Multiple shield frequency, Fourier-transformation

[bz249]

Have anyone in the ST-verse heard about Fourier-transformations, because it seems very strange to me to use a simple harmonically oscillating shield instead of a square profile (with large flat parts and windows, during which the phasers can fire) such a prolile is not really hard to produce, basically composing at maximum five different base frequencies one would have a rather good approximation.

What is the in-universe reason they stuck with the harmonic oscillations?

[FOG3]

I have a sneaking suspicion the Trek writers just wanted to deal with a single number. Much like how the IQ has become, despite the fact original guy developed the metric for analyzing developmentally delayed children, and believed intelligence too complex to be quantified by a single number.

That being the case I doubt there is an official in-universe explanation, anymore then most "why didn't they" questions like with the Caretaker array. You could make something up that sounds semi-plausible, but is it really necessary to make up our own technobabble justification in this case? People are lazy and like to deal with single numbers. It's a well established facet of human nature.

[Fingolfin_Noldor]

Have anyone in the ST-verse heard about Fourier-transformations, because it seems very strange to me to use a simple harmonically oscillating shield instead of a square profile (with large flat parts and windows, during which the phasers can fire) such a prolile is not really hard to produce, basically composing at maximum five different base frequencies one would have a rather good approximation.

What is the in-universe reason they stuck with the harmonic oscillations?

I don't really think they ever thought about things too closely. Fourier analysis is a pretty advanced topic in itself.

Anyhow, one thing that bugged me was why the discovery of pulsed phasers was actually such a great thing considering pulsed lasers were quite well known to deliver high peak power.

[NecronLord]

Presumably reprogramming the shields is a job that needs to be done regularly (hence why the number's on a big display in engineering) even by non-technical people (on frieghters and such) a random number makes sense. For humans and similar, simplicity is a virtue in itself.

Meanwhile, advanced ships like borg cubes have used 'triaxilating modulation' - which, given that it's being done by people who can travel across the galaxy in minutes, we can safely assume is pretty optimal unless shown otherwise - to rotate their shield frequencies.

[RedImperator]

Well, my guess the reason they stuck with harmonic frequencies is that Trek's writers were a bunch of English lit majors who have no idea what a Fourier transformation is (PS, what the fuck's a Fourier transformation?). In-universe, they're probably all morons, hurf hurf, trigger guards.

OK, that out of the way, with what we know about shields, is there an obvious in-universe technical reason why they wouldn't use Fourier transformations? It could be that there's some insurmountable technical obstacle to it. I want to like Necron Lord's explanation, but it seems to me that it would be better just to leave that job up to the computer.

[Simon_Jester]

It could be that the shield frequency is set by the hardware parameters of the shield generator, much like, say, the frequency of AC current coming from a power plant. If the frequency is determined by the hardware then you might be able to adjust it by playing around in the generator with a wrench (or a soldering iron)... but you damn sure won't be able to set the same generator to produce multiple shields at different frequencies, all running in parallel to cover the ship.

[Bounty]

Considering nobody knows how shields work or even what this "shield frequency" number even refers to, isn't the whole debate academic? For all we know the number characters use a simplified cypher spat out by the computer to make input easier.

[phred]

Ever since I found out about Shields and phasers and torpedoes all having frequencies, I've always figured it was necessary to have everything set the same so you can fire through them.
I mean if your torpedoes are at a different frequency from your shields, won't they detonate when they hit? That would probably be a bad thing.

[Simon_Jester]

Well, a torpedo is a physical object with (by all appearances) an impact fuze. You probably don't set it to a frequency at all, any more than you would set an artillery shell to a frequency. You're just careful to make sure your shields are down at the moment it goes through.

[Littlefoot]

Well, a torpedo is a physical object with (by all appearances) an impact fuze. You probably don't set it to a frequency at all, any more than you would set an artillery shell to a frequency. You're just careful to make sure your shields are down at the moment it goes through.

This is a bad way to fire a weapon. It makes more sense to make a weapon capable of traveling through your shields without dropping them. With shields, torpedoes and phasers all being controlled by one computer, it seem plausible that this is why shields and phasers are frequency based. How they get the torpedoes to have a frequency is beyond me, but I am sure the tchno-babulator can come up with a way. This isn't a good reason mind, but it makes sense in a trek way.

[PhilosopherOfSorts]

Yeah, that makes sense if you're capable of doing it, and for all I know that may be the case with phasers, but as Simon_Jester said, torpedoes are physical objects, they don't have frequency to adjust, so the shield probably has to come down for them to pass through. This isn't as bad as it sound, the shields only have to be down for the split second it takes for the torpedoes to pass through, and only in the area they do so.

[bz249]

Yeah, that makes sense if you're capable of doing it, and for all I know that may be the case with phasers, but as Simon_Jester said, torpedoes are physical objects, they don't have frequency to adjust, so the shield probably has to come down for them to pass through. This isn't as bad as it sound, the shields only have to be down for the split second it takes for the torpedoes to pass through, and only in the area they do so.

Not really, thats why they the frequency issue for the first place, they either have a full bubble or nothing, so it is impossible to open "gunports" on the shield. But with a pulsing shield they always have shieldless periods.

But anyway it is not that difficult to synchronize the phasers, shield and the torpedoes... even with current day technology it is quite simple.

[PhilosopherOfSorts]

Ok, so you can't open a "gunport" in the shield, but a physical object still doesn't have a frequency to adjust. How long do think the shield has to be down for a torp to pass through? Yes, there will ba a shieldless period, for a small fraction of a second, then they'll be back up. A very lucky shot might get through in that interval, but I don't think its very likely.

[Batman]

The physical torpedo casing doesn't have a frequency. Whatever mechanism produces the torpedo glow might, allowing the torpedo to pass through the shields (not that they ever explained it one way or the other that I remember).
Personally I always assumed shields are semipermeable-stuff can get out but not in (and no, I don't think they ever explain it that way either).

[bz249]

Ok, so you can't open a "gunport" in the shield, but a physical object still doesn't have a frequency to adjust. How long do think the shield has to be down for a torp to pass through? Yes, there will ba a shieldless period, for a small fraction of a second, then they'll be back up. A very lucky shot might get through in that interval, but I don't think its very likely.

Not much... if they can produce a correct trigger signal. But if they can, why they don't do it with the phasers? Having a regular trigger can be produced, by composing the right frequencies.

[JGregory32]

Why not slap a very small shield generator in the torpedo casing? Give it the same frequency as the shields and trek physics (which say anything on the same frequency can pass through) takes over.

Though the real question then becomes why can't shuttles and runabouts do the same trick?

[Littlefoot]

Why not slap a very small shield generator in the torpedo casing? Give it the same frequency as the shields and trek physics (which say anything on the same frequency can pass through) takes over.

Though the real question then becomes why can't shuttles and runabouts do the same trick?

Quantum

[Mr Bean]

Why not slap a very small shield generator in the torpedo casing? Give it the same frequency as the shields and trek physics (which say anything on the same frequency can pass through) takes over.

Though the real question then becomes why can't shuttles and runabouts do the same trick?

If that's true why are they only use it to get out of their own shields when they could supposedly do the same for the enemy? After all if a shielded torpedo can exit one shield why can't it enter another? Because your own shields frequency changes your torpedo must have to be able to change frequencies. Meaning why not make a good effort to see if you can bypass their shields?

[Stark]

Maybe because shield frequency cannot be externally determined, since they can't match weapons to shields without some kind of exploit? It's easy to match your own frequency because you already know what it is.

[JGregory32]

<Scarcasm>
Damn it Littlefoot! You know there's no way I can refute "Quantum"! It's the ultimate answer!
"Hey, why is my foot on fire?" "Quantum!"
"Hey, why are you sleeping with my girlfriend?" "Quantum!"
"Why have high frequency trading practices that allow for massive profit taking without adding value not been outlawed?" "QUANTUM!"
</Scarcasm>
I do remember a first season TNG episode where Data was able to fly a shuttle through a weak point in the shields but I think that's also the point the rear launcher would fire the torpedo through.

[starslayer]

(PS, what the fuck's a Fourier transformation?)

Let's start with the Fourier series. Basically, the concept is that if we have a periodic function (like a square wave or something), we can instead write it as an infinite series (a sum with an infinite number of terms) of sines and cosines. We can't do this with just anything, though; the periodic requirement is crucial because sines and cosines themselves are periodic. This picture illustrates the concept.

We can, however, turn any function into a periodic one by saying it has an infinite period (that is, it takes an infinite amount of time to repeat itself). Once we do so, we are no longer able to the use the basic Fourier series, however; we must sum up all possible sines and cosines, meaning we have to do an integral over all space, say. We didn't do so in the series because we only used sin(nx) and cos(nx) with n being an integer; here, n can be any real number. Thus ends the probably still confusing math-speak.

tl;dr version: Basically, a Fourier transform is a way of representing a non-periodic function as an infinite sum of periodic ones.

Why is this useful? Well, in signal processing, when you read in a signal on your oscilloscope, you'll see a picture of the signal across time. If you take the Fourier transform of the signal, it turns out that you'll actually see each individual frequency that makes up the signal, as well as the amplitude at each frequency. This would be useful for Star Trek shields because with the right combination and strength of frequencies, they would be able to project any shield shape they wished, and because there is more than frequency being used, tricks like the Klingons used in Generations simply wouldn't work. Given their absurdly bountiful computer power, it should be absolutely no trouble for Federation ships to use this technique, and there is absolutely no real reason not to use Fourier transforms in projecting your shield bubble, if your generator is capable of operating at multiple frequencies at once.

[Fingolfin_Noldor]

We can, however, turn any function into a periodic one by saying it has an infinite period (that is, it takes an infinite amount of time to repeat itself). Once we do so, we are no longer able to the use the basic Fourier series, however; we must sum up all possible sines and cosines, meaning we have to do an integral over all space, say. We didn't do so in the series because we only used sin(nx) and cos(nx) with n being an integer; here, n can be any real number. Thus ends the probably still confusing math-speak.

Caveat. Only a function which is in the L^2 space, and maybe L^1 space may be fourier expanded. Essentially, the function must be integrably finite over the entire interval it spans.

[JGregory32]

If that's true why are they only use it to get out of their own shields when they could supposedly do the same for the enemy? After all if a shielded torpedo can exit one shield why can't it enter another? Because your own shields frequency changes your torpedo must have to be able to change frequencies. Meaning why not make a good effort to see if you can bypass their shields?

You can enter the enemy shields if you know the frequency, that what the scene in generations was all about.
Because the Duras sisters had the Enterprise's shield frequency their torpedos were able to bypass them and directly damage the enterprise.
This scene could also argue for the torpedo's having some method of changing frequency. Unless the Duras sisters changed their own shields to the same frequency then the torpedo would need to change the frequency of its inbuilt shield generator to match that of the enterprises after it had passed through the BOP shields.

[Azron_Stoma]

supposedly, that's one of the possibilities for the much wanked Transphasic Torpedoes in how they get through shields, in which case a shield with no frequency would be hit the same as if by any other torpedo.

in the RPGverse they have something called a "Hellfire Torpedo" which supposedly does that, while Transphasics go in and out of subspace, a simple subspace transceiver mixed with a shield projector should be able to block that.

and if the Transphasics used a similar system of the Phase cloak (only staying visible somehow or phasing/dephasing only when "impacting" the shields and armour) then using tractor beams as point defense or generating a massive/intense field of Anyons in front of the shields as an additional layer would work against that.

[Darth Wong]

In order to use this technique, it must be possible to superimpose waveforms. Therefore, one obvious in-universe reason why they can't use this technique would be that you can't superimpose shield waveforms. The fact that something can be described as having a frequency does not mean that it must be like an electronic waveform on an oscilloscope.

I don't see why Fourier transforms are even worth pointing out as an option, unless you just want to brag that you know what they are. If we're going to assume that we can take certain properties of arbitrarily selected waveforms and apply them to shield generators, why not simply suggest that they switch from AC to DC and then keep the shield on constantly, thus eliminating the frequency window except when they need to fire through it? Then they can just switch it off and on again. That's no more unreasonable than assuming they can superimpose waveforms.

Having said that, I think we should acknowledge that the whole "frequency window" thing was stupid anyway. If the shields were oscillating at a certain frequency, that doesn't mean incoming energy at any other frequency would be completely blocked; it just means that only part of it would get through. The difference between a perfectly tuned and phase-aligned attack and a completely untuned attack would not be as large as it appears in the show. Depending on the shape of the waveform, it might be more like a 60% difference, instead of taking a weapon up from "harmless" to "devastating". And no one ever explained how the enemy would be able to phase-align his weapon to the shields. If they can analyze the shield waveform from some kind of sensor or feedback in the weapon beam, they wouldn't need spies to acquire the shield frequency; they could just read it from their instruments.