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Re: Membership renewal problem ....
Peter: You could simply: 1: ?set up a new yahoo account, 2: become a member of the LTspice group, 3: set the group preferences to send email to a different email account
I found this to better for me, as I rarely use my yahoo account anymore. Another key to this is to be sure to keep the user/password of the new account somewhere as to be secure, and accessible (suggest KeyPass).
On Tue, Dec 17, 2013 at 3:12 PM, Peter Kapas <pkapas@...> wrote:
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Membership renewal problem ....
In last days I faced to a problem to renew my LTspice group's membership. Simply, I am not a member right now, because Yahoo canceled my account, like inactive (?) and for renewal is asking for a cell-phone number (for verification ?) What happens, if some one has no cell-phone, or does not want to by a new one just for that reason. Honestly, I do not want to give out my cell-phone number for the public, for future selling it for advertisement reason, how the companies frequently do it. How to become again a LTspice member? ... Why do I mention it? So, if I read reactions, "see ... this and this letter/folder on the LTspice group's website" I doubt I will be able to do it in future or other with same problem. Is there a different way to enter into this group's website? Thanks, Peter |
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CIC unstable output
?Hello I need help in making a stable output from a CIC interpolator in .TRAN. It works well for a few periods of the input signal, but then it goes exponentially noisy. The settings seem to be extremely influenced by the clocks' dely and rising time, but the integrator stages also multiply any bit of error, too. I wanted to make a list of the things I tried but it seems to strech for too long, so I'll just say that I've tried clocks with voltage sources only, A-devices only, combined (to benefit from tripdt), I tried adding a S&H between the 6th and 7th integrator stage (by that stage the samples simply aren't "straight" anymore and it's about there that the spikes get visible), then between other two stages, then between every integrator stage (a pain since the sample clocks need to be delayed for each S&H), I tried an alternative upsampler with B-source [V(upsample)*V(comb8)], w/out S&H, before and after the upsampler, I tried using B-sources as combs and integrators with proper .FUNCS defined, I tried fiddling with td and tr (delay and rise time for clocks), I simply cannot make this any better than its current state. So I'm asking you: do you know any methods for improving the outcome of this? To be able to run it for 100 (or more) periods of the input signal and not have distortions? Before answering, you should probably try and test your solutions, every new idea I had seemed good before it got put to use. I uploaded CIC.asc in Temp. Anticipated thanks, Vlad |
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Re: LTspice Install problem under linux
Hello keantoken,
> have never EVER gotten the LTSpice web update to work in Linux, in any distribution. The web update of LTspice is working since many years and practically all Linux distributions with WINE. I have updated LTspice many times with LINUX. The last time was a few weeks ago with Ubuntu. Best regards, Helmut |
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Re: LTspice Install problem under linux
¿ªÔÆÌåÓýHi AllI just successfully did the latest upgrade to 4.20g. LTspice on Wine on Ubu 13.10 amd64. So far, ive never had any upgrade difficulties. I wish that every thing went so smoothly. I wish that i had a clue to help you. Al D. On 12/17/2013 02:54 PM,
keantoken@... wrote:
-- AC2CL I do not think there is any thrill that can go through the human heart like that felt by the inventor as he sees some creation of the brain unfolding to success... Such emotions make a man forget food, sleep, friends, love, everything. - Nikola Tesla |
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Re: FFT Resolution
?
toggle quoted message
Show quoted text
No it is not useless, because all FFT algorithms
have errors because necessarily the precision of the floating point arithmetic
is finite. There are many such FFT algorithms all based of discrete Fourier
transformation. The computation yielding transformation from time domain to
frequency domain - the spectrum- requires complex number arithmetic thus one has
so tos speak a double limitation?due to?finite precision of floating
point arithmetic. Especially a pure sine has a very narrow Fourier integral thus
requires precision far above the precision of a for ex. double variable
type.
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Re: LTspice Install problem under linux
Actually, I don't know the developers, but my impression has been that WINE tries its best to merge the Windows window manager with the Linux window manager, so that linux and windows apps will cooperate nicely among each other. There are limitations of course, but it's believable to me that WINE may include linux programs in the list of open windows available to Windows programs. I have never EVER gotten the LTSpice web update to work in Linux, in any distribution. It may have worked a long time ago, but I just download the new .exe when I want to update. |
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Re: FFT Resolution
It is also really important to have compression off! Jim Wagner Oregon Research Electronics From: "John Woodgate" To: LTspice@... Sent: Tuesday, December 17, 2013 11:20:02 AM Subject: Re: [LTspice] Re: FFT Resolution In message , dated Tue, 17 Dec 2013, |
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Re: FFT Resolution
John Woodgate
In message <l8q4um+1ikvaao@...>, dated Tue, 17 Dec 2013,
ronw6wo@... writes: I am a simple soul? ( BTW maybe we are both Brits )I am, I don't know about you. (;-) The height is just the voltage; not infinite. The width would be zero if the sine-wave started at the Big Bang and went on till the Big Crunch. A sine wave of finite duration doesn't have a precise zero bandwidth. Having said that, if you do a FFT on exactly a whole number of cycles, the result is the same as for the truly infinite-duration signal. But since it is a digital process, the apparent width of the line is limited by the bit-depth. Similarly, the line width in an analogue Fourier analysis is limited by the settling time of the analogue filter. The FFT can give useless results if it's not set up correctly. That's why I spent some time trying to get a clear statement of the process. I've now filed that for future reference: LTspice FFT resolution settings To get x Hz resolution, you should, in practice, simulate for 2/x seconds. You can simulate for longer to get a clearer spectrum display, say N/x seconds. To get a spectrum up to X Hz, you then need more than 2*N*X/x samples, preferably the next higher power of 2. -- OOO - Own Opinions Only. With best wishes. See www.jmwa.demon.co.uk Nondum ex silvis sumus John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK |
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Re: FFT Resolution
ronw6wo?wrote, "
It will have finite height, not infinite. ?The finite height is related to the amplitude of the sine wave.
Zero width isn't quite true either because the FFT is discrete in the frequency domain. ?Ideally (when done properly) it will "fill" only one "slot" in the frequency domain and not the adjacent slots. ?In that sense, your intent is probably correct; but it technically isn't zero width.
"What I have seen in LTPSPICE is far off and essentially useless"
Then perhaps you should try Mike Engelhardt's sinewave FFT example in LTspice's Help pages. ?Start Help, go to: ? Waveform Viewer > Waveform Arithmetic and scroll down to the bottom. ?Notice that there is one narrow spike in the FFT's spectrum. ?He uses a SPICE Netlist, but it's almost a no-brainer to replicate that as a schematic. ?Or you could type it in as a Netlist (LTspice accepts those too).
Regards, Andy |
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Re: Transformer
? "This is documented: in the Help"
Specifically, start LTspice and go to Help Topics. ?Then, go to F.A.Q. > How do I simulate a transformer?"
? "Look in the message archives ('All Files') on the list's web page."
The key to the extensive collection of files and models and examples we have here in this group, is the "Table of Contents" listing. ?Start in the group's Files area (), then the "Tables of Contents" folder, then download "all_files.htm". ?Open it in your web browser and search for terms such as "transformer" and "XFMR".
You could also search through the Message archive ("Conversations" tab at the group's webpage) where you will find more to read about transformers than you could probably manage. ?(Hint: The message Search tool is at the top of the webpage, thanks to Yahoo's "Neo" web design.)
When you joined this group, you ignored the instructions that were there on the group's main webpage. ?Go back now, and read what you should have read then.
Andy |
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Re: FFT Resolution
¿ªÔÆÌåÓýYour second assumption is wrong.? An FFT is a finite-length, discrete approximation to the continuous time Fourier Transform.? Read about windows perhaps starting with
? Because the FFT is finite-length, you always have some window function whether you like it or not.? ? ? From: LTspice@... [mailto:LTspice@...]
On Behalf Of ronw6wo@...
Sent: Tuesday, December 17, 2013 10:29 AM To: LTspice@... Subject: Re: [LTspice] Re: FFT Resolution ? ? Good Day? John? ? I am a simple soul? ( BTW maybe we are both Brits ) If one conducts an FFT on a pure sinewave in theory there should be a single spike of infinite height and zero width.? The more the spike departs from those unattainable ideals shows the accuracy of the process.? ? What I have seen in LTPSPICE is far off and essentially useless? ? I hope to be shown the errors of my ways
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Re: FFT Resolution
Please define "far off" and "essentially useless". I have not found either to be the case. Jim Wagner Oregon Research Electronics From: ronw6wo@... To: LTspice@... Sent: Tuesday, December 17, 2013 10:28:47 AM Subject: Re: [LTspice] Re: FFT Resolution Good Day? John? I am a simple soul? ( BTW maybe we are both Brits ) If one conducts an FFT on a pure sinewave in theory there should be a single spike of infinite height and zero width.? The more the spike departs from those unattainable ideals shows the accuracy of the process.? What I have seen in LTPSPICE is far off and essentially useless? I hope to be shown the errors of my ways |
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Re: FFT Resolution
Good Day? John? I am a simple soul? ( BTW maybe we are both Brits ) If one conducts an FFT on a pure sinewave in theory there should be a single spike of infinite height and zero width.? The more the spike departs from those unattainable ideals shows the accuracy of the process.? What I have seen in LTPSPICE is far off and essentially useless? I hope to be shown the errors of my ways |
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Re: Transformer
John Woodgate
In message <1387289159.13459.YahooMailNeo@...>, dated Tue, 17 Dec 2013, Salut Frank <franksalut@...> writes:
Look in the message archives ('All Files') on the list's web page. But it would help if you said what sort of transformer - 50 Hz, SMPS, audio, RF? -- OOO - Own Opinions Only. With best wishes. See www.jmwa.demon.co.uk Nondum ex silvis sumus John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK |
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Re: LTspice Install problem under linux
Business Kid
Er, un-say all of that. It objects strongly to not being on a hard drive. A usb key isn't good enough.On 17 December 2013 15:36, Business Kid <business.kid@...> wrote:
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Re: LTspice Install problem under linux
Business Kid
Separately filing a bug report.
Well, I found I had a binary from? October, and that installed painlessly, so my issue is solved, until they ask me to try the new version on linux :-/. On 17 December 2013 10:05, Business Kid <business.kid@...> wrote:
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Re: Transformer
¿ªÔÆÌåÓýThis is documented: in the Help you have everything to make a basic no-frills transformer.And there there is everything you wanted to ask about transformers but never dared. . Le 17/12/2013 15:05, Salut Frank a
¨¦crit?:
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Re: LTspice Install problem under linux
Business Kid
Thanks, guys. Under linux, life is slightly different. Unless I am running an m$ program already, wine is always rebooted. There is this "wall" between 'windows' and linux and the idea of windows barfing over the title on a linux browser seems far fetched in this instance - wine has it's own IE. I will check.On 17 December 2013 07:15, <helmutsennewald@...> wrote:
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