Introduction
Much of life consists of the transfer of information. The higher layers on Maslow’s pyramid of needs clearly require the transfer of information, but even the lower layer needs of food, water, shelter, etc., also involve information exchange. It is tempting to think of a rugged individualist making his way in the world on his own creativity, cleverness and strength. But before you go too far down that road, rewind the tape to the birth of our rugged hero. He had a mother and father, because that’s just the way it works, and probably siblings. So there was a family. And they had parents, so there was an extended family. It doesn’t take much imagination to extend our example family to create a community. And one of the benefits of a community is the sharing of information. “Food there.” “Water here.” “That will make you sick.” “This will make you feel better.”
The word “signals” can be helpful in describing the transfer of information. Signals are often visual or audible, but they could be related to any action detectable by the senses. The taste of salt coating a piece of meat can serve as a signal that the meat has been preserved. Signals are often immediate (“real-time”), such as a wave or a shout, but they can also be more permanent, such as a notched stick showing a path, or a stack of rocks indicating a property boundary.
Our world is full of signals, not just durable visible objects like billboards and other signs, but electronic signals such as phone calls, e-mail, radio, television, as well as visual signals (traffic lights and school crossing guards) and audible ones, too. There are train whistles, door bells, car horns, singing birthday cards, fire alarms, barking dogs, seat-belt buzzers, job performance assessments, and microwave oven beeps, just to name an eclectic few.
While most signals leave their source in a relatively pure form, few signals reach their destination in that same form. The word “noise” is often used to refer to the difference between the original signal and the received signal. Let’s use a radio broadcast as an example. Suppose you are in the room where the radio broadcaster is speaking, and you have the ability to hear and remember the sound of her voice precisely. Even better, you have a machine which can depict her voice in some visual fashion on a piece of paper – every nuance, every frequency, every phoneme, every word.
Now suppose you are in your home listening to this same broadcaster over the radio. The sound is somewhat different than you heard in the studio, having been affected by many factors. To name just a few, the microphone picking up her voice converts the sound vibrations to an electrical signal, and the electrical signal is converted to a radio broadcast frequency. Your radio receives the broadcasted signal, plus lots of other radio signals and frequencies, converts them to the range your ears can hear, then sends the electrical signal through a speaker which converts it to moving air. Finally the moving air impacts your ear drums, which transmit the sound impulses to your brain, where you interpret them.
Each of these detection and conversion steps is imperfect, and it changes the signal in some way. Each medium through which the signal flows, whether the air in the studio, the radio station’s copper wires and circuits, the humidified air between the radio station and your house, the wires in your radio, and the air in your room, they all effect the signal in some way, reducing certain frequencies, adding other signals, modifying not only the original signal, but each of the previously modified versions.
So imagine you once again document the broadcaster’s sound precisely on your machine, this time in your home. If you could measure the differences between the original signal and the signal you hear, those differences are what I mean by “noise.” Some types of noise introduced in an electrically amplified audio signal may consist of background hum, crackle, distortion, wow, flutter, phase shift, phase cancellation, all different types of noise, many of which have also, oddly enough, become special effects for electric guitars. Go figure.
Now, if you’ve heard how digital signaling is better than analog signaling, you might be thinking that there is no “noise” associated with digital signaling. I’m sorry to be the one who has to break it to you, but that is incorrect. The process of analog-to-digital conversion always introduces inaccuracies, not to mention time delays, which are, in fact, another form of noise, although one that is often acceptable. Unless you are trying to sound intelligent over a satellite phone link.
One last technical comment – the ratio of signal to noise is a good measure of the quality of an information system. A higher ratio means that the systems transmitting the signal are better, more accurate, or “quieter.”
Good grief this has been a painfully long introduction. The whole purpose has been to introduce the notions of signal and noise, for the purpose of making a rather simple point. There are probably easier ways to make this point, but that’s just the way my peculiar brain works.
The Point
And the point I’m trying to make? Most of the signals we receive in life include noise, some more than others. If the noise is sufficiently large, it begins to affect our ability to process the actual signal. It distracts us, disturbs us, slows down our thinking. It wastes our time, just like an error-correcting digital receiver, that must stop and recalculate the received signal to determine mathematically what the original signal was supposed to be.
What are some examples of noise in modern communication? Of course, that is a matter of opinion, and a matter of what the receiver considers to be the desired signal. For me, examples of noise include advertising, unnecessary graphical elements, and misleading content. My Internet tastes tend toward sites for which I’ve already paid, such as NOAA for weather, APOD for my astronomical photos, NPR for news, and georgia-navigator for local traffic, largely because those sites don’t besiege me with advertising. I use an e-mail client instead of web mail because it is clean and direct, rather than cluttered and, well, noisy. Whenever possible, I opt for the paid version of an application, rather than the advertising-supported version. I remove distracting backgrounds whenever possible, and make my chart lines thin. I use labeled boxes rather than clip art, unless the clip art conveys important information. And, despite the absurd length of this posting, I try to avoid words which don’t carry the reader swiftly and efficiently toward my writing goal.
Once you are aware of the difference between signal and noise, you can begin to detect the difference, and to make your own choices for information transfer. Happy hunting!