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Thread: What is rise time?

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    TM: Administrator Chat with me Peter Walker's Avatar
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    Default What is rise time?

    In a perfect square wave the amplitude would rise from zero to maximum in zero time. However we live in the real world - to do this in reality would require a perfect system with infinite energy! So in real systems we can never create a perfect square wave and it takes a certain finite time for the amplitude to move from zero to maximum. This time is called the rise time. This is a simplified definition because engineers use a more rigorous mathematical description which is not quite the same thing, but you can consider it in the way described to get an idea of what engineers are talking about in general. The faster the rise time, the closer you are to a perfect square. The reverse of the rise time (the time taken to fall from maximum to zero amplitude) is called the fall time.

    Engineers working with modern Rife type machines tend to aim for the fastest rise and fall times possible in practice because this gives a greater content of very high frequency harmonics which may be beneficial to the biological effect.

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    Default Re: What is rise time?

    It would be really helpful to have some specifics re the rise time so I know what to look out for in the data sheet of a FG to assess the rise time and also what would you consider to be an 'good' rise time opposed to a 'poor' rise time.

    Gratefully
    David

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    † Deceased † Chat with me Francois Lemettre's Avatar
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    Default Re: What is rise time?

    Hello ,

    "Rise Time" and also "Fall time" are explained at the page 2 of 10 in this pdf :
    http://www.fairchildsemi.com/an/AN/AN-77.pdf

    - Look at "figure 3".

    A small rise and fall time is ideal.

    It you want to choose beyong the TTL componant series like 74xx , choose 74Fxx

    F = Fast.

    Regards,

    François.
    Last edited by Francois Lemettre; 02-20-2010 at 21:06.

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    Danielle Chilton (02-20-2010)

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    Default Re: What is rise time?

    Hello,
    Rise time is the time taken by the electrons "at rest", in a random movement to their cooperative snail movement in the metal. It depends on many parameters, one nanosecond is excellent.
    Best regards

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    Default Re: What is rise time?

    There is a gallium nitride monolithic half bridge chip that achieve this nanosecond, but is important to place driver close to output device, other ways is not used.

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    Default Re: What is rise time?

    Rise time steepness is the second derivative. The third derivative is it's acceleration or jerkiness or perhaps pointiness. I think it also relates to a thermodynamics theory about energy transformation to pressure oscillation, aka acoustic energy. You might predict a pointy modulation will attenuate the wave faster than a smoother one. In square waves, I was told more pointiness generates higher harmonics than smudged corners, even where rise time steepness can be high in the latter.

    If the RF propagates much faster than any child acoustic phenomena, can the latter form a plane wave front ? I don't think so. I apply the word discontiguous here ... With a g not an n. But I might be wrong ...

    A spike can be even more pointy that a square form.

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    Default Re: What is rise time?

    Alan,

    First, maybe a rule of departure point, you gotta mention the fundamental principle before you go off on derivatives. What is the principle here ?

    Secondly, in terms of thermodynamics,you get 'post of the year' for that one. I think the thermodynamics theory that you mention has great merit.

    When you loose RF propagation at the speed of light and bring in acoustic pressure propagation the wavelengths that we are concerned with come 'more' into proper order for our Rife studies.They go from extending 80 meters long to rather appearing as flexoelectric.

    But I do not understand your mention of "plane waves". I was more thinking longitudinal wave actions.

    Then you mention that a spike can be more pointy than a square form and yea, you have to build your wave with purpose and the spike provides band-pass properties needed, but the square adds an awesome set of following additive energy, so howabout a spiked square waveform ?

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    Default Re: What is rise time?

    Plane just means not curved. It could easily be curved, same deal.

    In regards to second and third derivatives, I am not an expert. I hoping some other person here can educate us more. Lin wrote on this subject , if readers want to study this. Try Lin microwave hearing in pubmed search or another academic search engine that picks up physics publications. Thats a fun subject.

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    Default Re: What is rise time?

    This might be a moot point. Essentially all the variables are decided at the point of materials selection. Engineers choose the materials based on their LCR (inductive/capacitave reactance) physical properties. Once the materials are selected, the rise time cannot be altered, except external influences like supercooling, or better sheilding in the packaging, or optimizing component and conductor spacing, as well as conductor connectors. Connectors are always suspect. Careful circuit analysis often finds connectors make an optimum circuit a lot less than optimal.

    Once designed and components assembled the rise time on a pad device will remain the same for its service life. I have switched to gold plated 4mm banana plugs and sockets on pad devices, because when measured with a TDR (time domain reflectometer) I could see the impedence of the non-gold plated sockets and plugs were not great. Then careful circuit analysis can uncover problems like cold solder joints. We tend to look for much more serious problems, but often it is as simple as a cold solder joint.


    On a plasma device, the particular tube rise and fall times are determined when manufactured. Later once designed and constructed there is little that can be done to change it. LCR can be altered by spacing conductors to minimize reactances, when constructing the device. This is only the delivery to the plasma tube. So rise time/fall time is what it is, and the result of decisions made before we get our hands on it. It is an interesting discussion, but many of the material recommendations are historical/empirical and only change with the development of new technologies. Phil
    Last edited by Philmore Rial; 11-28-2020 at 23:25. Reason: added cold solder joints

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    Stanislaw Chmielarz (11-29-2020)

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    Default Re: What is rise time?

    Quote Originally Posted by Alan Blood View Post
    Rise time steepness is the second derivative. The third derivative is it's acceleration or jerkiness or perhaps pointiness. I think it also relates to a thermodynamics theory about energy transformation to pressure oscillation, aka acoustic energy. You might predict a pointy modulation will attenuate the wave faster than a smoother one. In square waves, I was told more pointiness generates higher harmonics than smudged corners, even where rise time steepness can be high in the latter.

    If the RF propagates much faster than any child acoustic phenomena, can the latter form a plane wave front ? I don't think so. I apply the word discontiguous here ... With a g not an n. But I might be wrong ...

    A spike can be even more pointy that a square form.

    I think you are right but it is intuitive. Meisner Field in the third ventricle from superconductive DNA. A quantum event horizon between Delta Q (memory location) and consciousness. This is difficult to pay attention to without the conclusive comment by Dr Richard RESTAK in his Great Courses series, Optimizing Brain Health:

    What could be more important than your ability to reestablish contact with your emotional memory?
    The Meisner Field is collectively generated by monatomic gold in 2-dimensional flux but for most of the spike clusters of gold are formed. Whenever the tip top of the spike is so small as to form metallofullerenes of monatomic and duatomic gold that is the deepest penetration through the soft palate in the roof of the mouth. So the monatomic gold is placed well within the third ventricle and Aqueduct of Sylvius. This is where it enhances intuitive judgment and emotional balance.

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    Do you see how the current spikes through the elite shungite, already loaded with transition metallofullerenes and through palladium and gold, in the photo to deliver specified metallofullerenes at the top of the spike?



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    Last edited by David Merrill; 01-01-2021 at 01:10.

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    Default Re: What is rise time?

    Hello,
    I was one of the oldest fullerene and nanotube maker. I remember drilling carbons rods to include metals in the arc vapour of carbon;
    Really there are ways to play on rise time, the real problem is the tube and the speed of ions and electrons, and here the deal is the voltage, and the energy you impulse to the moving particle which finishes to ruin the tube.
    Best regards

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    Default Re: What is rise time?

    Quote Originally Posted by Jean Mareche View Post
    Hello,
    I was one of the oldest fullerene and nanotube maker. I remember drilling carbons rods to include metals in the arc vapour of carbon;
    Really there are ways to play on rise time, the real problem is the tube and the speed of ions and electrons, and here the deal is the voltage, and the energy you impulse to the moving particle which finishes to ruin the tube.
    Best regards

    Thank you for sharing your vast experience.

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    I have to live with the rise times that I have. Now I have much better graphics with the DSO. I found a photo where you can see the spikes. Once the Meisner Field is collated there is no need for further treatments.

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    Default Re: What is rise time?

    Hello,
    Is it shungite pads? Sliced and polished shungite? At the begining we ignored completely the presence of natural fullerenes. I remember my first NMR of the extract in toluene. There was a single peak, but I had not much.
    Best regards

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    Default Re: What is rise time?

    I am bothered by unknown ion pumps - especially should they contain aluminum. So you might think it very inefficient compared to the lab or fabrication process you have done.
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    Here are two ion pumps - but the invention is Doped Carbon 60 Nanoparticle Pump.

    For the fannypack rendition I mixed up a shungite monatomic gold broth and packed latex rubber on the factory electrode. It was black and rubbery so I suspect they were using carbon 60 but when I asked they were silent. No surprise.

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    Default Re: What is rise time?

    Hello,
    Usually ion pumps électrodes are made of metals like titanium which are able to react with most ions such oxygen, hydrogen, nitrogen, argon. Aluminium is not always very efficient for ionic implantation which is the pumping mechanism for noble gases. Fullerene is curious in an ionic pump as it can be distilled in very high vacuum (I did it for purification purposes and also to grow crystals in collaboration with a russian team). If you suspect the presence of fullerenes you can extract with a few toluene, they are fairly soluble in this solvent, around one gram per liter. One gives a yellow color, the other purple, I dont remember which. Have you some advertising on such pumps? I know people dissolve some C60 in olive oil, which is very long, and put it in mouth.
    Best regards

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    Default Re: What is rise time?

    Quote Originally Posted by Jean Mareche View Post
    Hello,
    Usually ion pumps électrodes are made of metals like titanium which are able to react with most ions such oxygen, hydrogen, nitrogen, argon. Aluminium is not always very efficient for ionic implantation which is the pumping mechanism for noble gases. Fullerene is curious in an ionic pump as it can be distilled in very high vacuum (I did it for purification purposes and also to grow crystals in collaboration with a russian team). If you suspect the presence of fullerenes you can extract with a few toluene, they are fairly soluble in this solvent, around one gram per liter. One gives a yellow color, the other purple, I dont remember which. Have you some advertising on such pumps? I know people dissolve some C60 in olive oil, which is very long, and put it in mouth.
    Best regards
    Thank you for the insights. I have activated antigens in my new .5 kilograms of oroxylum indicum stem cell DNA. It is a delicious spice and morning coffee substitute.

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