μblog: engineering from the trenches

I have made few attempts to keep this space updated and relevant over the past year, but ultimately failed. I have nearly completed my PhD so I have gotten extremely busy with finishing experiments and writing/editing my thesis. I still do analog and digital design in my day-to-day life, except, most of that work cannot be published here directly. I no longer plan on updating microblog, however, I will leave it up for at least the forthcoming months until the end of the internet in case anyone is interested in saving some information. Thank you readers, it has been a great ride!

Update: I had no idea that there were so many readers, so I will not disappoint and will do my best to keep this content up indefinitely. I may add in the future, but it will not be nearly as frequent as it was in the past.

P.S. I will be looking for an industry job in medical device design in the coming spring, so don’t hesitate to contact me if you are looking for an engineer.

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I have been very busy at the lab lately, too busy to update ublog regularly, and this set of formulas from Gamma Instruments has saved me a bit of trouble. Several air core inductor designs are outlined which allow you to make your own custom inductor, within reason, if you need to test something and you don’t have the part on hand. Typically, the inductance values will be modest, however, it is much easier to make an inductor yourself than a reasonable capacitor. Just think of all of the folding!

( pancakewheel )

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I have been reading James Gleick’s Chaos and I must confess that I am very impressed with the book so far. I am beginning to realize some of the practical applications of non-linear dynamics to analog circuit design, however, more on that later. What has been very interesting is the slow change in the mentality of the scientific world, from the notion that a small change in a systems initial conditions only warrants a small change in the output, to the reality that small changes in initial conditions can generate wildly different results. One of the pioneers in this field was the late Edward Lorenz. He discovered that a slight change (less than 1%) in the initial conditions of his deterministic weather model, which was numerically integrated, would cause the outcome to diverge from the unperturbed simulation to the point that the two weather systems were completely different after several days. The error in his integrator could not account for this disparity, therefore, he went through some analytic computations and found that simple differential equations can have very complex behaviors that were very dependent on initial conditions. He published his results in the Journal of Atmospheric Sciences, a paper that is well worth looking over. For those who are not mathematically inclined, looking over the introduction and conclusion should provide some insight into the paper. Additionally, this is the paper where the often duplicated Lorenz attractor, or butterfly attractor (figure 2) makes its first appearance.

( 1963lorenz-deterministic-nonperiodic-flow )

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It took me a few months to finally read this book, but it was well worth it. I have been reading it prior to sleep as it was so full of information that it was difficult to read more than ten pages without taking a break to think about all of the new ideas. Furthermore, the information was presented in such an accessible manner that even those who are not specialists in relativity, topology or physics can appreciate the message.

I selected this book because I figured the topic was far away from electrical engineering that it could give a new perspective on understanding what is implied by measuring time and distance. Sure enough, this book provided many insights into the nature of our universe through the relation of time and space measurement. I will avoid summarizing the book, however, I will mention that it would be a pleasant read for those interested in non-Eucledian coordinates and the effects of gravitational fields. The book is extremely well written and reads much like a lecture series where the audience does not need to be able to carry out all of the steps of each operation, but acquires a taste for the process and a deeper appreceation. From the point of view of technical written English, this was one of the most understandable books on a physical subject that I have read in some time.

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I have many AS and LS series logic gates lying around, so I figured that I would image some as they would be more instructive than looking at the latest CPUs coming out of Intel. I have a few more lined up so please comment if you want me to follow this reasoning. Today’s subject is a hex-inverter, the 74AS04. Below are images of the whole chip and a blowup of the top-right inverter gate.

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Now that I have everything unpacked, the IC Friday program can resume. Today’s a nSpire processor sent in by Travis Goodspeed. Two notes of interest are the prominent LSI LOGIC badging and the dual CHIPIDEA cores. The model number looks like CI12320, but that is not listed on their page.

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I am moving across town in two days and have a grant application deadline so there will be no IC Friday this week or next week. Below are a few pictures of the disaster area that is our apartment.

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Looks like EMA is looking for beta testers starting next month. Everyone accepted gets early access to the new Orcad/Cadence tools and the t-shirt above. The most comprehensive reviewrs are said to be entered in a raffle for a flat screen monitor. Try your luck.

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Today’s IC Friday is another reader-submitted chip. This is cryptoworks six-pin smartcard. The only writing on it is “TUBEAV A”.

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Today’s entry is an old memory chip from Mitsubishi, the M5K4164. This is another chip submitted by a reader, again, all the way from Iceland.

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