1043: Heading Into The Library Stacks, Finder Secrets, Tasty Waves

The Boston Celtics got their man when they signed Gordon Hayward as a free agent. I have been sneaking off to watch the NBA Summer league games (Grace disapproves) and our newest rookie Jayson Tatum is looking great, too. I see banner #18 in the future!

Meanwhile, Grace and I are planning our annual pilgrimage to Wrigley Field in Chicago. We are celebrating our 50th anniversary this October and with any luck the Cubbies will be there in the post-season but we are heading there for a couple games in August. Anyone know anyone with awesome tickets? We went on one of our first dates at Wrigley Field and we are both fanatical Cubs fans so we go every year. Does anyone remember “Riverview Park”:http://www.defunctparks.com/abandoned/il/chicago-illinois-riverview-amusement-park/ – that is where we had our first date and of course, the park closed forever shortly after that.

Thank you for reading this issue of Kibbles & Bytes!

Your Kibbles & Bytes team,

_Don, Emily & Hadley_

The waves I’m going to talk about here are a little bit different than the “tasty” waves Jeff Spicoli was looking for in Fast Times at Ridgemont High, but they’re still interesting and crucial to modern technology. First though, I need to distinguish what kind of waves I’m talking about. In previous articles, I talked about the electromagnetic spectrum. That spectrum itself is composed of waves too, and we describe electromagnetic radiation waves using wave terminology, such as frequency, amplitude and wavelength.

The waves I want to talk about here though are different. These waves are more accurately described as “electronic signals”. A very basic and simple example of this kind of wave is AC electricity. The voltage varies according to a perfect sine wave up and down, positive to negative. It has a frequency (in the US, 60Hz). It has an amplitude, which is 170V for 120VAC. So this signal is a wave, a sine wave, but it’s not really inherent. We can (and do) create AC electricity with all sorts of frequencies and amplitudes. These waves can also be highly irregular and change over time rapidly.

AC electricity is typically a sine wave because of the rotational methods by which most AC electricity is generated. Any time you have rotation and you’re stretching it over time you’re likely going to see something that resembles a sine wave somewhere along the line. The fact that our normal electricity comes in the form of AC isn’t wasted. We use the sine wave all the time. Induction motors for example use the rising and falling pulses of the wave to “kick” the motor armature into motion. The proper function of the motor depends on the sine wave input. We also use the frequency of the AC signal as a way for certain electronics to keep time.

Sine waves aren’t the only signals we create and use. In fact, while sine waves might be ubiquitous in industrial operations where AC electricity is being used directly, in the consumer world, the square wave dominates. A square wave looks exactly like you’d expect, a square. Unlike the sine wave which gradually increases over time, the square wave goes from one extreme to another almost instantly. Then it holds at some value before dropping back down again. Computers would not function without square waves. A square wave clock signal is like the ultimate orchestral conductor inside of every CPU. Without that signal, the 1s and 0s would be in chaos. Every time the square wave clock signal pulses, one step of the computational cycle can occur. When I built a computer from scratch in college, keeping the clock signal at a reasonable speed was critical.

Another huge use of square waves is in something called PWM (Pulse Width Modulation). PWM can be used to encode a message into a pulsing signal (like a clock signal) and then be transmitted via conventional means. This has applications in telecommunications, though it’s used less today with the advent of digital communications. PWM is also used in photovoltaic charging algorithms. When a battery is depleted, the pulses will be long in duration since the battery needs to be charged. As the battery becomes more charged, the pulses become shorter, thereby delivering less average current to the battery. PWM also has applications in just about any instance where precise motor control is required. Servo motors rely on PWM to function and normal, spinning motors can be adjusted for speed and torque with digital controllers. All CPU fans are controlled by this mechanism. Even my sewing machine relies on PWM. When I press on the foot pedal just a little bit, the motor only spins very slowly. Before PWM, this would’ve been accomplished using a variable resistor. A variable resistor would basically “burn off” excess power in the form of heat. This is wasteful and dangerous. If it got too hot, you could start a fire, or burn your foot. PWM simply sends shorter pulses of power to the motor causing it to spin more slowly. There’s no dangerous “burn off” of excess power. In fact, it’s only using the exact amount of power it needs.

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Square waves aren’t even the end of the story. There are triangle waves, and sawtooth waves and just about any other shape you can imagine (though they might not have any practical use). As an amateur composer of electronic music, the square, triangle and sawtooth waves are the bread and butter of synthesized sounds.

I’m not sure if I’ve changed Jeff Spicoli’s mind on these waves, but hopefully others have found this explanation of waves and signals to be interesting.

I remember way back when, that Grace and I would go to the Chicago Public library to “do our homework”. When we actually did some homework the reference section was my favorite. That and looking at the huge microfiche library of old copies of the Chicago Tribune.

Did you know that Apple hid a huge reference library in your Mac?

You’re probably used to Mac apps using red underlines to mark misspelled words, but did you know that macOS has long included a fully-featured Dictionary app as well? It provides quick access to definitions and synonyms in the New Oxford American Dictionary and the Oxford American Writer’s Thesaurus, along with definitions of Apple-specific words like AppleCare and MacTCP. But that’s far from all it can do.

First, let’s make sure we’re all on the same page. Launch the Dictionary app from your Applications folder and then type a word or phrase into the Search field. As you type, Dictionary starts looking up words that match what you’ve typed so far–you don’t even have to press Return. If more than one word matches what you’ve typed, click the desired word in the sidebar.

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Notice the lozenges below the toolbar, representing the references that Dictionary can consult, and no, your eyes aren’t deceiving you–Dictionary can look things up in Wikipedia if your Mac has an Internet connection. In short, Dictionary gives you instant access to a dictionary, a thesaurus, and an encyclopedia containing over 5.4 million articles in English alone! You can click a reference’s lozenge to limit your search, or select All to scan all of them.

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If you want to look up words in another language, or even just British English, Dictionary has you covered, with a long list of other reference works. Choose Dictionary > Preferences and select those you’d like to use. You can drag the selected entries into the order you want their lozenges to appear below the toolbar.

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Once you’re in a definition, note that you can copy text for use in other apps–always helpful when wading into grammar and usage arguments on the Internet. More generally, you can click any word in Dictionary’s main pane to look it up instantly. If dictionaries had been this much fun in school, we’d have larger vocabularies! Use the Back and Forward arrow buttons to navigate among your recently looked-up words.

As helpful as the Dictionary app is, you probably don’t want to leave it running all the time. Happily, Apple has provided quite a few shortcut methods for looking up words:

* Command-Space to invoke Spotlight, and enter your search term.

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* Select a word, and then choose AppName > Services > Look Up in Dictionary to launch Dictionary and search for that word. This trick should work in most apps, but won’t work in all. If the Look Up in Dictionary command doesn’t appear, make sure it’s enabled in System Preferences > Keyboard > Shortcuts > Services, in the Searching category.

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* Last but best, hover over a word or phrase with the cursor and either press Command-Control-D or Control-click the word and choose Look Up “word.” If the app supports it, macOS displays a popover with the definition or Wikipedia article. If you have a trackpad, you can also do a force-click or three-finger tap on the selected word–make sure the “Look up & data detectors” checkbox is selected in System Preferences > Trackpad > Point & Click.

Now that you know how to take full advantage of the reference library that Apple has built into macOS, it’s time to get in touch with your inner logophile (feel free to look that one up).