Presto Electro

I found my camera in my underwear drawer the other day. It had been missing for kinda a while, so I couldn't really remember what the last thing I photographed was. I fired it up, and was greeted with the gleaming, smiling face of this guy:

As you can probably imagine, this is not a face that is easy to forget… I knew I had seen it before, but I couldn't quite place it. So I skipped to the next picture:

NOW I had it, the Flaming Lips show!!! I forgot I brought my camera along for the show and promptly buried it in socks when I got home. Finding these pictures made me start to reminisce about the Flaming Lips show… It was amazing. The music was great. The surrounding crowd was awesome. And it cost exactly zero dollars.

…And this weekend, Denton did it AGAIN! But bigger, better, and for three days straight!!!

Last weekend was Jazzfest. Jazzfest is a three-day festival celebrating the tremendous amount of art and jazz in Denton and the surrounding area. It was epic. 200,000 people descended upon Quakertown Park to enjoy hundreds of artists of all sorts of media. You could spend a whole day just wandering around, checking out all of the paintings, sculptures, drawings and the like. I almost did on Sunday! I spent a good hour taking in the sights, but I had to get back to catch the UNT African Drumming and Dance Ensemble. (African Music is one of the few genres that can compete with Math Rock when it comes to poly-rhythms, so there is no way I was going to miss UNT's ADDE)

On the Friday before, I spent almost all of my time on the UNT Showcase Stage. This was where all of the UNT bands played, and I really only wanted to see UNT bands anyway. We're a legendary jazz school! It would be almost sacrilegious to go elsewhere for awesome jazz. My favorite band of the night was definitely the UNT Latin Jazz Ensemble. These guys were so awesome that loads of people hopped up out of their seats to dance to the ridiculously catchy Cuban beats.

And once again, The City of Denton and the myriad Jazzfest sponsors aimed it right at the typical student budget: 7 Stages, over 2,200 performers (Including headliners like Chick Corea, Brave Combo, Jimmie Vaughn and The 1 O'clock Lab Band) and countless visual artists of all kinds for exactly zero dollars. I love this city

As many of you know, I am a member of all sorts of environmentally friendly, earth-conscious groups: Slow Food, Engineers Without Borders, and The North Texas Energy and Environment Club are the most active of the bunch. And they are all pretty big fans of the same planet. Ours. Earth.

So for Earth Week I was a busy, busy boy. I was routinely triple-booked, and everything I was invited to was EXTREMELY COOL! It was not easy picking and choosing where to be at any given time this week. Check out my extremely complicated schedule for earth week:

(I nearest-neighbor resized it on purpose for censoring purposes because I am a photoshop PRO)

Upon closer inspection, I was actually quadruple-booked in some places. Sheesh. And I didn't even get involved (on an organizational level) with the bulk of the earth day celebrations! Check out this list of Earth Day Goings-On that I had nothing to do with on the main campus:

There were also a ton of events at Discovery Park, too. But I can't find hide nor hair of the poster for those events. On Earth Day proper (April 22^nd) there was a totally awesome Earth Fest at Discovery Park. It was at lunch time, and the main campus' Earth Fest was at dinner time, so if you really wanted to (and believe me I wanted to) you could've gone to both, and ate like a KING all day. I was (understandably, I hope) pretty beat by Thursday, so I went home and indulged in a nap during the main-campus earth-fest. But I did go to the Discover Park Earth Fest!!! Here is photographic proof:

Don't worry, I haven't joined the Federal Service they just had totally rad out-door laser tag at Earth Fest! They also fed us some excellent barbeque, and snow cones and ice cream. And while we were eating in the picnic area (which is in FULL BLOOM this spring, by the way) there was even a band providing some nice background music. Very classy. I am sure more pictures of the event will surface, so stay tuned! Hopefully there won't be too many more of me running around with a lasergun like some kind of lunatic…

Denton is a city with a lot of unusual sights. From the day-glo orange messenger trucks of Frenchy's Lawn & Tree Services to the immaculately-restored Denton County Courthouse:
But when I first moved up here, I was always the most struck by the façade of Recycled. On paper, a pink building with lavender trim sounds like something a Disney princess would live in, but in real life it really works out great!
This is largely thanks to the fact that Recycled is actually a recycled Opera House that was built in 1899. To add even more recycle-y-ness, the Opera House was built out of the bricks from the Denton County Courthouse that was condemned in the 1870’s. There are bricks in that building that are upwards of 150 years old!

The outside is brilliant, but the inside is where Recycled really shines. The place is filled with an absolute labyrinth of shelves. You’ve really got to see it to understand, but they have a photo gallery on their website that hints at the layout of the place.
Once you get over the novelty of walking around a human-sized mouse-maze, the substance starts to sink in. Every shelf, every wall, is covered in REALLY COOL BOOKS! Recycled has sections on every subject imaginable. Art books, sheet music, science books, literature, nonfiction, metaphysics, yachting, farm upkeep, public records, poetry, picture books… the list goes on. If you want a book on some vague topic, Recycled almost certainly has a section for that.

If you’re not much of a reader, there is still plenty of awesome to be had. Recycled also boasts really big CD and record collections. I’ve found a lot of really great gently-used CDs here, and it is the only record store I know of that has a Local Denton Music section.

There’s also a Jazz section that is bigger than any Jazz section I have ever seen in my life. There’s almost more Jazz than pop at Recycled, and that warms the cockles of my heart.

In my last article I mentioned Denton’s uncanny ability to have all of that small-town flavor without that bitter small-town aftertaste. Today I’d like to upgrade all the adjectives in that sentence and talk about the metropolis-sized charms of modern-day Denton.

When I was living in the suburbs, north of Dallas, there was never anything nearby to do. If a band came to the metroplex, it was always a minimum of half an hour away, and parking was always a disaster (and expensive). In the end it usually took more time to GO to the show than it actually did to see it in the first place. This resulted in me and my friends seeing a lot less shows than we wanted to.

Everything changed when I moved to actual, real, down-town Dallas. Bands would come to the metroplex and I could WALK to the shows! I was two minutes away from almost every single venue. I saw a TON of shows. My weekend plans almost always involved a trip to one of the many Dallas venues because hey, why not?

The trouble is, down-town Dallas is also a crime-ridden and scary disaster of a place sometimes. My car got broken into a LOT while I was down there, and I was constantly exposed to crime and vagrants and all sorts of endemic big-city problems. I figured that was just how cities were. You take the good with the bad, and try not to notice the fact that your cheap apartment isn’t so cheap when you have to replace your driver’s side window every three months.

But then I moved to Denton! There is ALWAYS a cool band playing out here, and there are a million different places they can do it. There are traditional venues peppered throughout the city (mostly near the square though) and then there are house shows on top of all of that.

Last Saturday Camera Obscura came to Hailey’s and played an amazing show. It was their first time to come to Denton, and they had nothing but great things to say about it. (Of particular note was their praise of Denton’s own Old Fashioned Ice Cream Shoppe, Beth Marie’s.) My facebook was exploding with comments leading up to it because all of my friends spent the money they were saving for summer on show-tickets--Irresponsible! But it was so worth it.

My favorite thing about Denton is its ability to be a small town and nothing like a small town at the same time. This Saturday the planets aligned just so and the best parts of both worlds shined through simultaneously. Today I'll cover the small town bit, because it's my favorite.

I've always been stuck in either a big gross city or a totally unimpressive suburbia, so the small townish bits of Denton are a constant source of joy to me. On one of the first days after I moved here, I managed to "strand" myself on the main campus after the buses had stopped running to Discovery Park.* (See Footnote!) I was really bummed about it for about two minutes, and then I realized that the entirety of Denton is about 4 miles across, and a half-hour walk can get you pretty much anywhere in the city. It was a beautiful night, and the walk home was actually quite pleasant, if a little long. The little things like that are an unending source of novelty for me. Small towns are so much more convenient than big ones! Where I grew up, if I somehow wound up (assuming-I-was-) stranded at my old high school, it would have been a long, LONG walk along an extremely busy highway.

At this point I think we can all agree that yesterday's amplifier was pretty much terrible. It had way too much signal distortion and not enough common sense. Now that I've learned what I did wrong, I can apply this knowledge to future projects. Or current projects, as the case may be.

In Analog Systems Design last week I built a PROPER amplifier. As it turns out, a real amplifier has multiple stages designed to preserve and filter the audio signal in the most controllable way possible. Here's a flowchart for the one I built last week:

As you can see, a proper audio amplifier actually contains two amplifiers. And a few other components in between that I'll get in to a little later. To analyze this circuit, let's start from the end and work backwards:

• The Power Amplifier: This is very similar to the circuit I built in the last update. It takes a voltage signal and makes it louder. Nothing too fancy. A potentiometer attached to the feedback loop of this amplifier serves as a volume control knob. The input voltage comes from…
  
• The Equalizer: This summing amplifier takes the signals from each of the audio filters and combines them all into one single signal. Usually the gain on this amplifier is 1, or unity, indicating that it does not amplify or dampen the signals. It only combines them. Depending on the number of filters in the amplifier, the equalizer could have any number of knobs to dampen each frequency range. The frequency ranges are determined by…
  
• The Audio Filters: Low-Pass, High Pass, and Band-Pass filters can be employed in this section to split the sound in to bass, treble and mid-level chunks. My personal amplifier was designed to isolate bass notes with a (low-pass filter) and high notes (with a high-pass filter). A third, unmodified signal, was also sent to the equalizer for mixing purposes. The high- and low-pass filters only function correctly when the voltage input is large enough to interact noticeably with the capacitors. Most audio signals are not loud enough to do this on their own, so you've got to use…
  
• The Preamp: This amplifier doesn't have quite as much power or gain as the power amp. Its job is to take the tiny AC signal produced by the audio device, and amplify it before it gets sent to the filters. Some audio devices (like Carbon Microphones, for example) need a DC current in order to produce any kind of signal at all, but sending DC into this preamp would be bad-news-bears. High-DC currents could saturate the preamp very easily, which would result in a totally gross sound. So we need to remove the DC but preserve the AC with…
  
• The Coupler: Fortunately for all of us, DC voltage can be thought of as an EXTREMELY low frequency AC voltage. Imagine it as an alternating current signal with a period of ∞ and a frequency of 1/∞ (a.k.a. zero). The coupler is just a high-pass filter that passes almost every frequency except for extremely low ones. My coupler let every single frequency in the range of normal human hearing pass right on through.
  

This amplifier actually sounds pretty good! For testing purposes, we had to output the signal through a really small, tinny speaker that was about an inch in diameter, but it was still a lot nicer sounding than the mess I made with that op-amp so many years ago!

I apologize for the slow updates lately. This week was basically the perfect storm of exams and major projects. On the plus side, the exams all went great and I can add "Building a complete amplifier" (including pre-amp, audio filters, equalization, panning and power amplification) to my resume. And list of bragging rights.

As it turns out, amplifiers are a lot more complicated than I ever imagined. I tried to build one once when I was in high school, and it didn't turn out so great. For starters, the design centered around a 50 cent op-amp from radio-shack that really shouldn't ever be used anywhere near any sort of audio signal processing. I googled around and sorta half-figured-out that I could use an inverting amplifier configuration to amplify voltage signals.

So I did just that! I wired it up with a few resistors I took off of an old, broken VCR (of which there we about half a dozen to choose from in my room at the time) and the op-amp, and then I powered the whole mess with a wall-wart AC-to-DC adapter. I plugged my terrible guitar into this abomination of a circuit, and somehow nothing caught on fire. I plugged a pair of headphones into what I perceived to be the output, and out came the LOUDEST, most FIERCELY DISTORTED guitar sound I had ever heard. It was awesome.

Sure, I had completely failed in adequately amplifying the signal of my guitar, but instead I created a box that made my Squier sound like some kind of hideous beast out of hell. The trouble is, I couldn't really spend much time listening to it because it shredded my headphones pretty quickly. So where did I go wrong?

I've already outlined a handful of problems, but some of them were only implied. As it turns out, the source of the distortion (ignoring the distortion caused by my poor, rupturing headphones) was the AC adapter. Operational Amplifiers are supposed to have a bi-polar power supply: One positive voltage, and one negative voltage. My adapter was only giving it a +9 and a +0.

So the output couldn't give me any voltage at all when it was supposed to be putting out negative voltage. This brought out some weird clipping that REALLY got ugly if you played more than one note at the same time. Additionally, my headphones were linking Vout with ground, with only minimal resistance. In order for Vout to provide the appropriate amount of feedback current across Rf, the amp had to make Vout absurdly high. This elevated voltage made the incoming current cancel with the Vout/Rf current, but it also made Vout way louder than anyone could ever want.

I've still got that circuit bread-boarded in a box somewhere. I ought to get it out and see if I can fix it sometime. I've still got that old Squier… (because you can't even GIVE those things away…)

I really thought it wasn't going to work out. It seemed too good to be true, but the Flaming Lips show actually, really happened, and it was actually totally awesome. For Stardeath and The White Dwarfs, and Midlake, I mostly wandered the fairgrounds taking in the sights and sounds. I also helped myself to an enormous barbequed turkey leg. I haven't had one of those since I last visited Scarborough Faire, and I devoured it like it was the first meal I'd had in weeks.

Eventually it started getting a little chilly, and The Flaming Lips started setting up. As it turns out, the huge ferris-wheel looking light-rack behind the stage contained a giant LED screen. I realized this when the seemingly empty space spontaneously turned into a huge image that looked like a test pattern from the dark side of the moon.

Once they finished setting up, the show began and Wayne Coyne ventured out into the crowd in his trademark space bubble as orange and yellow confetti and humongous balloons flew out over the rest of the audience. It was a pretty amazing start to a show that will definitely go down in history as one of Denton's most legendary.

The set list included all of the crowd pleasers, Yoshimi, The Yeah Yeah Yeah Song, Do You Realize, and Waiting for Superman. There was also a lot of really cool, really weird new stuff from their newer albums, too. Here's the full setlist:

1. Intro

2. Worm Mountain

3. Silver Trembling Hands

4. Yeah Yeah Yeah Song

5. In the Morning of the Magicians

6. Watching the Planets (acoustic version)

7. Yoshimi Battles the Pink Robots pt. 1

8. Wating for A Superman

9. See The Leaves

10. Convinced of the Hex

11. Do You Realize

Because Wayne Coyne and the rest of the band are awesome dudes, you can listen to most of these songs on Official Flaming Lips Youtube! You will just have to use your imagination for the rest. Or buy their latest CD.

After the show was over, the good people of Denton helped themselves to a few more turkey legs and filed out peacefully and quietly back to their homes. The concert was a total success and I can't believe it all happened about 200 yards behind the Kroger I buy groceries at every Sunday. Small world!

PS - If you'd like to know more about the show, and the rest of NX35, The NT Daily Blog has a great write-up with awesome pictures.

This spring break was one for the record books. As many of you may know, last weekend was Denton's own Music Conference, NX35. From Thursday, March 11^th, to Sunday, March 15^th, musicians celebrated and demonstrated the staggering amount of musical talent and know-how Denton has to offer.

The Schedule is already impressive enough to boast about, but that is only just the beginning! The plethora of shows and panels officially sponsored by NX35 only served to get the ball rolling, and the good people of Denton really grabbed on to the spirit of the event and made something amazing out of it.

Denton was filled-to-bursting with celebratory parties, performances and picnics. My personal start to the NX35 festivities was an awesome house-show/picnic/chili cook-off with live screen printing. I'm not joking. The artists in this town don't mess around!

The event took place at one of the many great houses in the Oak-Hickory Historic District with a huge yard. The owners put on a free show with nine awesome local bands right across the street from the campus. And they provided free brownies and drinks, three local artists, and live screen printing. I'm not sure why, but screen printing always seems to make its way into these events. There was even a screen printing going on at the Free Flaming Lips Show.

Which brings me to the coolest part of NX35 2010: On Saturday, Midlake and The Flaming Lips played an AMAZING and FREE show at The North Texas Fairgrounds!

I just happen to live a stone's-throw away from the fairgrounds, so my friends and I all met at my house and walked over to the fairgrounds. We got there about 15 minutes after the gates opened, and walked right in. There wasn't even a line! I convinced everyone to leave super early to beat the crowds and I pretty much felt like a jerk when there was no line at all.

Fortunately that feeling didn't last long, because it was an absolutely gorgeous day, and the fairgrounds were full of amazing people. The sun was out, it was clear and warm but not TOO warm, with a nice breeze, and this show was basically the social gathering of the year!

Interesting people were all over the fairgrounds, but my favorite of the bunch was a roving band of bohemian musicians. I have no idea what band (if any) they were a part of, but one of the largest groups on the fairgrounds was a big circle of people banging on drums and playing instruments together out in the middle of the field. They produced a really beautiful racket that was reminiscent of Animal Collective, unplugged, and it was amazing.

They created the perfect soundtrack for a fantastic gathering on a fantastic day in this fantastic city of ours. And it only got better, from there! I'm afraid I've run out of room, but check out my next update for the rundown on the actual performances.

I know I spend too much time raving about infographics. I promise that is not what this update is about… but I am going to lead off with this one. It's an interactive graph that plots companies based on their reputation and performance with regards to their environmental impact. There are a lot of surprises—particularly Whole Foods being worse for the environment than Ebay (what!?)—but I was most amazed by the mention (and performance) of Green Mountain Coffee Roasters. (Hint: You can filter the infographic to "food & beverages" to make them a little easier to find.)

If you've ever visited Discovery Park, you might remember these guys: they're the coffee shop right outside of the cafeteria. They also have a bigger shop on the main campus in the University Union. It's actually a little bit strange for them to be seen this far south. I can't prove this conclusively, but according to Google's Map and the Company Website, UNT's coffee shop might be the only time Green Mountain ever dips its toe below the Mason-Dixon!

What makes them so green, anyway?

I've always known they were purveyors of organic coffee, because the nameplates on every pot of coffee say so, but I didn't know that the coffee is also 100% Fair Trade as well. On top of that, Green Mountain's award-winning ecotainer™ coffee cups are completely biodegradable because the inside is lined with a biopolymer instead of the "traditional" polyethylene.

In spite of all of this, the coffee still somehow costs about the same as any other cup of coffee I've ever bought. I have no idea how this is possible. They also find the time (and funds) to donate hundreds of thousands of dollars to coffee-growing communities all over the world. That's probably why CRO ranked them #1 in the 100 Best Corporate Citizens for 2006
and 2007.

Suddenly I don't feel quite so guilty about buying a raspberry scone and a cup of their delicious Wild Mountain Blueberry Coffee every morning!

I may or may not have mentioned this before, but I write all of my updates on a little, tiny netbook. Its screen is about ten inches across, and its resolution is a teensy 1024 by 600. It's small. Very small. Earlier today I read an article on this very screen that suddenly made it feel a whole lot smaller…

The article was about the UNT Research and Visualization Environment (RAVE). RAVE provides powerful and HUMONGOUS computing resources to faculty and students to help them visualize and understand the impossibly large amounts of data computers are capable of coagulating these days.

Before today, I thought the 24" wide-screen monitors in the GAB Lab were preposterously large, but this array of monitors (pictured above) could adequately display the contents of almost 70 screens the size of my laptop, and the cluster attached to them guarantees they won't even stutter when they do it!

Writing an article on a tiny screen is not so bad, but when I was trying to design a box diagram the other day (for a project in Digital Systems Design) I would have done almost anything for 40 megapixels to move around in…

This article also answered a question I've been wondering about for some time. The walls at UNT are papered with huge posters summarizing undergrad and graduate student projects, and I never knew how they managed to print something so enormous. Now that I know about the visualization environment, I'm pretty sure that beastly printers like this one are responsible:

Now I know, if I ever need to tackle a problem that is making my laptop burst at the seams, I've got all sorts of gigantic resources available to me at UNT.

The other day I mentioned watching a thought-provoking documentary in the media library on campus. The movie was called Flow, and it was (mostly) about the water supply in developing areas. The gist is, healthy people require healthy water. There are a lot of ways to provide this, but my personal favorite was Ashok Gadgil's ultraviolet water-sterilizing contraption.

Bacteria is extremely susceptible to ultraviolet light, so exposing incoming water to a UV light is an easy and efficient way to disinfect water. Many of the diseases common to developing countries begin with infected water supplies, so this simple contraption has made a humongous difference in the way people live. Ultraviolet Germicidal Irradiation is not a new concept to the modern world, but it is a revolutionary one in developing countries.

This sort of application of technology really appeals to me, so when I heard about "Engineers without Borders" I was very excited. You might have heard about "Doctors without Borders" (or "Médecins Sans Frontières" if you're from outside the states). "Doctors without Borders" is an organization that sends doctors all over the world to help developing countries with medicine, nutrition and sanitation.

"Engineers without Borders" is a newer idea. There is no official, national group (yet!), but the intentions are very similar. The University of North Texas' Engineers without Borders group met for the first time just last week, and discussed all sorts of ideas for improving the world around us. There are a lot of opportunities nearby and abroad that could use our help. If the fundraising goes well, an adventure in Mexico might be in our future!

A couple posts ago I talked about "clipping". More specifically I talked about how cool it sounded, and how hard it was to find an audio representation of it. Well guess what? I had some free time this evening and I put together a couple of mp3s for your education and benefit:

Sine Waves

I'll be honest with you: Sine waves are boring as heck to listen to. They don't have any harmonics at all, so the sound they make is really quite uninteresting. For the purposes of this experiment, I've synthesized an F Major chord to give this mp3 at least a little interest. The waveform below is a visual summary of the component parts of the chord. You may listen to them by clicking on the picture!

Even with the harmonizing it is still pretty tough to hear. Below, I've doubled the frequency (raised it an octave) so it is a lot easier to hear:

Clipped Sine Waves

Thank you for enduring the sine waves. Here comes the good part! This clipped sine wave sounds awesome, and I am sure you can imagine the kind of impact some careful clipping could lend to a guitar sound. PLEASE BEWARE!!! The clipped wave is MUCH easier to hear! If you turned your speakers/headphones up for the sine waves, turn 'em back down!

Visually, the clipped wave doesn't look like much of anything. It certainly doesn't seem like it would be very much more interesting than the others. But our ears process sound waves in a way that interprets the "corners" of the clipped wave as a bunch of sounds interfering with each other.

If you play these mp3s in anything with a graphic equalizer, you can see a visual representation of this phenomenon: The clipped wave show up over a much higher range of frequencies than the sine wave does. Here are some extremely scientific animated GIFs for the mp3-player impaired:

I've been seeing a lot of movies lately. I'm not doing it on purpose, but sometimes every single person I know wants me to go see a movie with them, and I never turn down a trip to the movies. Last week I saw a movie almost every single weekday. Fortunately we had a lot of theaters to choose from, so I didn't have to go to the same one over and over again.

Tuesday Night: The Wolfman @ Denton Movie Tavern

On Tuesday night I saw The Wolfman at the Denton Movie Tavern. The movie was hilariously terrible and/or terribly hilarious, but you could probably guess that from the title. The Movie Tavern was great, though. This was my first ever trip to the Movie Tavern, but I've wanted to visit for ages. I'm a big fan of food with my movies, and theater/restaurants (Theatrestaurants?) are pretty much the best way to combine the two. (I am not a big fan of after dinnermovie dishwashing.) I didn't have any food this time (I had a big dinner okay), but the Movie Tavern had a great menu, and a surprisingly cool lobby area. The real advantage to the Denton Movie Tavern is the LUXURIOUS foot-room in-theater. Each row is separated by a long thin dining table, so its almost impossible to accidentally kick the person in front of you in the head/arms.

Wednesday Night: Flow @ The Media Library

The University of North Texas campus isn't a theater in the conventional sense, but it is nevertheless a great place to catch a cool movie or two. A cursory glance at announce.unt.edu reveals everything from thought-provoking documentaries to totally brainless blockbusters. If you live up here, I recommend subscribing to the Arts and Entertainment RSS Feed to remain abreast of the entertainingest bits of UNT. Personally, I'm subscribed to the omni feed that lists every single announcement from everywhere on campus because I love always having something to do.

Thursday Night: Crazy Heart @ Cinemark 14

Ah, Thursday nights at the Cinemark 14… The Cinemark is a totally regular, normal theater. It's clean and nice and the seats are comfy, and everything is well maintained. It doesn't have quite as much personality as the other places, but it does have plenty of screens. It's also a tiny bit out of town. It's only 5 miles from the square, but five miles is a long way when everything you could possibly want is less than three miles away in Denton. On Thursday nights, though, it is definitely worth the drive. Thursday tickets for students are only $3.50! Nice!!! The movie wasn't particularly amazing or anything, but I've only myself to blame for that. I've already seen all the good ones.

Electronics I is a very mysterious title for a class. When I enrolled in it last semester I didn't have any idea what to expect. I could have looked up the course summary in the online course catalog, but I like surprises. I also completely forgot about the course summaries in the catalog until just now. Yeah.

Anyway, I'm taking Electronics I this semester, and the second unit is all about Diodes. The first unit was Op-Amps-- fascinating, but probably too complex to summarize in a single blog. Diodes, on the other hand can be represented by this very simplified model:

The "Ideal Diode" works like a little switch. It turns "Off" when the current tries to flow one way, and turns "On" when it goes the other direction. It's like a turnstile or a one-way street, except instead of people or cars, it organizes electrons. This behavior allows for all sorts of clever manipulation of current. Rectification was the focus of last week's class, but diodes can also be used for things like diode logic and audio manipulation.

Whenever an electronic component can be used to manipulate AC signals, I start imagining what sort of impact these things could have on audio signals. And I'm definitely not the only one. Non-linear components are golden when it comes to distortion!

Here is a great example of diode use in action. This circuit takes advantage of the fact that real (non-ideal) diodes need a little kick-start before they flip "on". If you apply more than zero, but less than (usually) .7 volts to an LED, it stays off. If you go over that threshold, if flips "on". In this case, it flips on and connects the guitar signal to ground, and chops off the top of the peak of the signal.

I've found approximately a million articles about clipping and distortion, but NONE of them have sound!!! I think I'm going to have to bring a guitar into the lab tomorrow…

I love a good infographic. They look cool, they're educational, and they're huge time savers. A well designed infographic can illustrate a huge wealth of information at a glance. I've always felt that infographics were pretty neat, but I haven't had a good reason to mention them. Until now.

This semester, I'm taking Professional Presentations. The first chapter of the book has a lot of information about the history of presentations and graphics and colors and everything, but it also has some SWEET infographics. Check out this one:

If you are ever confronted with an upset dog, just turn to page 50 of Edward Tufte's The Visual Display of Quantitative Information, and use this handy graph to figure out how the dog REALLY feels!

There are plenty of excellent charts and graphs in this book, but the examples of what NOT to do are so much more interesting than the proper ones. As a case in point, check out this graph of inclinations of planetary orbits from the Middle Ages:

Back then the sun bounced up and down at random, apparently! In the artist's defense, though, this is the oldest known example of a time-dependent plot. It didn't really catch on. The next example wasn't seen until 800 years later.

These days, we are SURROUNDED by information. A huge amount of data can be construed as relevant to any given topic, and it is easy to come away with even less of an understanding than you started with.

It takes a special kind of smarts to turn this intractable bulk of information into an image that is both easy-to-understand and easy-on-the-eyes.

The University of North Texas has a TON of computer labs. The General Access Computer Labs (GACL) system has 14 labs peppered throughout the campus, and that's not even including the myriad of labs tailored to less-than-general access. Every lab comes with Microsoft Office 2007, Photoshop, and a selection of web browsers.

But most labs also come with a little extra. The Technical Communication department has a Technical Communications Lab with software that is particularly great for technical writing, and the College of Music has its own lab with software more appropriate for enhancing the ability of any musician. The list goes on and on, but if you're wondering about a particular program, I recommend consulting this page.

The Electrical Engineering Department has a boatload of specialized labs. In Digital Systems Design, my computer station sits next to a tall stack of analytical equipment and power/function generators. The computer itself is loaded with all kinds of professional software for digital design, and Xilinx is the program that I have (thus far) used the most.

In Digital Systems Design, most of the projects are programmed on to Field-programmable gate arrays (FPGAs). Prototyping digital circuits onto a breadboard is really fun, and it is a great way to realize schematics, but it can be a HUGE PAIN to troubleshoot. If your circuit doesn't work on the fist go, every single wire could be a potential point of failure, and figuring out where to test first is often puzzling.

With FPGAs, you can skip the messy wiring bit. Once you've worked out the behaviors of your project, you just need to translate it to VHDL code. Writing the code for it is fairly straight-forward, and Xilinx helps out along the way with syntax checking and simulation. You can even test your design with a "test-bench" script that will apply virtual inputs to your simulated system, and then display the outputs. Test-benching is a difficult concept to explain, and I apologize for that last sentence. Here is a picture of the results from my first test-bench of the year:

The two inputs, 'a' and 'b', were provided by my test-bench script. The resulting output is 'f'. Can you guess what this circuit does? Email me if you want a hint! :)

My favorite living band, The Fiery Furnaces, came to Dallas last night! Although it was a Wednesday, I still found time to make the drive down. It was an AWESOME show, of course (And they're playing in Austin tonight, and Houston tomorrow, if you'd like to see for yourself!) and it was definitely worth the half-hour drive. The odd thing was, even though I spent most of the evening in Dallas, little things kept reminding me of good ol' Denton.

I have a tendency to mistake doors-open-at times for band-goes-on-at times pretty regularly. Unless I've brought someone more sensible along, I usually show up to shows way earlier than I should. Last night was no exception. I showed up to The Lounge at 7:55pm and handed the bouncer my ID. The venue was eerily empty… He gave me my ID back and told me to get the heck out until the place opens, and that the bands didn't go on until 9. So I had some time to kill!

I went to a coffee shop across the street and picked up my time-waster of choice whenever I'm in Dallas: The Dallas Observer. The Observer is the "free press" of Dallas. It's all over the place and it usually has a few stories about Dallas drama (usually in regards to public corruption and whatnot) and reviews of various arts & culture events.

Imagine my surprise when the front cover had absolutely nothing at all to do with Dallas! The cover story last night was about a Denton band, Midlake, and the life and times of the music scene in Denton. That's right, Denton is so awesome it scored a cover-story in a local newspaper based in a completely different city! It was a really good article, and I recommend it to anyone who is interested in the music "scene" in this city of ours.

Disclaimer: I have not yet listened to Midlake! I am recommending this article solely on journalistic merit! I've been meaning to give them a listen, but I got home late last night and woke up early for classes this morning.

After treating myself to a really fine cup of coffee and a really fine article about a really fine city, I returned to the Lounge for my second attempt. It was open this time, and the first thing I saw when I walked in was none other than Matthew Friedburger staffing his own merch table! We had a nice chat about all sorts of things (including the fact that their next album is going to be a silent record).

Later on Matt traded places with Eleanor, and I told her they should've come to Denton—and she agreed! She would have preferred Denton, but their management didn't give them a choice. I can't tell you how pleased I am to live in the city musicians prefer! And it's only going to get better…

I just read an article about one of UNT's latest advancements in the field of super computing. As per usual when I read about super computing, my mind immediately wanders off to a small island off the coast of Costa Rica and I start to imagine commingling frog and dinosaur DNA.

I read Jurassic Park cover-to-cover a lot when I was a kid. Like most kids, I was fascinated by pretty much every portion of the book, but I still remember one specific detail to this day: the Crays. Michael Crichton really dwelled on the Cray X-MP supercomputers that were behind the park's operations, and to this day I still kinda believe that supercomputers are magical machines that can do the impossible.

As it turns out, the Cray X-MP cannot do magic. By today's standards, it can't even keep up with high-tech toys. At its best, the Cray operates at approximately half the processing power of an Xbox--not an Xbox 360 mind you, just a regular Xbox. Needless to say, the magical Crays of that era can't compare to a modern day Pentium Processor.

As it happens, UNT has a super computing cluster of its own for computationally intensive research. The Talon Research High-Performance Computing System is a supercomputing cluster made up of 224 computers. Each one of these computers has a pair of quad-core Pentium processors. Each one of the cores of these processors possesses more computing power than the Cray X-MP could ever dream of. It's pretty awesome.

I was browsing the (actual, physical) message board for the school of Electrical Engineering a couple of weeks ago, and I spotted a flyer for a totally awesome class: Applied Numerical and Probabilistic Methods for Pattern Analysis and Recognition. I'm pretty sure you need at least 3 years of math to decipher that title, so don't be sad if it just looks like gibberish. The fact of the matter is it's a really math-y class that is focused on analyzing the world we live in, so I'm all over it. Here's the flyer:

There's a lot going on in this flyer. Possibly too much. To the untrained eye, the most awesome thing about this class is not immediately apparent. I'll give you a hint: It's in the "Text" section. See it? The textbook for this class is ABSOLUTELY FREE! The whole thing is available for free on Google Books, and that is spectacular.

Everyone can appreciate free books, but it's even easier to appreciate when you've been in school for awhile. Textbooks have to be purchased at the beginning of every semester, usually all at once, and they typically cost an arm and a leg. Any professor that helps lighten that load (price-wise AND weight-wise) is definitely a friend of mine. Google Books' rapidly expanding library will hopefully make this a much more common occurrence in the coming years.

Google Books has a tremendous archive of books available for perusal, but this is the first time I've personally come across a relevant textbook. Previously I've only used Google Books when I really needed to kill some time. (Classic novels are great for passing time while waiting for an oil change or an appointment.)

For some reason, it never occurred to me to search for my textbooks. I wonder if any of my other textbooks have made it to Google Books…

Happy New Year everybody! I hope you all made it through that ARCTIC BLAST safely. I spent most of December in Austin, so I missed out on all of the awesome winter weather we got up here. A "White Christmas" in Texas is a rare thing indeed.

I'm back in town now, and the weather is back to the normal winter range in Texas: 50-60 degrees. This works out really wellfor me, because I'm planning on doing a lot more biking this year. I got a sweet new helmet and bike-lock for Christmas so I now have absolutely no excuse.

My bike is a 21-speed with un-bust-able polycarbonate tires, and it's a great way to get around Denton. Denton is a great city for biking. Everything is nice and close together, and the roads are plenty wide. There are also a handful of parks throughout the city that are great for recreational riding.

My place is 2 miles from both campuses, and less than a mile from just about everything else. The average person on a road bike can maintain a speed of approximately 15 mph. Even if I am really lazy about it, I could bike anywhere in Denton is less than ten minutes, and in weather like this, the drive is practically air conditioned! If I can invent a way to carry my books and groceries on this bike, I'll basically never have to use a car again.

I sometimes wish I had gotten a mountain bike, though. There are a ton of parks and trails around here, and a road bike is no fun in the woods. Maybe when this bike wears out I'll replace it with something that would fare a little better on the greenbelt.