the announcement of every advancement in computers, tv, stereos & video is now becoming a quiet form of subversive behavior: a new half-assed manner of rebellion has been born. I add this to my list of not buying meat, riding a bike, conserving resources, and recycling. I'm an unripe Green, bitter at the core.
After being immersed in advanced mathematics and theory for years in school, I realize there is definitely a place for this: LCD's, phonographs and telephones would not exist without the obsessive, highly-specialized, myopic & estranged-from-humanity geeks that created them. Your average microwave-meal munching, Miller drinking, tv-addled schmo wouldn't have his slew of technology fixes and would most likely be stuck plowing a field, hunting squirrel and stripping logs with rocks to build his musty shack.
In researching how just a few devices around me function, I began to respect humans and the advancement of technology much more than when I started. It ceased to be a black & white, oversimplified computer-or-garden dilemma. I realize there's a balance to be struck, which is ever changing & precarious, between simplicity and the utilization of tools.
