Delaying/shifting the start of a square wave inverter

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  • #1
CCatalyst
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TL;DR Summary
Or can a square wave function be phase-shifted at all?
I am trying to create a two phase type setup where I have a square wave in the multi-gigahertz frequency. However, I want the second wave to start once the first one reaches 90 degrees. How can the circuit be configured to do this? Will a phase shifter do or can a square wave be phase shifted at all even at this high frequency? And if now what do I need to do?
 

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  • #2
Baluncore
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And if now what do I need to do?
Will the frequency be fixed or variable?
What is the actual frequency range?
How square does it need to be, what bandwidth?
Maybe consider;
1. Lock a PLL to the input signal, using a quadrature phase detector, the VCO is then in quadrature to the input.
2. Can you start at twice the frequency then divide it by 4 with a pair of F/F, then generate square Sin and Cos waves.
3. Most microwave balanced mixer chips have a quadrature generator as part of the image rejection. Take a look at the techniques used, or use one of those chips, maybe in a PLL.
 
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  • #3
Tom.G
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If it is fixed frequency, just use a delay line; a length of wire, circuit board trace, or waveguide that is 1/4λ long.
 
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  • #4
berkeman
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Summary:: Or can a square wave function be phase-shifted at all?

I am trying to create a two phase type setup where I have a square wave in the multi-gigahertz frequency.
What experience do you have with "square waves" at multi GHz frequencies? What PCB simulation tool do you use? What lab equipment do you have for working at those frequencies?
 
  • #5
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Unless the inductance of the circuit is very low those "square waves" won't be very squared I think.
@CCatalyst I think the best answers can be given only when we know more about the device you are building
 
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  • #6
CCatalyst
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Will the frequency be fixed or variable?
What is the actual frequency range?
How square does it need to be, what bandwidth?
Well I'm not 100% sure what the frequency must be but it will be fixed during operation. Although I would like to try different configurations. I guess a sine wave wouldn't hurt either. It just looked extremely expensive or complicated to create a pure sine wave source so I figured that maybe a square wave would be the better option. However, if it does approximate something like a sine wave due to the high frequency I can live with it.
1. Lock a PLL to the input signal, using a quadrature phase detector, the VCO is then in quadrature to the input.
2. Can you start at twice the frequency then divide it by 4 with a pair of F/F, then generate square Sin and Cos waves.
3. Most microwave balanced mixer chips have a quadrature generator as part of the image rejection. Take a look at the techniques used, or use one of those chips, maybe in a PLL.
I am not familiar with any of those terms.
If it is fixed frequency, just use a delay line; a length of wire, circuit board trace, or waveguide that is 1/4λ long.
How long does the delay line have to be? Or how do I set up a circuit board trace? Or how does a waveguide create that sort of shift and do you have any idea how much waveguides cost?
What experience do you have with "square waves" at multi GHz frequencies? What PCB simulation tool do you use? What lab equipment do you have for working at those frequencies?
Unless the inductance of the circuit is very low those "square waves" won't be very squared I think.
@CCatalyst I think the best answers can be given only when we know more about the device you are building
If you are bot suggesting that square waves are nearly impossible at such a high frequency, the thought has crossed my mind from time to time. If that is the case it's not a big deal. If it looks more like a sine wave as a result, can I use conventional phase shifters? If that is the case that would make things easier for me.

As for what I am doing, it is related to this topic.
Remember THIS topic?
I was asking this in order to determine the precise nature of how iron affects electromagnetic signals so I can determine what the frequency should be.
 
  • #7
Baluncore
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I am not familiar with any of those terms.
Then you are not ready to design or build a microwave signal generator.

You do only need sinewaves for what you are doing.
Sweep generators with quadrature outputs are available.
You will have to buy one, or spend three years studying the subject.

The problem with iron and 1 GHz microwaves is that only a 1um skin on the surface of the iron will be involved in reflecting the energy. Multiple GHz will have an even thinner skin.
 
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  • #8
sophiecentaur
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Then you are not ready to design or build a microwave signal generator.
. . . or even specify what you want.
You do only need sinewaves for what you are doing.
It's unlikely to be a pure sine wave and it's also unlikely that the OP or the equipment would be aware of that.
For splitting, I'd suggest a 3dB directional coupler which produces good quadrature for the two (equal level) output signals. If the fourth port of the coupler is terminated well, each of the two output circuits are less affected by mis-termination in the other.

Without knowing what the "Multi" in multi Gigahertz frequency means then the details of a coupler would be hard to know. Has the OP ever dealt with microwave circuits before? A simulated design won't translate to a real experimental situation.
 
  • #9
Baluncore
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For splitting, I'd suggest a 3dB directional coupler which produces good quadrature for the two (equal level) output signals. If the fourth port of the coupler is terminated well, each of the two output circuits are less affected by mis-termination in the other.
That sounds like overkill for this project. I don't have such high hopes for a microwave powered induction motor that uses iron to make the magnetic field stronger.

Spinach now only has 10% of the iron it used to have listed on the ingredients, so that is out.
I am thinking that haemoglobin would not make such a good armature since the iron is isolated and alone which will not support the required induction of eddy currents.
On the other hand, hemocyanin from an octopus is based on two copper atoms, which should generate a stronger couple, but that might require an eight phase power divider.
https://www.minicircuits.com/appdoc/AN10-005.html
https://www.minicircuits.com/products/Splitters_tab3.html
 
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  • #10
sophiecentaur
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high hopes for a microwave powered induction motor
I'm thinking of a washing machine, powered by microwaves from an orbiting power satellite.
 
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  • #11
berkeman
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If you are bot suggesting that square waves are nearly impossible at such a high frequency, the thought has crossed my mind from time to time.
You think I'm a bot?
 
  • #13
Averagesupernova
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You think I'm a bot?
You've had us all fooled for a long time. How'd you do it so well?
 
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  • #14
sophiecentaur
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You've had us all fooled for a long time. How'd you do it so well?
He’s the original real random number generator from that other thread, perhaps.
 
  • #15
artis
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@berkeman said he recently got a "work trip" to China, I guess the bot needed some software upgrade and hardware tweaking...
Given it wasn't done remotely I'd speculate he is a high level bot, top security beware!

Someone alert Google's deepmind program and send a personal email to Noam Chomsky, I think Artificial General Intelligence is here already!


PS. Fun fact, Did you know that @berkeman actually has the backup version of this forums stored in his mind.
 
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  • #16
CCatalyst
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This is going WAY off topic. If a square wave circuit tuned to the microwave frequency instead makes what looks like something closer to a sine wave, then that's fine, in not preferred. The question is that can it be phase delayed by 90 degrees? And if an ordinary phase shifter will do all the better.

The problem with iron and 1 GHz microwaves is that only a 1um skin on the surface of the iron will be involved in reflecting the energy. Multiple GHz will have an even thinner skin.
But will it make the magnetic flux stronger? And what happens involving the rest of the iron then?
 
  • #17
Baluncore
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But will it make the magnetic flux stronger? And what happens involving the rest of the iron then?
The flux will only be stronger in the 1 um surface, which will be insignificant because the surface current will be limited by the very high surface resistance.

The rest of the iron plays no part in the game, it may as well not be there. Take a look behind a good mirror sometime, you will see very little light passing through.
 
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  • #18
berkeman
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This is going WAY off topic. If a square wave circuit tuned to the microwave frequency instead makes what looks like something closer to a sine wave, then that's fine, in not preferred. The question is that can it be phase delayed by 90 degrees? And if an ordinary phase shifter will do all the better.


But will it make the magnetic flux stronger? And what happens involving the rest of the iron then?
No, we are trying to figure out if we can help you or if you are a fantisizing troll. What GHz circuits have you successfully designed and built so far? Please share your schematics and test data, or this thread will be closed as another waste of time.
 
  • #19
CCatalyst
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No, we are trying to figure out if we can help you or if you are a fantisizing troll. What GHz circuits have you successfully designed and built so far? Please share your schematics and test data, or this thread will be closed as another waste of time.
Sorry of accusing you of being a bot. I meant to say "not". (B and N are right next to each other on the keyboard.)

The reason why I am asking this is because I legitimately don't know. Before I have some sort of design ready I need to have some questions answered first. For example, if a square wave generator working at a Multi-Ghz frequency ends up creating what looks like a sine wave, can an ordinary phase shifter be used? If not it looks like a quadrature generator is my best option. I will let you know more soon.
 
  • #20
artis
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Listen @CCatalyst first of all we just had some laugh , no worries everyone knows you simply made a typing error. And @berkeman didn't put a "smiley" emoji under my last joke here (emphasis on a specific action very much added... :D) so even among us there is no 100% agreement about what we are really laughing about... :biggrin:

Let me try to help you out here, @Baluncore is a sophisticated guy , he tends to give complex answers let me try to give a more simple one.
Your confusion about iron making B fields stronger is simple. Whenever you have some forms of current whether through a coil or even along a straight wire you have a B field set up.
Fields (including B) can travel through different mediums but there is a catch, different mediums attenuate (change/lessen) fields differently. It just so happens to be that for DC and low frequencies iron due to it's atomic structure can help "guide" a B field better than air.
So if one uses a core that is not air but metal one can have the same field strength with less effort, less current and/or turns. Sure other factors start playing a role like core material properties and the need for laminations in AC but that is another level of knowledge I suggest you read about.

Now talking about your Ghz frequencies which is way up there in the mm wave spectrum of microwaves there really aren't that many materials that can support a B field that changes so fast without introducing a lot of loss , energy wasted as heat in the core. + as @Baluncore mentioned already there is a thing called skin effect so your effective core area will be just that of a thin layer on surface.
For this frequency range ferrites are used. Different ferrites are used for anything from Khz up to Mhz and some rare types even up to 20 and maybe even more Ghz. Or in other places no core at all is used, simply air, because air doesn't introduce any such losses as cores do at this high frequency, only drawback you need more current to have the same field strength.

Next you need to read about inductance, it's a "thing" that every conducting piece of wire has.
For a given frequency the more inductance the less "square wavy" your signal will be , at Ghz frequencies , even a few turns of wire could be the difference between a somewhat square like signal and a sine wave.
If you are ok with sine then no worries, because sine is probably everything you will get without some extra sophisticated hardware and implementation.
Now this being said yes you can phase shift one signal relative to another, because BOT (missing H, yes pun very much intended) are just signals and signals can be attenuated in different ways , they can be even overlapped and summed etc.
 
  • #21
CCatalyst
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Thank you for the understanding. Just don't let berkeman lock this topic.

As for what I am trying to do is similar to a Chinese patent somewhere. Except this person does not use iron and I do not know why. Plus the geometry I am trying to use is totally different. I will tell you more later.
 
  • #22
berkeman
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Sorry of accusing you of being a bot. I meant to say "not". (B and N are right next to each other on the keyboard.)
Ah, I was hoping it was a typo. I wasn't able to parse your sentence even with single letter correction attempts, though. I haven't been a bot since the year 2000.

Just don't let berkeman lock this topic.
:devil:

Maybe consider;
1. Lock a PLL to the input signal, using a quadrature phase detector, the VCO is then in quadrature to the input.
2. Can you start at twice the frequency then divide it by 4 with a pair of F/F, then generate square Sin and Cos waves.
@CCatalyst -- This is the usual way that we create quadrature timing signals. It is done often in communication waveform processing, since you will have I (in-phase) and Q (quadrature phase) components in the communication signals.

Your cavalier mention of GHz frequencies (and "square waves" at those frequencies) has several problems:
  • It takes very specialized design skills and years of experience to effectively design circuits to operate in the GHz region (I have some of those skills, but I am honest enough to hire specialized consultants to help me with such designs, the most recent being at 2.4GHz)
  • It takes many hundreds of thousands of dollars to put together the equipment to test circuits operating in the GHz region (my lab has all of that equipment)
  • In any RF project (but especially in the GHz region, and if you are intending to use much power), you need to understand the issue of EMI and be very careful that your experimental circuits and final product design do not interfere with any other RF devices. You absolutely do not want to be experimenting in your garage and throwing out all kinds of EMI noise into the neighborhood, cutting out emergency system radio traffic or other radio traffic. Somebody like me will be knocking on your door very soon after you start causing that kind of interference...
 
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  • #23
artis
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Somebody like me will be knocking on your door very soon after you start causing that kind of interference...
That is if he leaves the interference on for long enough, but maybe he just pulses the thing and you are left forever guessing unless one sets up a "listening" station in realtime (multiple ones I guess) and triangulate?
 
  • #24
berkeman
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That is if he leaves the interference on for long enough, but maybe he just pulses the thing and you are left forever guessing unless one sets up a "listening" station in realtime (multiple ones I guess) and triangulate?
You don't need to triangulate when you are mobile. We practice this stuff all the time, and we've been called out for actual field problems in the past. Don't mess with the spectrum! :smile:

1631463404654.png

https://tamiamiarc.org/what-is-a-fox-hunt/
 
  • #25
artis
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@berkeman so hunting for interference source is somewhat like metal detecting , you just turn your antenna towards the point of highest signal and then approach that direction again for strongest signal right?
Unlike metal detecting though in air the signal could potentially bounce around and lead you astray could it ?
 
  • #26
berkeman
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Multipath reflections can definitely cause some confusion during DF or "fox hunting".

The more experienced hunters use phased array antennas mounted on their vehicles to speed up the chase. Very impressive.
 
  • #27
Baluncore
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Thank you for the understanding. Just don't let berkeman lock this topic.

As for what I am trying to do is similar to a Chinese patent somewhere. Except this person does not use iron and I do not know why. Plus the geometry I am trying to use is totally different. I will tell you more later.
I cannot see how CCatalyst can benefit from a thread in a 'language' and field he does not understand. Nothing will come of it, so the thread might as well be closed.

The fact that the unspecified application is a secret indicates that he will almost certainly not succeed. As a typical deluded inventor, CCatalyst needs to dream. Who are we to stop someone dreaming. So long as he dreams, nothing will happen. Any experienced Federal Radio Inspector will tell you the same, so I don't think anyone needs to worry.

Unlike metal detecting though in air the signal could potentially bounce around and lead you astray could it ?
Tracking down illegal transmitters and sources of EMI is a black art that comes naturally to very few people. It is not an art that can be taught to just anyone. A good tracker is not distracted by reflections, they use any reflections as additional information to locate the source faster. Like a good hound on the trail of a fox, they go more or less straight up to their quarry, without back-tracking nor hesitation.
 
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  • #28
CCatalyst
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I cannot see how CCatalyst can benefit from a thread in a 'language' and field he does not understand.
That's not completely true. I took a semester of circuits.

But I am changing my design. I am no longer going to use iron-based solenoids. Now I am going to capacitors instead. So now I need information about how quickly the ELECTRIC FIELD propagates thorough materials, including insulators and conductors. Still, the inputs are the same, a (possibly) square wave that has two outputs, one the default phase and the second phase shifted 90 degrees. Both signals simply go to both ends of the capacitor. I want to know how quickly the electric field propagates through various materials so that I know what the dimensions of the capacitor should be.

But you do bring up a valid concern, EMI interference with other electronics. But aren't there ways to block it though? Such as placing the device in an iron box? That's what they do with microwave ovens.

And finally it doesn't HAVE to be a perfect square wave. It can resemble a sine wave and I would be just fine, but if it does look like a sine wave, will a conventional resistance-capacitance phase shifter work?

Update:
  • It takes very specialized design skills and years of experience to effectively design circuits to operate in the GHz region (I have some of those skills, but I am honest enough to hire specialized consultants to help me with such designs, the most recent being at 2.4GHz)
  • It takes many hundreds of thousands of dollars to put together the equipment to test circuits operating in the GHz region (my lab has all of that equipment)
  • In any RF project (but especially in the GHz region, and if you are intending to use much power), you need to understand the issue of EMI and be very careful that your experimental circuits and final product design do not interfere with any other RF devices. You absolutely do not want to be experimenting in your garage and throwing out all kinds of EMI noise into the neighborhood, cutting out emergency system radio traffic or other radio traffic. Somebody like me will be knocking on your door very soon after you start causing that kind of interference...
Maybe you're right in that regard. Do you know of any good microwave generators/mixers that I can buy prefabricated that won't break the bank? But with my design change hopefully I will not need much power. If I needed too much power it would defeat the purpose.
 
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  • #29
Baluncore
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And finally it doesn't HAVE to be a perfect square wave. It can resemble a sine wave and I would be just fine, but if it does look like a sine wave, will a conventional resistance-capacitance phase shifter work?
I don't think you have any choice. Any wave at 1 GHz that is distorted will have harmonics at 2 GHz, 3 GHz and so on … You may as well only consider the fundamental as the harmonics are a long way from the frequency you are generating, so they will be strongly attenuated by the quadrature phase shifter.

You will not survive in microwaves if you do not understand Fourier Analysis and transmission line circuit techniques. I'm afraid you are still so far behind that you think you are first.
 
  • #30
artis
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@CCatalyst it is good that you won't use iron base solenoids because truth be told you should not have even considered them in the first place. Iron based solenoids really don't work for RF frequencies. They are made for DC and typical low frequency AC.
 
  • #31
CCatalyst
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I am almost there. I just need a frequency generator or inverter of some sort, with a frequency of no lower than 4GHz, hopefully one that won't break the bank either.

If it is fixed frequency, just use a delay line; a length of wire, circuit board trace, or waveguide that is 1/4λ long.
As for a phase shifter, I will use the delay line method, thanks.
 
  • #32
TonyStewartEE75
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Summary:: Or can a square wave function be phase-shifted at all?

I am trying to create a two phase type setup where I have a square wave in the multi-gigahertz frequency. However, I want the second wave to start once the first one reaches 90 degrees. How can the circuit be configured to do this? Will a phase shifter do or can a square wave be phase shifted at all even at this high frequency? And if now what do I need to do?
You cannot create a square wave at microwave frequencies.

It is not possible.

But you can make quadrature sine waves with some harmonics. You are not able to control the phase and amplitude of those harmonics found in a square wave due to the geometric sensitivity of standing waves and loss tangents of dielectric.

try making it at 100 MHz with over 10 harmonics after you get 1kHz quadrature to work.
 
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  • #33
CCatalyst
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You cannot create a square wave at microwave frequencies.

It is not possible.

But you can make quadrature sine waves with some harmonics. You are not able to control the phase and amplitude of those harmonics found in a square wave due to the geometric sensitivity of standing waves and loss tangents of dielectric.

try making it at 100 MHz with over 10 harmonics after you get 1kHz quadrature to work.
It no longer has to be a square wave.
 
  • #34
sophiecentaur
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As for a phase shifter, I will use the delay line method, thanks.
I understand that you find the idea of a length of delay line attractive; it sounds straightforward. However, you would need a circuit analyser to adjust for quadrature phase. Using a directional coupler gives you 'good' quadrature over a wide frequency range. I don't know what sort of hardware you envisage but, at a few GHz, it's really not trivial, unless you are already fairly expert in the field. You need to plan the circuit systems very early on. If you plan to use printed circuit techniques (micro strip) then couplers are easy to achieve (DIY) - much more so than getting the right line lengths. All you have to do is keep the lengths equal - coax or whatever.
 
  • #35
CCatalyst
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I understand that you find the idea of a length of delay line attractive; it sounds straightforward. However, you would need a circuit analyser to adjust for quadrature phase. Using a directional coupler gives you 'good' quadrature over a wide frequency range. I don't know what sort of hardware you envisage but, at a few GHz, it's really not trivial, unless you are already fairly expert in the field. You need to plan the circuit systems very early on. If you plan to use printed circuit techniques (micro strip) then couplers are easy to achieve (DIY) - much more so than getting the right line lengths. All you have to do is keep the lengths equal - coax or whatever.
Well what do you recommend? The delay wire or the quadrature method? Also I am going to use the 1.575GHz patch-type antenna for this. I am going to use them instead of inductors because not only will iron cores not work for such high frequencies (reasons why were discussed earlier) but it would just not be powerful enough. I need both a small enough right and left hand polarization antenna that does this.

By the way, how do I POWER RF systems? Is there anything that con hold a battery and use it to run an RF system? And is it adjustable?

Oh, and to those now joining, I NO LONGER need a square wave for this.
 

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