From: "Terrell W. Fritz"
Date: Wed, 27 Mar 2002 20:36:17 -0700
Subject: Re: Ready :-)) - Re: [TSSP] short H/D and stuff
Hi Paul,
At 11:41 AM 3/27/2002 +0000, you wrote:
>Hi Terry,
>
>Sorry I haven't sent any code over yet. I'm just not happy with
>the program yet. Had to unwind some of the code and redo it, but
>it's getting there.
No problem at all. I am no expert on the Sun UNIX stuff but I think I can
figure out the compiling and stuff. With 600+Meg of ram and 64 bit processing
it should be able to do the math :-))) It's more powerful than all my other
computers combined!! Oddly, it is also the least expensive computer I have...
>Still have to think of a name: did consider
>'Coil Resonance Analysis Program' but decided against.
>Maybe tcma: Tesla Coil Mode Analyser?
>
>Don't worry about the trace captures, they appear to be absolutely
>fine. I have quite a suite of test data files generated by
>software to contain certain mixes of signals and noise. The
>program isn't quite working correctly on these yet.
>
>I'm concentrating on getting 'tcma' working properly first, and
>then I'll go on to do a more accurate analysis of the current
>profile results. I'm tempted to mention the progress so far to the
>pupman list, because the results already achieved demonstrate the
>elevated current maximum very nicely - almost identical to fig 6.1
>in pn2511, and this is very strong evidence that we have quantified
>the internal capacitance correctly, and applied it correctly in the
>model. This feature of solenoid resonance is the main departure
>from the kind of transmission line behaviour described by the
>familiar telegraphist's equation, so it's nice to see it so
>unequivocally demonstrated.
:-)) Excellent!! It also opens a new world of Tesla coil measurements with
this pinger thing!! I wonder what the pinger would reveal on the full coil
setups and such? There is still a lot of potential there for other great
stuff!!
>
>> I will also change the timing to help get higher frequency data.
>
>Well I'm not seeing any problems attributable to the input file in
>this respect. So long as there are 2 or 3 steps per cycle, we're
>ok.
I was pushing buttons and looking at the scope's own FFTs and the following
appeared pretty good:
http://hot-streamer.com/temp/Paul/3-27/TEK00000.CSV
You may want to check it to see if the information there is any better. It is
a 16 average of the no resistance case with different time and scale settings.
The scope seemed to think it was best for the 0-2MHz harmonics. Let me know if
it really is any better or not.
>
>An important thing about the traces is that they contain a small
>amount of pre-trigger. Doesn't need much, but it's important that
>the program sees the start of the event. In this respect the
>existing traces are fine.
>
>> and let the scope average over say 16 waveforms.
>
>Ought to work fine with single shot. Averaging over 16 could give
>up to 4 times improvement in sensitivity, but at the moment we're
>not at all limited by the noise floor. At some point the traces
>will be limited by the Y-axis quantisation noise, so averaging
>beyond a certain number will not help any. At my end, one optional
>technique is to inject artificial noise in order to reduce the
>sharpness of the correlation functions - makes for better initial
>convergence.
The 16 average is just a push of a button so no problem either way. It could
do 512 (or any power of 2) also if that is of any use. The scope has functions
I can't even pronounce... In seven languages too...
>
>There's definately a tiny little resonance circa 190kHz in these
>traces, Q of around 14...hard for the program to lock onto...
>
>3-26/TEK00001.CSV
>PK FREQ kHz (Error +/-) Q FACTOR (Error +/-) LEVEL
> 1 229.940 (0.01%,20Hz) 290.32 (5.23%,15.2) 98.1% -0.2dB
> 2 578.003 (0.03%,187Hz) 162.62 (5.23%, 8.5) 16.9% -15.5dB
> 3 903.931 (0.07%,635Hz) 103.88 (3.92%, 4.1) 7.4% -22.6dB
>*4 201.616 (0.37%,736Hz) 13.91 (25.48%, 3.5) 14.7% -16.7dB
>Accounted for 98.0% of input signal
>
>and from
>3-26/TEK00004.CSV
>PK FREQ kHz (Error +/-) Q FACTOR (Error +/-) LEVEL
> 1 229.958 (0.01%,26Hz) 221.01 (6.04%,13.4) 97.7% -0.2dB
> 2 578.098 (0.03%,193Hz) 152.73 (1.07%, 1.6) 18.1% -14.9dB
> 3 903.931 (0.07%,632Hz) 101.37 (6.04%, 6.1) 8.9% -21.0dB
>*4 185.355 (0.21%,381Hz) 16.12 (25.48%, 4.1) 8.7% -21.2dB
>Accounted for 98.2% of input signal
>
>Have you another coil in the room that's responsible, I wonder?
>Wanders around in frequency quite a bit - maybe it's the pinger
>tank capacitance resonating through the gap circuit inductance?
Let's see:
22nF and 32.65mH resonates at 5936Hz so that's not it. Too high for the HV
supply's SMPS switching frequency. The big coil is fairly close but that does
not seem like the right frequency. The scope is super shielded as to the
cabling and such (the RS-232 module has giant ground fingers all over it :-)).
I can't find it with he Scope's own FFT... So right off, I don't have any idea
what it could be... Perhaps ringing in the long coax I use for a ground...
190 kHz with a 32.65mH coil suggest a capacitance of... 21.5pF that seems far
too little for the 30+ feet of coax... I just can't see anything with that
frequency. I can certainly see the gap to 22nF cap resonance "up there" but
nothing makes sense at 190kHz...
So, I don't know what it is...
>
>> The bucket also has a bottom and a heavy support near the top...
>> The coil sits on a Styrofoam box. It could be suspended by
>> string too.
>
>I should leave things as they are for the moment. No indications
>that these things are having adverse effect, and the stability of
>the test setup is desirable at the moment, while refining tcma.
>
>> I will try reducing the size of the CSV files too. Maybe put
>> them in one file with only one set of timing numbers and ZIP
>> them.
>
>No need. If you like, just zip the directory containing the 12
>(or so!) csv files.
Ok
>
>> I got the RS-232 adapter for the scope... The RS-232 thing came
>> with a big programming book that explains the like
>> 300 commands...
>
>Yeah, they're usually very easy to program. We use loads of
>automated waveform capture stuff at work - I wrote most of it.
>Is the RS232 command set documented on the web? If so I can maybe
>help, but I won't be able to supply code for windows. You can
>probably use windows 'terminal' to manually command the scope, then
>when you've got a sequence of commands that work, just paste them
>into a 'basic' program.
The 433 page tome is at:
http://hot-streamer.com/temp/Paul/3-27/71038102.pdf
There is also a guy on the web who has a real nice application to do this stuff
with the scope:
http://www.metratek.com/
I tried the demo and it works really nice and smooth! I'll probably just get
that. It does all the cool stuff just like it is supposed to be done without
any hassle at all. It even saves CSV files to remote FTP sites every 30
seconds and stuff ;-)) I get the impression that if it does not do something
right, he will just fix it for you... I always like "little guy" programmers
like that :-)) Looks like he has already made the obvious program of my dreams
:-)) The Tektronix WaveStar was designed by some kind of Dilbert committee...
It's super bad :-p Thank goodness they provide a demo so you can see how bad
it is :o)) But this other guy's thing is really nice.
I really did used to do RS-232 machine interface programs in machine language
in high school, but the world was simple and only 8 bits back in the late 70's
:-)) I claim total amnesia these days :-))) However, I do still know enough
to be dangerous, but I know when to quite and just buy it too :-)) They guys
at work were showing me LabView and HP VEE stuff too. Easy to make a one time
program but a "real" application is far more versatile for other stuff...
>
>As regards the Delrin, etc, it's probably premature to trust the
>accuracy of the Q extraction enough to recognise the extra loss.
Cool. Just feeling around to see what would happen.
I'll concentrate on getting the Q vs. weather thing going. It is starting to
get warm here so I would like to go fast on that.
Cheers,
Terry
>--
>Paul Nicholson
>--
Maintainer Paul Nicholson, paul@abelian.demon.co.uk.