repak shawahb
armed and hammered

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rsw@jfet.org


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Mon, 30 Jan 2006

jetblue

...is great. I flew roundtrip Austin-Boston over a weekend for under $170, and since they were nonstop flights, I was able to leave early Monday morning and get back to Austin in time for work. How hot is that?

To those I missed this time around: fear not, I'll be back.

To those whom I saw: be afraid, I'll be back.


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Wed, 25 Jan 2006

do not taunt the metal rev

Tonight (well, this morning, whatever) I stayed at work until about 1a heroically (yeah... my ass) fighting to PG (= "Polygon Generation" = tapeout) a metal rev of the Quad so we can get it to the fab before the start of the Chinese New Year (if it gets in before, it gets processed through the holiday, otherwise it doesn't start until afterwarfds—ugh). I am basically the owner of this whole thing; Ion made the couple little schematic changes, then handed it over to me for layout, and now I'm doing all the PG verifications. I guess it's good practice for when I'm leading a chip.

I took the opportunity while waiting for the LVS, DRC, etc to run (fuckin' DRC takes almost two hours on a dual Xeon with 4 gigs of RAM) to finish designing the ESD pads, so now it's just a matter of getting them to fit into the pad ring, doing some sim-yoo-lation, and getting them consecrated by Marius, High Priest of HBM.


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Mon, 23 Jan 2006

a new soul arrives

...the title I wanted and couldn't quite have a few days ago. Hooray Soul Calibur.

I've been meaning to add Cyrus to my blogroll for a while now, and have continually forgotten to do so. So now he's added, and everyone knows I'm lame. We cool?


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burning discharge

Not that kind, sicko.

I've just been tasked with the ESD clamps for a high-voltage (200V) telco line interface chip (SOI, baby). It has been handed down from on high that they shall be finished this week, since tape-out looms close on the horizon. I'm pretty pumped to be working on them, and I see plenty of opportunities for area-saving cuteness already.

...after all, everyone knows I'm all about cute.

For the record, transistors in high-voltage processes look funny. They're hexagonal! (You know, like the IRF "HEXFET" thing).


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quux nexxus

FYI, quux.ws is now officially pronounced kwuks-us.


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Sun, 22 Jan 2006

an oldie but a goodie

God I love the internets.


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Out of my way! I WILL RUIN THIS PLAY WITH MY ANGER!!!!!

Troy Polamalu is an unstoppable juggernaut. I have decided I will grace his jersey with my torso come Superbowl Sunday.

Also, more info on the Flutie drop-kick—video of it happening, and an interesting article about Flutie from 1998. Also, see Wikipedia's entry on the drop kick.


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Sat, 21 Jan 2006

denouement

The cases are done. Feast your eyes.


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Thu, 19 Jan 2006

a new career path arrives

Just in case I get demoted from design, I can always become a layout mercenary. I had to do some emergency metal revisions for a chip we're sending out next week, and I ended up scavenging a few dummy transistors into a couple usable circuits. It's always fun to take a random assortment of transistors, some of whose terminals are connected to points in the circuit from which they can't be disconnected, and turn them into a useful functional block.


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Wed, 18 Jan 2006

talkee talkee

Wow, lots of entries today.

After work and a quick dinner (after which Mike managed to spill a soda all over the front seat of my car) a bunch of us headed over to Tim's to watch Underworld—in preparation, of course, for the release of the sequel this Friday.

I couldn't sleep when I got home, so I went ahead and made the magnetic shields for the CRT clocks. It seemed like one layer of 6 mil AD-MU-80 (80 Ni/20 Fe) would have been enough, but I went ahead and did two on each just to be certain. Success! I suspected given the magnitude of the distortions I was seeing that the field strength wasn't too great, and it appears that I was right.

Now what to do with the 14x60 sheets of 4 mil AD-MU-80 and AD-MU-00 and the remaining 4x36x6 mil... what else needs some shielding?


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maybe it's just the ozone talking...

...but I strongly prefer the nitrogen peroxide that the tweeter is feeding me. I think Marduk still prefers Stimutax, though.

Someone ought to give me a helium environment for Christmas so I don't kill myself or something. From an article on tweeter technology by NewForm Research:

Think of it as an arc welder driven by an audio signal. No moving parts, therefore no resonances. As fast as the air itself. And now the fatal flaw. The developers left the driver on overnight and returned the next morning to find everything in the room white from the ozone produced by the process. If this tweeter had proved otherwise practical in the early 60's, we would probably all be dead of skin cancer by now.


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random thought before I go to sleep

What if we weren't engineers? We wouldn't be able to dream up stuff and just make it.

Mmmm... I love making. And dreaming.

'nite.


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from the frontline

It's 1a and I'm still at work.

To be sure, I haven't been working for the last several hours—I was just using the wondrous laboratory facilities here to build up the new audio modulator for my plasma tweeter.

Success! After adding an LC pi network between the emitter of the output follower and the plasma modulator, the audio section worked perfectly. Good thing we have an assload of high voltage caps and high current inductors around this place—I needed 'em.

Even with the filter, when the plasma is running the E fields coming off the stub are strong enough to induce 5Vpp ripple on the 300V supply—which is bypassed with no less than 680 microFarads of bulk capacitance! Admittedly, I do need to add a liberal sprinkling of lower-valued caps whose impedances actually look capacitive above, say, 10 kiloHertz...

By the way, do the math on that shit... those caps are storing a lot of energy! Those of you who were around at the time probably remember when I literally VAPORIZED a resistor—leads and all—on the very power supply from which this whole thing runs.

...oh yaah, and measurements indicate that when the flame is about half an inch high, I'm burning about 180 Watts into the 22 MHz carrier. Fuck yeah RF burns, baby.


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Mon, 16 Jan 2006

on the epistemology of humor (excerpt)

It's a work I'm planning for later this year, but for now you get this glimpse:

Humor in its most basic form draws from one or more of five areas, which I will call the Five Pillars of Humor. These are,
  • Xenophobia—Is it different? Then it's funny. This includes homophobia, racism, sexism, and religious humor.
  • Violence—pain is good for the soul. Also, it's good for a laugh.
  • Irony—it may seem like a compliment... until your sarcasm melts their flesh off. (...and that was funny because it was violent.)
  • the Ridiculous—the one category that truly does not require humor at someone else's expense, the ridiculous is humor nevertheless. Puns and Chuck Norris's cancer-curing-too-bad-they-don't-exist tears go here.
  • Poop—in the words of Lord Opticord, "dog poop! ahhh hahahahahahaha, dog poop! That's a good one!"

Regular readers will note that this is a substantial revision of my earlier work on the five pillars. I feel that broadening its scope from the previous instantiation makes this a theory which appeals more to the masses, thus driving up book sales.

Also, before anyone else says it, "yay, a non-technical blog entry!"


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gorgeous models for whatever you want

I found a stash of spice models. Man, that's just hot.

Also, reading this makes me sad. I always thought that the audio hobbyist community was at least a little competent, but these guys understand almost nothing about circuits. It's kind of painful, and a little disappointing. I will continue to choose to believe that amateur radio hobbyists are more knowledgeable than these guys—admittedly, given that there's even more voodoo up in the closer-to-daylight reaches of the spectrum, if I were a betting man I might have to reconsider my position before setting any odds. (In case you're wondering, I ran across that page searching for a spice model for the MPSA42 transistor.)


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Sun, 15 Jan 2006

a thought experiment

Every once in a while, one ought to derive the complete transfer function for some relatively nasty circuit by hand—just to, you know, stay in shape. Simulation is an evil crutch.

In that vein, I decided to redesign the audio modulator for my plasma tweeter and make it a bit higher performance (the last one was embarassingly simplistic and st00pid). To make it more fun, I decided to make it closed-loop but ac-coupled, and I wanted to use a minor loop for the DC biasing.

Thus, the circuit you see to the right, which is perfectly serviceable as a gain-of-100(ish) audio amplifier with independently variable DC output voltage (via the pot in the loop). This'll let me run the screen bias where it wants to be for the appropriate plasma flame size, and simultaneously give me decent audio fidelity.

Note the DC loop right around the op-amp to bias the common-emitter stage and the inverting feedback (to the wrong terminal on account of the inversion in the external circuitry) that handles the AC loop.

Yay.


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Thu, 12 Jan 2006

...but I only have eyes for μ

After a minor circuit redesign (resulting in the savings of two high-voltage caps) achieved with the old boards by way of some trace-cutting, my first scope clock now has a friend. Like George says, you just need two of some things, like helicopters.

The next thing I had to start thinking about was how to magnetically shield the clocks when I put them in their cases. Since space will be tight, the CRT will be sitting basically right on top of the power transformer, which rudely spits off this rather large 60Hz field that causes the picture to swim (very!) noticeably. Since my refresh rate is not quite at 60Hz, the swimming ends up happening at the beat frequency between the mains 60Hz and the draw rate from the PIC. If the two are synchronized—something I've played with in code—you don't get swimming, but you do get static distortion. Plus, I can't quite get the refresh rate up to 60Hz with the code as it is right now, and while I can probably hit 55Hz, I'd have to draw fewer points in order to squeeze out that last bit of performance. I'd rather just shield the bastards and not worry about synchronizing the refresh.

After some research on what's available, I've decided to turn to Advance Magnetics, purveyors of a few different kinds of flexible high-permeability materials with which I"ll wrap the neck of the CRT. There is something very suspenders-UNIX-jiggaHertz cool about talking to the guys who work at a company like that—I mean, how often do you call up a company and start talking physics with the person who answers the phone? But don't take it from me—have a look at their engineering catalog. OMGHAWT.


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Wed, 11 Jan 2006

scientific progress goes boink

...but only after much fizzling, popping, etc. I cooked a good half-dozen transistors and several high-voltage caps getting this sonofabitch working (mostly because I was being an idiot with respect to the return current paths), but that's to be expected—after all, any time I build a power supply, some magic smoke earns its freedom.

The results speak for themselves, and yes, the time displayed on the clock is correct.


The whole enchilada.


Old and busted? Blue hotness.


Let me count the hacks.


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Tue, 10 Jan 2006

productivinsanitillness

RCA

Also, clock construction is progressing nicely. The board is assembled except for the deflection amps (didn't have the 430k resistors; I'll have to borrow some from work), and I actually fired up the CRT and got a hot little blue-white dot. A tweak or two on the focus and control grids and it was dialled in nicely. Since the trafo is rated for 480 VRMS center-tapped (240-0-240) at 40 mA and I'm only drawing about 3 mA from it, I'll have to add a series resistor on the primary or risk blowing up the power supply caps (they've got about 390 V across them right now, whereas they're only rated for 350 V—by the way, the United Chemi-con KXG line of electrolytic caps gives exceptionally high charge storage density; I highly recommend them for your next high-voltage project).

Pictures forthcoming, and enclosure on its way.


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will of the overmind

Submit.


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Mon, 09 Jan 2006

step aside, James Brown

Get up, get down, get dressed.

I couldn't find the logo in high enough resolution, so I just drew my own. The corners of the square overlap the diamond more than they should. Such is life.

I think I'm going for bright green. Ladies, don't be shy—we all know that pink is the new black.

Edit: not satisfied with just one, I also had to do a General Radio one. That's a hot little logo. Next up is probably the old-school RCA (with the lightning bolt coming off the bottom of the A).


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Sat, 07 Jan 2006

can't stop the funk

I can't claim credit for the title—Woz suggested it when I failed to come up with anything. I guess I'm in an unstoppable funk of my own.

Wow. That's completely hot, and art.com actually sells them.

Also at Woz's suggestion, I'm going to make a bunch of t-shrets out of the logos of various old-school engineering firms. I'm thinking Telefunken, RCA, Burroughs, Weston, General Radio, stuff like that. Respond with other ideas—you know you have a favorite or two I'm forgetting.

Oh, also, feast your eyes upon my latest clock project. The boards were delivered via FedEx on Friday, so next week I'll be assembling, testing, and tuning.


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Fri, 06 Jan 2006

leavin' on a jet plane

...bound for Vegas. Today I head out for a weekend of CES, Cirque, and general schwag whoring with Ms. Wozniak. I'm psyched as all shit.


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Thu, 05 Jan 2006

coming up roses

Last night Tim, Mike, and I joined many others in watching UT play USC in the Rose Bowl at Dylan's (on his breathtakingly gorgeous Runco 3-chip DLP projector). Despite the best efforts of USC, the announcers, the fans, and even some of their own players (witness the many fumbles), UT came out on top in what turned out to be a game every bit as great as we'd expected. You heard it here first: Vince Young is some sort of cybernetic alien being from a planet where football isn't just a game, it's the only viable means of survival (as well as the mating call, although I'd imagine it functions well that way here on earth too, at least for Mr. Young).

This morning at the gym, I met a very interesting person, Seton Motley, a rock musician-cum-conservative political columnist here in Austin. I spotted him on the bench, and we got to talking about music—his knowledge of Cornell, Vedder, Gozzard, and their ilk was first-rate, and from talking to him I'd guess he is himself a reasonably good musician as well. He recommended to me, and so I shall recommend to you, Soulhat, a band from Austin whose song Bonecrusher I've just realized I have heard on the radio (and even enjoyed). I'll have to check them out further.

After going from Axl Rose to Dave Brubeck by way of Robert Plant, we moved on to politics, local, national, and international. Being somewhere rather far to the left socially, he and I needless to say didn't see eye-to-eye on several issues, but the conversation was at the very least entertaining. At the end of it (after the passage of no small amount of time!), he mentioned his website, NewsOfTheDay.org.

Interesting people are cool.

Sonofabitch my 5-day simulation just died because some incompetent jackass in IT decided to kill the license server. I'm going to make a quick stop by his office on my way to what I can only assume is prison given how angry I've just become.


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Mon, 02 Jan 2006

<title goes here>

Well, I'm disappointed that my last attempt at finding a USB-serial converter that'll work with my PIC programmer has failed miserably. Now I have to send the sumbitch back—but at least I get the shipping back, since UPS screwed up.

If you were waiting with bated breath for a link to the Imogen Heap album, wait no more.

Also check out So Young But So Cold, a collection of underground French music from 1977-1983. This is what the French were doing while we were punking out, apparently. Whatever else you can say about it, you have to admit it's damn good stuff. Enjoy.


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Sun, 01 Jan 2006

backbreaking criticism

I'm not clever enough to keep my titles entertaining. Shoot me. With a .30-30.

I went with Cindy and Casey to see Brokeback Mountain. I didn't have any particular expectations, except that it would be something of an Oscar-chaser. Turns out, I was wrong to expect that—it was a genuinely well-done film and a very good story. It's one of those movies you should probably see so you can talk about it at cocktail parties or on dates, or if you genuinely like somewhat depressing unrequited love stories. If I were you, I'd wait for DVD.


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