Posts by Chairman of the Bored 951 publicly visible posts • joined 19 Apr 2017
AC, good question. Three answers-
1) You're right in that a reversed cap on a negative rail is probably an error in the schematic. It's very easy to put all your big decoupling caps in a row, beautifully aligned with the positive bar at the top and curved negative side pointed down. Then you slap a bunch of GND at the bottom and slap in the power net labels at the top... Forgetting that one is negative and needs to have the cap flipped. Sails through review because everyone focuses on the "hard" sections and it just looks right.
2) The pick n place robot is responding to a centroid file that specifies reference designator, side, x/y coordinates, and rotation. If your parts library has inconsistencies in, say, whether pin 1 of a diode is anode or cathode - fail. Early 90s tooling had little or no ability to automate management and review of parts libraries
3) In the early 90s pick and place was a two stage process. Very light components were more or less put in place by a high speed chip shooter. Gantry head stays still while the board is (violently) moved underneath. Big components like the electrolytics are too large to place this way because they'd go flying. So the precision moving head 2nd stage would be used... But computer vision didn't work well back then so there was a lot of man-in-the-loop for precision placement and a tech will follow an incorrect silk every time. Crude machine vision wasn't really great at tall components...
I've been doing board design and layout for more than two decades. And if there is anything I am guaranteed to screw up on revision A through about C... It's something on the silk layer. Either a reference designator ends up close to the wrong component or a polarity gets switched. Usually a diode, though, not a cap.
This almost seems like a physical law... Regardless of the effort you put into automation and review... The silk will have an error. Guaranteed.
I tend to put a file named -i in directories a script might find interesting. Forces rm -rf back to interactive mode. Not foolproof of course but slightly better than nothing.
Did rm -rf / opt once, nearly got fired, and not have a tingly feeling down my spine whenever I put any arguments after rm...
I've worked for companies that allowed engineers to spend up to 10pct of their time on personal or team "passion" projects outside of the normal product churn. This is great for morale and quite a few products have come out of this.
If we would allow our software developers to work Open Source efforts using the same model, I think we'd have some progress + skin in the game
I got popped in this one and reported the issue to my company's security officer, per procedure.
She looked at the documents and said, "Damn! They got everything but your sperm count"
One week later, I got the notice from Change Healthcare that all my medical records are up for grabs.
So, yeah, I guess someone DID get my sperm count after all...
I have no use for the "AI" stuff. But I'm a huge fan of the Sony sensor. Fast, high resolution, reasonably low noise, and surprisingly uniform across the array. Slap that behind a decent C-mount lens and even a modest rPi 3 becomes a respectable digital camera. Slap it on a small reflector telescope and it breathes new life into that machine. Remove the IR filter, then point it skyward for more fun.
Fixed focus is not a problem when it's pointed at a bird feeder precisely 2m away :) Ive gotten some outstanding shots, and my kids have named all their favorite birds. Every my daughter away at college will occasionally SSH I to the pi cam to check up on "her" birds. Fun habit.
I keep seeing articles state that 28nm and larger nodes are "legacy" technologies only fit for low tech applications such as household equipment and cheap tat
As a hardware engineer who survived the supply chain crashes of the last several years, I can assure you that 28+NM is absolutely crucial for all technology. Your orgasmotron 2000 microprocessor at <10nm doesn't perform well without glue logic, power conversion, comms, mixed signal ICs, etc.
The west writes off large process nodes as 'unworthy of investment ' at its absolute peril.
Iny experience engineers working remotely expect technicians and engineers onsite to drop everything and be their eyes and hands in the lab. Then we get to play "telephone" over Teams and whatnot to pass information back and forth.
This absolutely kills productivity and morale for those actually at work
If you work for a small firm on the left side of the pond you typically have no choice which insurance provider to use. About the best you can do is choose the level of service or forgo coverage entirely.
Some employers will recompete contracts every few years, most are on autopilot and go down the path of total vendor lock-in.
So I suppose the marketing effort is expended on selling to the businesses - not consumers. The attitude I've seen from the businesses to this sort of third party contractor breach is "stuff happens, nothing you can do - thank goodness it wasn't our IT that got hit. Carry on." As opposed to "I need to find a better contractor"
Joys of employer-provided cover.
The elephant in the room here is that many companies across the world used Altera. Then Intel bought Altera... COVID happened... And you couldn't buy them at any price. Still can't.
Intel apparently never reserved the fab capacity to fulfill their existing part commitments. Those of us who spent millions on IP wrapped around the MAX V, MAX 10 FPGA were and remain screwed. About 12 to 18 months ago, while we were all redesigning our kit to use Xilinx in place of the Intel parts... We were waiting for word from Intel that MAX and Arria were going back into fab. But instead what we got was bumf about "AI FPGA". WTF? Useful as an air horn on a chicken.
Altera is (re)starting out behind the curve. Engineers and companies worldwide are still irritated at getting absolutely screwed. And having just spent loads of NRE on tooling, training, setting up supply chain, new board spins, etc moving to Xilinx there is no way in hell one can justify doing this again to go back to Altera when it has no vision or direction other than AI bullshit.
It will be a cold day in hell before I spec and buy an Intel/Altera FPGA. And I'm not alone.
When the North Anna nuclear power plant was constructed in Virginia, the decision was taken to dam the North Anna River to build a massive artificial lake to serve as the ultimate heat sink. The dam proper can generate hydropower, at least enough to serve as the emergency backup supply for the plant.
This created an outstanding wildlife habitat, reduced the visual signature of the site, and created a beautiful set of lakefront communities and recreational areas.
Granted that trick won't work everywhere, but it is a truly lovely solution where it can be implemented
I lived in central Virginia for a number of years and marvelled at the explosive growth of bit barns in the northern region of the state. The sheer scale of the infrastructure build out is breathtaking.
There is a rather sharp division between the Internet and professional economy to the north and the legacy, largely agricultural economy immediately to the south. There are some pretty serious - and growing - social tensions between these regions of Virginia.
For years Dominion Power has tried to build major transmission lines to better leverage their cheap nuclear and coal plants outside northern Virginia to service new loads in the north, and the local opposition has been strident to say the least. This is beyond your normal "not in my back yard" issue. This becomes personal. The split between Trumpian and Traditional America is definitely on display in that state.
My brother worked for an audio company that sold the radio comms infrastructure to McD "restaurants". Analog (narrowband FM) using only bog standard CTCSS tones to control squelch. No voice scrambling. Customers would call up desperate for a solution when the following sort of thing happened at the drive through kiosks-
16-year old: "Welcome to McDonald's, can I take your order?"
Customer: "Yeah, I'd like a whopper meal with a coke big enough to swim in"
Interloper: "For fuck's sake, man, you're what? 300 pounds? How is eating this s...t gonna help THAT?"
Customer: "What the fuck?"
16-year-old: "I'm hearing voices!"
Interloper: "Yes you are! Stop smoking weed, dumbass!"
I miss the 90's. Simpler times.
I used to work for the USN...
We saw the Blanket Purchase Agreement process as a much needed tool to avoid some of the more ridiculous issues with government acquisition. One cannot obtain flexibility without incurring risk.
OF COURSE the Navy had to f___ this up at the billion-plus dollar level. This is why we cannot have good things.
Tee up another six or so hours of mandatory training for all USN civilian personnel - whether they have anything to do with acquisitions or not. Tee up a vast new purchasing bureaucracy to reform BPA literally to death.
Watch every swinging dick involved in this take a VP position at Microsoft.
Popcorn time.
Back when I worked for good old Uncle Sam, my team would write numerous formal technical reports. The review process was interminable, it seemed there were more signatures required for TR release than needed for the missive we sent King George in 1776.
This raised an important question- were any of these esteemed leaders actually reviewing anything?
We decided to use stack (read) canaries - if the reviewers called us on the carpet when they found something outrageous, we knew 1) they might just be functionally literate, and 2) they actually read the paper
After all, we would back out all the substitutions when we were done, right? Except for that one time we forgot.
That's when the lab sponsoring our work learned that instead of my real title I'm the Director of Secret Police. The Applied Physics Lab became the Applied Political Lab. The table of acronyms spelled out the meaning of FUBAR. SAPFU, FOAD. Apparently one of our investigators has the improbable name of Will E. Wanker...
Another aspect of this is a temptation to gold plate the name of any capability or system. I observed this constantly when I worked for the US Navy.
Example- we needed to perform some modeling and simulation of antenna systems. The appropriate tool was a nice SGI Power Origin cluster. A lovely piece of kit, but nevertheless just two racks of compute capability.
One day I arrived at work to discover a sign on the door calling the system a Supercomputer. The BOFH was now a Supercomputer Center Director. And so on.
I wonder how many of those "data centers" are rooms of excess PCs gathering dust. After all, when it's time for annual reviews would you rather be the Deputy Vice Assistant Obsolete Hardware Wanker, or Datacenter Director?
I should have named myself the High Priest of Computational Electromagnetics. After all, I had the Director of Supercomputing working for me.
I lived the Navy IT dream for many years. When we decided to go with outsourced IT through the Navy/Marine Corps Internet (NMCI) it was - and remains - an absolute cluster fsck. The USAF looked at NMCI and wisely said, "EDS will own all our stuff? Er, no. We will let Navy stuff it." The Marines "My Ass Rides In Navy Equipment" ditched it
Then we doubled down and added SAP ERP to the cesspool.
Through it all the Air Force still had relatively functional IT. Now, apparently, they get to embrace the suck
Upvote for an excellent post! You're quite right that frontend saturation is the main RF concern here.
A relatively cheap surface- or bulk- acoustic wave filter can do the filtering job but would add a fair amount of insertion loss - several dB - and that directly reduces the signal/noise ratio of a receiver. These would cost from single digit dollars to a few tens of dollars each. The systems engineering question becomes whether one is willing to accept the loss of SNR.
A cavity, ceramic resonator, or printed circuit "stripline" filter would work nicely. I did some back-of-envelope calcs that suggest a relatively low complexity design would provide >52dB of rejection over the 5G lower band (*). Cavities tend to cost around $100+ in bulk, ceramics probably $20-$50, integrated stripline varies depending on how much one would have to modify their existing PCB design to accommodate.
Another approach is to use low noise amplifiers on the frontend that have high dynamic range. Marginal cost for such an upgrade is minor, but this involves spinning new PCBs - effectively a new product.
So here is the real problem: radalt are safety critical. If I add a filter, mod a PCB, look at it funny, or even think dirty thoughts in it's vicinity... The FAA regs will require a recertification. Thats extremely expensive. Is have to draft maintenance instructions for all the radalt in the field, and these would need to be reviewed. The radalts FCC certs, CE certs, MIL-STD-461 EMI testing, MIL-STD-810 shake n bake testing, etc would have to be re-done. Somebody has to pay for the labor to installl, inspect the installation, certify it's done to spec... None of that is cheap.
What's going on here is an effort to get someone else to pay for the systems engineering to figure out if there even is an issue, and be on the hook for any mitigation if there is. Lastly, people want a paper trail so that there is someone else to chuck under the bus if an airliner ever has an issue.
(*) Butterworth, fifth order, would work nicely.
Had a manager with a PhD in some irrelevant humanities field ... barely managing a technical team, all of whom had at least a BS degree in hard sciences.
In any technical discussion she didn't understand, she would say, "Well IVE got a PHD!"
Best response? "No shit! Where did you get it? ...long pause... Do they give refunds?"
During a branch meeting we were asked to congratulate The Chosen One on their stellar accomplishment- bullshitting their way to an MBA.
Retiring curmudgeon says, "Very good! You're now a sexual intellectual!". Collective gasp, because that was over the line, even by early 2000's standards.
Somewhat says, "What??"
Curmudgeon:. "He's now a fscking know-it-all!'
I'm referring to Fermilab'a MiniBooNE experiment. An old colleague worked on some of the high speed electronics for the PMTs-
https://www.fnal.gov/pub/science/experiments/intensity/miniboone.html
The microboone follow-on experiment is also extremely interesting.
An enlightened boss!
I've got a great one right now. His attitude is that holidays and weekends are purely for rest and recreation. While some long days are inevitable, when they happen the program managers get their asses chewed out for improper resource management.
Question-
X-ray and acoustic microscope systems are routinely used for QA of printed circuit assemblies, particularly for dense IC packages such as BGA. They are also quite useful for counterfeit detection on ICs. But so far as I know you learn nothing of the state of running electronics
Now an IR imager can be useful in this role...
I was asked for some career advice, "Should I take a deputy director role in division X?"
My snarky replay was along the lines of, "Why the hell would you do that? It's run by a fucked up, half-witted bootlick with a nose for blow!"
I didn't know that they guy was the stepson of the company president. Blowback was surprisingly light, because I think the president's wife was pressuring him to "find a job for little Timmy" and Timmy ended up getting promoted into harms way, in accordance with the Peter principle.
The BOFH solution would be to co-locate segments of detonating cord along your fiber path. Combined with some electronic safe/arm devices, slappers, and an occasional booster + main charge to keep things exciting you can defend your cable.
"If I can't have a cable, you can't have that 'effen backhoe blade!!"
Bonus - after a few shots it's unlikely you will have idiots trying to tap the cable, too.
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