## Electronics and Electrical Engineering Design Forum

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Thursday, December 28, 2017 by Len Murray

# Pulsed vs Unpulsed

Can someone please tell me - what is the difference between pulsed vs unpulsed waves?

I'm looking at buying a decent RF meter - probably Gigahertz Solutions - and noticed their high end meter had "A quantitative differentiation between pulsed and un-pulsed radiation".

I am not clear on the difference. Are all AC frequencies by definition pulsed? Or is there sort of a carrier wave that may have a steady unpulsed frequency, which then can be modulated, or pulsed by another frequency?

Is "natural" DC unpulsed?

Thank you.

• by  David Ashton (edited)

For data transmitted by radio you may see the terms ASK and FSK - Amplitude Shift Keying and Frequency Shift Keying.   ASK works by sending a pulse of Radio Frequency  (RF) for a "1" and then nothing for the same time for a "0".  FSK sends a constant RF signal but changes the frequency slightly for "1"s and "0"s.   So an ASK RF data signal would also be pulsed.

DC from a battery through a lamp would be unpulsed DC.  But all sorts of things use pulsed DC.  The old Teleprinters and Telex machines sent a 5- or 8-bit code of DC pulses - current for a "1",  no current for a "0".  The old RS232 serial interface sent pulses of either +12v or -12V to indicate 1s and 0s.  And the well known technique of Pulse Width Modulation (PWM) used to control LED brightness, motor torque, etc uses varying width pulses of DC rather than just varying the voltage - usually for reasons of efficiency.

So you can have pulsed or unpulsed sources of anything from DC to pretty much as far as you want to go - certainly into the Gigahertz region used by satellite TV, Radars  and cellphones. If the transmitter sends a signal for something and no signal for another thing, that's pulsed.  if it sends a constant signal, that's unpulsed.

I hope that makes it clearer but feel free to come back with more specifics.  Cheers // David

• Wow David - thanks so much for the thorough reply. I have a much better understanding. Still a couple questions, if you don't mind - and happy to take this off-line if preferred.

* Would it be accurate to say pulsed is analogous to intermittent frequency?

For some reason I seem to be stuck on the fact that there is an underlying "fundamental", steady, unpulsed frequency - and the pulsed are bursts of high amplitude, while the fundamental frequency remains constant...or something like that. After reading your post, I'm thinking this more accurately describes carrier signals.

Here's where I'm going with my questioning: I'm attempting to recreate pervasive EMF, specifically the wireless band of microwave. I'm doing experiments with water, and the impact  MW interactions have. I'm looking to transmit a broad range of frequencies - from around 800 MHz on up to near infrared.

I need to understand the proper equipment to purchase (signal generator, antenna, etc.) as well as how to best mimic current signals (pulsed, unpulsed, intensity, etc).

Thanks so much for any additional input.

Len -

• Len,

Your are right in thinking that there is a fundamental frequency that is constant but for the pulsed signal. the output is sometimes zero (or very close to zero). An example is a Morse code transmitter used in a ham radio station. The oscillator usually continues to oscillate even when it's not connected to the antenna.  From the outside, it looks like an intermittent output.

• Len,

Your are right in thinking that there is a fundamental frequency that is constant but for the pulsed signal. the output is sometimes zero (or very close to zero). An example is a Morse code transmitter used in a ham radio station. The oscillator usually continues to oscillate even when it's not connected to the antenna.  From the outside, it looks like an intermittent output.

• Thank you very much Elizabeth. Your (and other's) comments are very helpful, and saving me hours of research time - much appreciated. And on top of that, this is all beginning to make sense!
• by  David Ashton (edited)

Len - thanks.  I was going to give the example of a microwave oven.  The microwaves here are generated by a type of vacuum tube (valve) called a Magnetron.  These generate very high power (like 700 to 1000 watts or more) at radio frequencies in the 2.5 gigahertz range .  Magnetrons are the same thing they use for generating the very short pulse used in radars.  In home microwave ovens they are used in continuous mode, and to generate less power they are switched off for some of the time (for example on half power they might be on for 10 seconds, off for 10 seconds.  This is effectively pulse mode but with very long pulses!  But during the OFF time the magnetron has power removed completely and does not generate anything at all.  Basically pulsed mode means that POWER is not being generated during the OFF time of the pulses, only during the ON time.  It is the output POWER that is intermittent, not the frequency as such.   In Elizabeth's ham radio transmitter, you keep the oscillator running because it needs to be stable.  If you stop and start the oscillator it will usually put out varying frequency and amplitude during start up and that is NOT what you want from a radio transmitter.  So although the oscillator is continuous, the output is not - power is only supplied to the antenna when she presses her morse key.  So it is pulsed.  Morse is a type of Pulse Code Modulation (PCM) - the pulses are according to a code which enables the sending of information.  Modern digital telephone systems - and your CD player - do the same thing, just much much faster.

Re your comments on microwave interactions with water.  Very pure water is almost an insulator.  When it has other stuff dissolved it in it conducts better to varying degrees.  You could try this experiment:

Take a glass of distilled water.  Measure its resistance with a multimeter, keeping the metal of the probes fully underwater at opposite sides of the glass.  Also measure the water temperature.  Then put the glass in a microwave oven on full power for (say) 30 seconds.  Measure the temperature again and see how much it has gone up.

Then repeat the experiment with a teaspoon of salt added to the water.  Keep the start temperature the same if you can. you should find that (a) the resistance of the salt water is much less and (b) the salt water gets appreciably warmer for the same amount of microwave time.   (I haven't tried this so hope I am right!)

The salt makes the water conduct better and hence absorb the microwave energy better.

Your comments rang a bell so I checked and you have previously posted about this subject.   You seem to have the resources to purchase some nice test equipment (lucky man) but you do seem to be trying to run before you can walk theory-wise.  Can I suggest you get a couple of textbooks on communications and microwave theory, or maybe find some physical or online courses on these subjects?

Microwave test gear is not cheap and a variable frequency microwave generator is likely to be VERY expensive.  You can generate 10-50W of power at lower frequencies by buying second hand radio equipment on EBay - you'd get stuff in the 80 / 150 / 450 MHz ranges and maybe others.  But bear in mind a half-wave antenna is a few feet at 80 MHz and still around a foot at 450 MHz.  So you'd be looking at quite large containers of water to investigate at these frequencies.

A couple of respondents to your previous post - Adam Carlson in particular - highlighted the greater ease of  communicating through fresh water.  Same reasons as above.  The better the conductivity of something, the more RF energy it will absorb.  If you surround something in copper or aluminium - good conductors - no RF can get through.

I'd reiterate Rick Curl's warning on your previous post - TAKE GREAT CARE when playing with microwaves! Don't do anything like disable the safety lockout switch on your microwave oven.  That level of power could cause serious burns (not just skin deep either) in a few seconds.  Even a few hundred milliwatts can cause heating of your flesh.

Reply if you need more clarification on nay of the above.  But I'd agree with a previous response that this is a HUGE subject and not one that's easily covered in a forum like this.  Best // David

PS.  I found a nice article on water conductivity here, might be of interest....
• David -

Once again David, thank you for all the helpful information. What a new year's gift.

This explanation of mw pulses helps tremendously in my understanding. So bottom line - the "original" or base frequency remains the same, but the pulse is another thing. An original frequency of let's say 2.5 GHz remains; however, it could be unpulsed or pulsed. If pulsed, that can vary in duration, though when it is "on", the frequency is 2.5 GHz. Correct?

And yes, I understand the oscillator/morse code example. Thanks for that.

You are correct about me running before walking, I suppose. I have been doing some research here, and of course corresponding with folks like you. Definitely don't have unlimited resources - looking to get the right mix of DIY experimentation with a limited budget, attempting to attract funding.

Re what I'm trying to do with water - if you are interested - check out Gerald Pollack (univ. of WA). He discovered the "exclusion zone" in water. Without going into crazy detail here, he found when water interacts with UV, visible and IR light, water's composition changes from H2O to H3O2. It forms hexagon layers which exclude just about everything, and form a negative charge. The amorphous or bulk water it surrounds forms a positive charge. He calls this exclusion zone "EZ": a liquid crystal, the 4th phase of water.

I'm collaborating with him, first attempting to recreate this EZ layer for myself (which I have done), and next attempting to see the effects of microwave radiation.

Considering the average cell has over 2 quadrillion water molecules, and that the human body is comprised of around 99% water molecules (by number of molecules, not volume), this EZ behavior and its interaction with light is quite important. The generation of voltage - or lack of - is an important link to health.

I realize this is a huge topic, and the possible dangers involved. I appreciate the heads up. If you are so inclined, I'd be curious to hear any feedback once you understand more details of my experiments.

Thanks - Len

• Len...thanks, glad to be of help, and a happy new year to you.

Got a busy day but will look up GP later, sounds interesting stuff.

How do you detect the change from H20 to H3O2?

I wonder if this has anything to do with antibubbles, which I've always found fascinating?  I know they have a charge relative to the water that they form in.

Anyway Len I will read up on GP and reply again thereafter.

• There is lots of information on GP out there. Of particular value is his book, "The Fourth Phase of Water". But to get right to it, check out the 3:40 min mark of this video: https://www.youtube.com/watch?v=JnGCMQ8TJ_g

Water is contacting a hydrophilic surface, with a bunch of microspheres. In the presence of visible light, an exclusion zone (EZ) forms along the surface - H3O2, pushing all the amorphous water molecules along with the microspheres toward the center.

GP has placed a microelectrode in that EZ space, and another in the amorphous area, and has measured something like 200 mV...can't remember the exact value.

I've had pretty extensive discussions with Jerry - no mention of antibubbles..?

• Len I looked up  H3O2 on Google and there are widespread references to it as a scam, used for promoting "healthy" water, though a couple of sites do say that Gerard Pollock's work has been hijacked for this purpose (kind of like the legitimate work of Nikola Tesla being used to promote "Energy from nothing" scams).  Can you comment on this?

• Yes, there is no shortage of scammers out there, either disputing Jerry's work,  hijacking it, etc. He is disrupting some very fundamental long held concepts of biology and physics, which is bound to ruffle feathers. The simple water molecule is vastly more complex than what current science allows for, not to mention its interactions with external energy. He had a similar disruption factor with his earlier book, "Cells, Gels and the Engines of Life".

Re promoting "healthy" water, I would say if one is actually creating EZ water, than absolutely yes - it is healthy, if consumed right away. But that's the question - is EZ water being created? And even if it were, it has to be then bottled and shipped off to consumers. The EZ would degrade after time, and now you're just purchasing "no longer energized" water. On the other hand, if some device were purchased so a consumer could create EZ at home or something - I can't say, I'm not familiar with these devices. But I can say the only way to be sure it was creating true EZ water would be to measure it - microelectrodes and a multi-meter.

So yeah, I suppose its a natural outcome for a scammer, a relatively simple way to capitalize on something subjective. How is the uninformed consumer to know?

My main comment would be take it from the source. Keep poking around - the surface stuff you uncover may be more negative. As you dig deeper, check out some of the folks and organizations supporting him and his work. Pretty authentic and impressive.

If you do have any interest in this subject, I again would recommend checking out "The Fourth Phase of Water". Very informative, reads a bit like a novel...almost. A nice explanation without (in some cases) overly technical concepts, very compelling, methodical, convincing.