Stop reading this article for a second and take a look around you. A majority of your colleagues are probably texting on their cell phones, blasting music on iPods (or an equivalent portable media player), or browsing the web on laptops. Depending on the student, they may even be doing some work on their BlackBerry. Built-in cameras come standard with most of these phones and PDAs, ready to be whipped out just when that elusive Kodak moment arrives. And after a long day of classes, a few of the students here might kick back and watch their favorite flick — on DVD of course.
But have you ever wondered how these things work? Lets take a look at what makes your tech tick.
Cut the Cord
At its core, the cell phone is essentially a specialized radio. Though similar in concept to cordless walkie-talkies and citizens’ band (CB) radio, the cell phone was a groundbreaking solution to a problem posed by these earlier forms of communication. CB radios and walkie-talkies are half duplex, meaning both devices share the same frequency, and, as a result, must take turns sending and receiving. Cell phones, on the other hand, are full duplex, meaning that each device transmits on a different frequency, allowing each device to transmit and receive simultaneously. In addition, cell phones can transmit farther than their counterparts and benefit from multiple base stations that increase their effective range.
Much to the ire of some, cell phones today do much more than just make calls. Even the least sophisticated cell phones on the market today come equipped with simple organizer software and multimedia capabilities for listening to music, viewing mobile web, or sending
Among the endless choices of phones available today, the most advanced of the bunch are known as smart phones. Notorious for their popularity among busy businessman and even some average citizens, smart phones have become both the bane and staple of the “on the go” person. Featuring large screens and full QWERTY keyboards, smart phones blur the line between PDAs and traditional phones. With more sophisticated applications than those on regular cell phones, new apps consistently raise the bar for what consumers expect their phones to be able to do. Although they don’t use full-sized processors, smart phones do have their own operating systems, which tend to be portable versions of popular OSes such as Windows, Mac OSX and Linux, alongside proprietary ones such as Palm’s or RIM’s OS.
Through the Lens
Cameras are, in their simplest form, a lens, body and film element. Light hits the lens (generally glass, although plastic can be used), and is bent in a certain direction depending on the surface of the lens. If the lens bends outward, the light is bent inward towards the middle of the lens; if the lens bends inward, the light is bent outward towards the lens edges. The image is clearest where the light rays converge, known as the focal point. The distance to this point, known as the lens’ focal length, changes in proportion to the roundness of the lens.
The film element “records” the light from the lens. Physical filmstrips use photosensitive chemicals that react when exposed to light. When developed, the film is put in a bath of chemicals that either darken the exposed areas for black and white film or the red, blue and green layers of color film. Digital cameras use Charge Coupled Devices (CCDs) in place of the filmstrips in manual cameras. CCDs typically consist of a grid of capacitors; one for each pixel. The capacitors are charged by the light from the lens. Each row’s charge is shuffled out of the device as the others shift down, repeating until all the rows have been sorted.
Perfect Video Forever
The preferred physical medium for entertainment, and occasionally data transfer, is presently the Digital Versatile Disc. Launched in 1997, the DVD was seen as a derivative of the Compact Disc, which works in the same fundamental way. Both CDs and DVDs are composed of two layers of plastic: a smooth layer on top for protection, and a second layer underneath to contain the data. Data is encoded on the bottom layer as “pits” and “bumps” in a circular track. The disc player reads these by channeling a laser onto the circular track and scanning its reflection for interference. The hits and bumps are read in as 0s and 1s.
DVDs can hold more data than CDs because the lasers in DVD players can be channeled into finer points than the lasers in CD players. While this doesn’t directly add to the capacity of DVDs, it allows manufactures to make circular data tracks that aren’t as wide as those on CDs, and to fit more of them on each disc. In addition, DVDs can have multiple readable layers. The average CD has a capacity of about 700 MB, whereas the average DVD can hold about 4.7 GB. In layman’s terms: the average DVD can hold nearly seven times more data than the average CD.
Despite its usefulness as a medium, DVD is being contested by a new form of digital disc, the Blu-ray disc. The Blu-ray disc uses the same concept and can hold more data for the same reasons a DVD can hold more than a CD; the laser in Blu-ray disc players can be channeled into an even smaller point than that of the DVD’s. However, both DVD and Blu-ray face stiff competition from formats that don’t require a physical medium, such as Apple’s iTunes Music Store.
As phones, cameras and media players grow increasingly more portable and comprehensive, the future is wide open. Though there are no guarantees as to where we’re heading, it’s a pretty good bet that physical media, despite some of its tangible benefits, will fade into the sunset as devices, cramming more and more functions into fewer devices. Beyond that, predicting what paths technology will follow is the stuff of science fiction. For now, we’ll just have to wait and see.