Error correction in short packet.

Underspecified problems do encourage lots of lateral/goofy thinking.

Of course, some people are hostile to ideas. Their career path is more McDonalds than electronic design.

Goofy ideas aren't really welcome if they upset a sizable fraction of effort already invested. Ideas are cheap. Realizing them is costly. You'll want to be selective.

Jeroen Belleman

Economists call that the Sunk Cost Fallacy.

Ideas are cheap. Realizing them is costly.

Sometimes an idea can wipe out a million dollar investment but have a shorter path to done. Managers don't like that situation.

Good ones will laugh and take the short cut (after checking it carefully, of course). They'll also listen more carefully to the person that came up with it. ;)

Since the budget will already have been approved, they might continue along both paths for a bit, to build confidence in the new approach before committing fully to it.

Cheers

Phil Hobbs

Everything is easy for those who don't have to do the work themselves. I certainly include economists in that lot. The sunk costs are needed to get intimate with the problem to be solved.

I think it's the guy who has to do the work who should get to choose which idea is best.

Jeroen Belleman

The original post listed the constraints, but they were lost over the serial link, and there was no error correction.

I agreed though it didn't seem like any real question was being asked in the first place.

Again with the goofy personality theories! Everyone is hostile to ideas for a few minutes in the evening, when it's time to sleep.

That's normal, and has nothing to do with a career path.

No sane conscious mind is 'hostile to ideas' in any more general sense; that would be pathological, like being hostile to one's own body parts.

Almost all of which is completely wasted. Your proposal of send it three times and vote best out of three being amongst them.

There is just about enough space to do what the OP wants but whether or not they have the mathematical sophistication and programming skills to implement it quickly enough to be useful is still an open question.

You have that *EXACTLY* backwards.

If you cannot adequately describe the exact problem that you are trying to solve then you will spend vast amounts of effort solving the wrong problem(s) again and again. I have seen it happen many times.

Half the battle is specifying the problem and any hard constraints so that proposed solutions will actually stand a chance of working on the available hardware and quickly enough to be useful.

If you have a lot of ideas, one will be the one you use now and the rest are exercizes in thinking, but not wasted. Unless you think that thinking is always painful hence should be minimized.

Your proposal of send it three

It's not a bad suggestion to a poorly defined problem with, apparently, limited logic resources.

Well, I don't hire (or keep) people who are hostile to ideas. Maybe you prefer them.

You have that *EXACTLY* backwards. A reasonable period of confusion and reconsideration is greatly beneficial to design.

Wedge-heads hate uncertainty so latch on to the first, usually textbook conventional, architecture they can find, and implement klunkiness.

I have seen it happen many times.

Half the value is inventing something original that the competitors haven't already made unprofitable. No, 5x the value.

Good engineers routinely implement a specified idea with constraints, first pass if they are really good. Implementing dumb ideas is, well, dumb.

Really? I never noticed that.

Oh, lots of people are reflexively hostile to new or unconventional ideas. Those personalities poison brainstorming sessions.

I'm way more in JL's camp, although not 100%. (I do more math than he does.)

Of course you don't want to take the first thing that comes into your head and build that--nobody's advocating that here AFAICT. I've seen it a lot in the wild, though. In fact, one outfit I had to deal with (a CE in Orange County CA) kept ignoring advice that was backed up with detailed mathematical analysis and a _working_prototype_ of what they were supposed to build. (That transcutaneous blood glucose thing again.)

They just trying things randomly until they ran through the client's money and then quit. One time when I pinged them about it, a bright lad smiled and said, "That's engineering!"

Riiighhhtt.

But a lot, a lot of people seem to have very little emotional tolerance for being in a state of uncertainty. I can't prove that, but over and over I've seen folks spend far too little time turning the problem over in their minds, talking at the white board, and so on, and just charging in and doing the first thing that seemed plausible.

That's super dumb. At the beginning of the process, you have to cultivate offbeat ideas, because (at least in the sort of gizmos I build) there's usually some way to do the task much better and/or cheaper than what's out there.

In general you should spend something like 10% of the time figuring out what you should build, and the rest designing and building it. Skimping on the one very often leads to poor results on the other.

Cheers

Phil Hobbs

The problem is that folks don't want to answer the question posed. They all seem to think the person posing it doesn't understand HIS OWN PROBLEM SPACE and must rely on *them* to explore it on his behalf.

Or, they are incredibly under-challenged in their own work and rely on others for mental stimulation.

Assume the person is competent as an engineer, but may lack "experience" in a technology that he has an inkling MAY help him with his problem.

No one bothered to ask the NATURE of the 14 byte messages! Maybe the OP is a total idiot and has been sending "DATUM_RECEIVED" and encountering DATuM_RECEIVED (1 bit error) DBTUM_RECEIVED (2 bit error) Maybe there is no "NOT RECEIVED" message and that condition is indicated by the *absence* of a message in a particular timeframe. etc.

Not very likely, so why bother to inquire? Yet, there may be changes that *could* be made to the message content (or frequency) that would benefit the OP. Shouldn't the OP be asked to provide further details, there? (rolls eyes)

Or, maybe suggest a different transmission medium!

Or...

Ans: Assume the OP has the skillset (or constraints) to know what he can/can't get away with in his application. And, is EXPLORING the idea of using an ECC to reduce his susceptibility to errors corrupting the transmission.

"Valid" (IMO) comments and questions would then pertain to *qualifying* any solution you might want to suggest. E.g., "What is the nature of the noise source". Or, indicating some minimum set of requirements that must be met for your suggestion (or the OPs query) to be feasible.

E.g., had the OP only had room for a single byte addition to the message, then correcting two errors is not possible WITHIN THAT SINGLE MESSAGE FRAME (because you can only indicate 2^8 "conditions" with a single additional byte and there are 1+112+(112*111)/2 possible "conditions" in which a message can be received with 2 or fewer errors (assuming exactly 112 bits are actually received -- what if he only gets

OTOH, a 2-byte ECC can easily cover that number so *suggests* a code MAY exist (whether or not it is practical to the OP is a different issue).

The exact distribution of errors (and how errors manifest) *in* the data stream is then the important issue.

But the OP has specified a SPECIFIC problem. Whether that will solve HIS "greater" problem is, presumably, something that HE can sort out.

Or, can pose additional queries to gather the information he needs to make that resolution.

Why do folks think they need to know the whole problem in order to contribute to a specific request? Gotta wonder what life was like for these people growing up:

"Mary has 6 apples. She gives two to Francine. How many apples does Mary now have?"

"Why apples and not bananas? Why only two? Why not split them evenly? Why Francine? What about Bruce, Francine's brother? And, are you sure Francine can eat apples? Or, that she actually wants them? Maybe she'd rather have that nice pink ribbon that Mary is wearing in her hair? Are you sure the apples are ripe? I thought Mary and Francine weren't on speaking terms after that incident in the playground..."

Must be dreadful engineers.

Competence usually weeds out "goofy" ideas. Only fools would entertain them (and, they'd only "entertain" them "for ENTERTAINMENT value". And, you wouldn't want to employ folks who can't sort these ideas out before passing from grey matter to vocal tract!

An idea that is outside the box isn't goofy, it's just unconventional. THOSE ideas can cause people to think in different directions towards a *possibly* practical solution.

But, goofy is just plain goofy.

Yes, I work more by instinct and simulation. But my world is largely nonlinear, where the math is basically impossible.

Yes. Uncertainty makes many people uncomfortable, so they lock down an architecture as soon as they can. I've seen horrors.

Brainstorming and a period of confusion can often greatly simplify the design, or add nifty features. It's well worth the tradeoff.

Design is a partly emotional process, which lots of engineers don't want to admit either.

My customers often don't know what they actually need... but they think they do.

Sometimes customers don't know what electronics and signal processing can do for them.

Sometimes experience is the worst teacher.

All wrong. I prefer to employ people who don't censor themselves, who aren't afraid of possibilities.

One of the guidelines to good brainstorming is to not separate serious from goofy from outright jokes. It works.

The solution space is huge, and good ideas might be hiding behind silly ones.

One time long ago, I was in a two-day class for OS/2 Presentation Manager programming. (I did say it was long ago.) ;)

At one point, the presenter (who was actually very good) asked us two questions: Is design an art or a science? What about debugging?

Just about everyone said that design was a science and debugging was an art. That's backwards.

A design is done when the designer says it's done, generally including a good long list of checks for performance, DRC, EMI, ROHS, MIL HDBK 217, ad nauseam. There are nearly always a ridiculously large number of different ways to do the job, if you count all the combinations. That makes it an art.

On the other hand, troubleshooting is definitely a science. There's a problem someplace, because this item doesn't behave like the N previous ones that worked. You find it by applying critical tests and reasoning about them, and when the problem is found and fixed, everyone can agree that it's gone.

Debugging first articles is a bit of both, because you often find design screwups (hopefully minor). In my world that often includes layout-dependent stuff such as how high a current can you run through your 12 GHz pHEMT or 45-GHz SiGe BJT before it becomes unstable. Swapping out jumpers for beads, tweaking current sources, that sort of stuff.

In rare instances it's something really stupid such as upside-down power supplies on an op amp, but normally the first articles are shippable with maybe a roach wire or two.

We have had the occasional disaster, such as a small module with three SMPSes on it to make several rails from a +24V wall wart. The negative rails were made by an AOZ1282 async buck running off the output of an LMR23630 sync buck (+13 -> -12 and +24 ->+13, respectively).

The A-O part is generally super well behaved, but the two together produced a _ridiculous_ selection of high harmonics of the LMR23630's

With that one, we just cut our losses. ;(

Cheers

Phil Hobbs

After some years, we have evolved procedures that mostly prevent getting V+ and V- swapped on opamps.

We recently had an LTM8078 "Silent Switcher" screaming at us in 400 MHz bursts at 2.5 MHz. The embarassing part was that the customer discovered it. Oops.

A nice ancient National 50 KHz Simple Switcher fixed that, with a board spin of course. And gigantic inductors.

I've had good luck with the 150 kHz ones too, with Schottky catch diodes to prevent current spikes from PN diode recovery. They do tend to need chunky inductors to handle all those voltseconds.

Cheers

Phil Hobbs

For those of us who haven't experienced poisoned brainstorming sessions, describe the 'hostility'. I have grey hair, but cannot recall ever meeting someone who was 'hostile to ideas' in general.

a look-up table. how much resources do you have?