What does "higher-order math" mean? For some, it's algebra.
For a lot of radar theory, knowing linear-systems theory (and thus Fourier transforms) suffices, although modulation theory involves Bessel Functions (which are defined in terms of infinite series).
I did meet an EE who had never heard of harmonics. I have no idea how they graduated.
Joe Gwinn
Actually during one of my consulting projects in the mid-90's I reversed that trend at a client. They had a big DSP do lots of Fourier transforms and the auto-calibration routine for that board took forever. Tens of seconds. I reverted all that to time-domain and it was finished after a few hundred msec, every single time.
In the 80's we often did it with zero-crossers. Less math but blazingly fast.
Assembler is the manly way of programming :-)
The other Waterloo are terminations. At one place they had used Thevenin terminators just about everywhere. The result was that the system needed a whopping 5V/100A power supply and a lot of heat came out of it. I redesigned some stuff and I am a strong believer in AC termination. One day ... beeep ... click ... beep ... click. The switch mode power supply would not start. Call to the manufacturer. Turns out, now we had landed below the minimum load for that power supply. Which hadn't been documented anywhere ...
[...]
Uh, pop mail has been obsolete for like 20 years now. Not sure what the hell you're doing wrong, other than everything.
Nah - only machine code. But it makes your hair turn gray and fall out.
Heh. So it got a nice warm load resistor? To prevent condensation, you know ...
Joe Gwinn
What was this big DSP doing? This story rings a bell.
In radar, the initial calibration involves multiple alternating conversions between time and frequency domains, because the desired result is a clean pulse in the time domain, achieved by adjusting phase and amplitude settings as a function of frequency.
Once the correct settings have been found iteratively, subsequent calibration is by adjusting the various settings back to those golden numbers - the file containing those golden numbers is of course called a golden database.
Antenna pattern is first calibrated by a like process.
Joe Gwinn
Fourier transforms, impulse response, correlation, filtering, and phase shift concepts are a 2nd or 3rd year undergrad EE class, "Signals and Systems." That's basic stuff, not higher-level math.
But phase shift measurements seldom use a Fourier transform.
Is ring theory useful in electronic design? Sounds unlikely.
AC termination is nasty for DC-asymmetric data. Fine for clocks or biphase or 8B10B sorts of things.
Of course if he had skipped vaccination and gone directly to getting Covid-19 he'd have had a better chance at worse blood clots.
The Moderna and Pfizer vaccines exploit mRNA technology to get your body to make a version of the Coviud-19 spike protein. That can have side effects, but the cost-benefit analysis makes it pretty clear that it's wise to run the risk. The problem there was Covid-19, not mRNA technology. I got the Astra-Zeneca vaccine which used a tweaked adenovirus to make my body make the same version of the Covid-19 spike protein. Blood clots are a low frequency side effect of that technology too.
I agree. As a young teenage hobbyist with little guidance, I went through about four years of frustration at not being able to design my own circuits. I'd salvaged all these tubes and things from a couple of old TVs that my folks were chucking out, but didn't really know how they worked. (Transistors were too expensive, and IC prices were just moving down from the stratosphere.)
That bottled-up frustration gave me a fire in the belly to figure it all out, which eventually I mostly did. (Never got round to using anything from that Motorola MNOS nonvolatile memory book they sent me, though.)
At IBM, I was occasionally asked to interview candidates, and one of the things I always asked them was whether they had any hobby background in electronics or physical science. Almost all the best designers I know started out as hobbyists, which ISTM says more about the fire in the belly than the expertise so acquired.
Now if you'd just get off your duff and write that "Electronics From Scratch" book you used to talk about, we might have a few more. :)
I dunno. Washing out of a hard program isn't the worst thing that can happen to a young person. It's not nearly as bad as hanging on by the skin of your teeth and then failing over a decade or so in the industry.
The old saying, "C's get degrees" has caused a lot of misery of that sort.
Gin and tonic for us recovering Commonwealth types, thanks. Lately I've been enjoying Inverroche Verdant from South Africa, with lots of ice and a splash of Fever Tree tonic. Highly recommended.
Cheers
Phil Hobbs
That's nonsense . Instincts are acquired, they are innate.
"stereotyped, apparently unlearned, genetically determined behaviour pattern."
John Larkin has any number of strange ideas on how university education works. The probably reflects the fact that it didn't work for him.
It usually is, particularly at rubbish universities that don't attract gifted kids.
The Australian university drop out rate in the 1960's was about 40%. 30% of students got through in minimum time. The remaning 40% repeated a year or switched courses. A high prestige course like medicine did better. At Melbourne they took in 200 students a a year (out of 800 applicants). 95 of the first 100 would graduate, and about 60 of the second 100.
Bizarre.
<snipped nonsense>
Define "higher level". There are enough subtleties in going from 1-D to
2-D Fourier transforms alone to fill up a graduate course pretty well. (You could fruitfully spend a quarter just on 2-D phase unwrapping--a very deep and surprisingly pretty topic that is also super applicable in instrument-building.)Beyond PDEs, calculus of complex variables, asymptotic methods, and numerical analysis, I learned most of the "higher math" that I know in physics courses.
Cheers
Phil Hobbs
I've been giving a few trial lectures. Leprechauns dressed like elves hurling electrons between big bonze statues, things like that.
Our sensors are differently calibrated.
On a sunny day (Mon, 2 Jan 2023 22:03:45 -0000 (UTC)) it happened Cydrome Leader snipped-for-privacy@MUNGEpanix.com wrote in <tovkc1$sj3$ snipped-for-privacy@reader2.panix.com>:
Well using it every day since 1998. Have a nice directory with ALL emails since that day. Easy to search for keywords with 'grep'. Checking mail with fetchmail takes a second.. Most is scripted, Pine as email reader, On my laptop, or any Pi I have..
And reasonable secure (never a problem since 1998).
Backups with one command (script).
If you count the number of productive hours lost by clicking around in microsore shit then at some hourly rate you have saved maybe zillions... using fetchmail. Not even counting the update downloads, energy used, frustration and no way to find anything back to 1998 in a flash. DO YOU NOT SEE YOU ARE BING SUCKED BY microsore and others?
On a sunny day (Mon, 2 Jan 2023 12:20:22 -0800 (PST)) it happened whit3rd snipped-for-privacy@gmail.com wrote in snipped-for-privacy@googlegroups.com:
Any old AM radio is basically a spectrum analyzer. Fourier, harmonics is the first thing that a radio tinkerer encounters. Waveforms, filters, sines, all comes naturally, With code Fourier in asm is fun too:
On a sunny day (Mon, 02 Jan 2023 17:40:24 -0800) it happened John Larkin snipped-for-privacy@highlandSNIPMEtechnology.com wrote in snipped-for-privacy@4ax.com:
Indeed, like analog video 1 Vpp You lose your black level... OTOH a diode after the RC will fix that for video (clamp the negative sync pulse at some fixed level). It all depends...
I have had good mileage out of linear systems, anti-aliasing, Padé approximations and calculus of variations over the years.
Other obscure functions like prolate spheroidal wavefunctions have been handy too. They are another family of functions that are their own Fourier transform when band limited (truncated) in one domain.
exp(-ax^2)sinc(bx)
Depends what you are doing. Ultimate dynamic range was our requirement.
Just about all of of MRI body scan imaging and radio astronomy is wall to wall big Fourier transforms (and some quite tricky interpolation of raw data onto a rectangular grid for good measure).
From 48 years ago, vidicon cameras for factory surveillance , car headlights would wash out the picture. One of the guys made a circuit that that clamped any high level white (headlights) to zero (black). Worked great, the cars just had two black blobs on the front, and the picture didn't wash out. Mikek
On a sunny day (Tue, 3 Jan 2023 04:52:58 -0800 (PST)) it happened Lamont Cranston snipped-for-privacy@gmail.com wrote in snipped-for-privacy@googlegroups.com:
Ha, vidicon cameras, designed and build one in 1968, got me a job at the national TV network.
Vidicon cameras were for example used in film editing tables.
We had all sorts of stuff, Orthicon, plumbicons (in the color cameras) ...
Things sure changed with the first silly-con sensors.....
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