Marko Rodin Coil -- 007 Device

[picowatt]

As long as there are no vibrations,an ideal square wave is achievable.


Brad

"Ideal" of course meaning a square wave with infinitely fast rise and fall times (instantaneous) perfectly damped (no under/over shoot or ringing) containing an infinite number of odd harmonics...

PW

[MileHigh]

Yes there is,, you are smart enough MH,, you might be able to figure it out,, it did take me a while to figure it out,, but I am not the sharpest tool in the shed

Just give me an example of what you believe is a perfect square wave in the mechanical world and I will then see if I can argue it out.

[tinman]

Just give me an example of what you believe is a perfect square wave in the mechanical world and I will then see if I can argue it out.

Yep--always after one.



Brad

[tinman]

This is an "argument" that I would be interested in seeing....

I have a very old problem with the "Wonderful" concept of "adding" together sinewaves to create the square wave.  (Well, merge, not Add.)  Simply put, it is really a math "Cheat".

Before ANYONE bothers to try to change my mind, realize that I had this very argument with very smart people decades ago, and my opinion will not change.

Both sides are CORRECT and there is NOTHING that will change that.  For a simple reality check, think of basic digital computers and digital logic that can create analog waveforms.  Are you doing this by adding together squares to construct these outputs?  (If so, apply for the Nobel...)  Any digital computer cares not for the harmonics as they don't exist in software, except in our thought when programming.  The processor knows not.

By the same token, there is NO denying that FFT works, and is very accurate.  For me it is still a math cheat, as math has many severe limitations.  This is not to say that "Looking" at the FFT method and realizing that such is possible isn't a fantastic analysis method.  There are always two ways of "Seeing" something.

For example, the simplest math problem.  Take 1 and divide by three.  Write down that value. (How ever you want as long as it's NOT as an equation, but a number.)  Multiply this number by three.  I hope this begins to explain what the REAL problem is.  There are many "Cheats" in math to get around this problem but the end result of the basic test is math doesn't always work in the way that one thinks.  It is ONLY our looking at it with intelligence that shows these problems.   Dealing with computers all the time slaps me in the face this way too often for me to ever accept (easily...) what is "proven" by math.  I will always need to see the actual physical device in operation to believe it.  (Accurate testing with proven equipment and ALL specs "might" be an exception...)

As you can imagine, I lost a LOT of respect for fellow engineers during those olden days while having to plow through calculus for multiple years.  Just because I fully understood it and always got an "A" doesn't mean I ever willingly used it nor ever hope to.  The mind can do more than the math for the basic understanding.  Then again, once into the "details" and testing of specific things, the math is a necessary evil, but I doubt Ottoman did major flow calculations before trying the 1st design of the 4 stroke engine, etc.

Of course, without FFT, and all the advanced signal processing that it has already provided, we wouldn't have half of the great things we have.  Cell phones haven't had analog transmitters or receivers in quite a while.  That is just ONE example out of thousands.  (CD's, DVD's, the list is too long....)  Just because something is a "Cheat" does NOT mean it doesn't work...

All I want to really say is:  A square wave is just that, if looking at it digitally.  For a SINGLE rise, as was initially mentioned, the harmonic content has no bearing or application.  Same with a single pulse, as the same concept applies.  Make it at all repetitive and that all changes depending on what you are doing with it.  If said square wave is being amplified and sent out as a signal with a purely digital reception, then who cares.  Send that same signal down a transmission line to get there and, NOW, you have a different situation and such things become important.  Feed ANY square wave into, say an audio amp, and you are really into the analog realm and such analysis becomes the MOST important.  Am I making sense to anyone?  Are we there yet?

So, in the SIMPLEST form, an Ideal voltage source, short wire to Relay coil, the relay turning on will not be concerned with the harmonic content of the rise of the wave, if it really exists...

Also, in the simplest form, same source, long twisted pair wire to transformer primary with secondary to audio amp...  You need a lot of math to really figure the responses accurately...  Here is where I have trouble, I would prefer to measure it at that point instead of calculate it.  There are many times things you didn't think of that the math will not expose.  Testing will.  FFT analysis will not mention that the cover happened to have a metal clip that altered the transmitters function, nor that the cover being loose will cause the "unknown" fix to be intermittent.  Math IS NOT physical.
(Even IBM designers, back in the day, were creating twisted pairs with a drill and actually testing response of different turns per inch instead of calculating what the best would be as the math just wasn't good enough at that time.  Effects of tightness of the twists was not fully known.   Yes, I was there and saw it for myself.  Now, twisted pair ethernet is common.  But, they also made the "?" circuit that took a basic crystal at 12.0000 Mhz accuracy and digitally made it 12.0000000000 Mhz accuracy.  I still believe that put the digital TTL logic into the analog realm, done digitally.  I was not privy to details but I do know that some heavy math was used, in a digital circuit?  At the time, this was all cutting edge stuff.  Talking late 70's.)


So, Please, Argue away as a lot has been changed over the years and I enjoy learning new things but both sides must eventually accept that math requires cheats and there is a reason that electronics (as well as physical devices) are called digital and analog.  The hard part is accepting that Digital electronics can used used in an analog manner and that vice versa also applies.  The application determines what you are dealing with and no one method covers ALL applications.  (To qualify that, you could use a slew of FFT to process a single rise time to a large inductor from the voltage, but why would anyone ever bother to make something so simple be such a pain in the butt?  To someone stuck in the math zone or putting on airs, OK, but to a real bench worker, you must be kidding.  Lets get into the real world for a bit.)

Be happy no one mentions quantum theory as the debate gets even worse.  (I didn't write that, someone else did...)

It is good to have some one like your self here on this forum Loner

There are many cases where this harmonic sine business is stretched beyond any practical purpose.
There are also cases where it simply dose not exist,and in some mechanical cases as well.
The binary code it self has no sine harmonic--it is either a 0 or 1--nothing in-between.
A simple drawing of a square wave on a piece of paper has no sine harmonic.
In the mechanical world,a dog clutch would resemble a square wave actuator--it is either in ore out of gear. Any vibrational harmonics that come after the engagement have nothing to do with the engagement of that dog clutch it self-->even the teeth of the clutch resemble a square wave with no sine harmonics. Now a cone or plate clutch could be seen to resemble a sine wave,where full engagement can build over time,but as i said,a dog clutch is either in or out. Most of the outboard motors used dog clutches,unless you opted for something like the johnson/evinrude selectromatic's,or the inboard velvet drives. Other than that,it is either in or out--no in-between.


Brad

[tinman]

Ideal world???

Torque,,

Real world,,

Pulsed Constant torque.

There is nothing to debate really,, for a given constant torque being applied it is either on or off.

Levers on the other hand do not work in a linear fashion and so have a rate of change of force,, something that must accelerate or decelerate.

The simplest of simple,,,, a string wrapped around a pulley,, pull on the string but do not let the pulley turn.

Are,but the string will oscillate up and down when pulled tight. This will cause an oscillation in the torque value--although very small,it is still there.


Brad