Former Illuminatist reveals Illuminati?
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Interesting stuff. Wasn't too sure about the shape shifting videos until I came across this one. Now I'm like WTF
[FLASH]http://www.youtube.com/v/BugI_6Q7sCM&hl=en&fs=1[/FLASH]
[FLASH]http://www.youtube.com/v/BugI_6Q7sCM&hl=en&fs=1[/FLASH]
Interesting stuff. Wasn't too sure about the shape shifting videos until I came across this one. Now I'm like WTF
[FLASH]http://www.youtube.com/v/BugI_6Q7sCM&hl=en&fs=1[/FLASH]
Props to Roster for starting this thread. Those videos are extremely informative.
Thanks. To be honest I did not know the thread would become this informative and entertaining with all these posts. I really thought most on bgol(for a porn board this place sure gets the most varied topics possible posted
) saw or heard of this and I just wanted feedback on what I saw in terms of credibility.
And you see Fish People and Snake People in the forest. GTFOH!!
You better chill before he thinks your a reptile. You almost had me Captain...These reptiles that you cant see or hear(Yet somehow know to be reptiles) can...get this...turn invisible teleport and shapeshift, have technology that surpasses anything we have but still have to hide. You surveilled these creatures for years...yet you never seen this shit, yet you know it exists...and they feed on fear and anger, but youve never seen them feed or seen anything but you surveilled them for years, but in actuality you werent surveilling anything because you didnt see shit actually
I have a headache.
Without the special effects.Interesting stuff. Wasn't too sure about the shape shifting videos until I came across this one. Now I'm like WTF
[FLASH]http://www.youtube.com/v/BugI_6Q7sCM&hl=en&fs=1[/FLASH]
[FLASH]http://www.youtube.com/v/kRUmId2Gyto&hl=en&fs=1[/FLASH]
Watch closely, she's one of them too. Albeit a dumb one!
[FLASH]http://www.youtube.com/v/nokTjEdaUGg&hl=en&fs=1[/FLASH]
Man...I'm scared to go to bed.
the feathered serpent dragon kaeyzar sose is gon' get yaYou better chill before he thinks your a reptile. You almost had me Captain...These reptiles that you cant see or hear(Yet somehow know to be reptiles) can...get this...turn invisible teleport and shapeshift, have technology that surpasses anything we have but still have to hide. You surveilled these creatures for years...yet you never seen this shit, yet you know it exists...and they feed on fear and anger, but youve never seen them feed or seen anything but you surveilled them for years, but in actuality you werent surveilling anything because you didnt see shit actually
I have a headache.
Believing is a choice!
Show me & everyone where I said I know them to be reptiles.
When did I say I haven't seen them feed?
Nice try,
whether they believe it or not, the people on BGOL are intelligent enough to understand what I wrote. Your attempt here to misquote what I have written leaves a lot of questions. Maybe your comprehension is a little off right now. I'll accept that. 
Like I said before and you can quote this "They are not more intelligent than humans"
It is you who keeps stating that these creatures are more intelligent than humans. Why? My friends and I refer to them as galactic retards!
I've never believed or ever will believe that they were more intelligent than humans. I know that humanity will defeat them.The ones I've encountered are actually mentally slower in processing things and they lack creativity like humans. They have more of a hive mentality, like drones, or worker ants. This all implys that they are controlled by a superior. Slick and deceptive by all means but not intelligent, there is a difference.
They are banking on the fact that people are not paying attention to what happens around them. That's pretty bold of them, and foolish. That only works for so long, then they have to create mass distractions. I encourage people to prepare themselves and gather their own information about these entities. Humans WILL defeat them!
I will not go back and forward with you on this. I will continue to educate people, WITHOUT FEAR!
And you see Fish People and Snake People in the forest. GTFOH!!
Isn't that Anubis in your avatar?
Health is also important. Be sure to research the herbs that purify and cleanses the blood. This is very important!
Study those frequencies. Check out this sister by the name of Dr. Mona Harrison, I remember you said something about water. My friends can program water to repel these suckers also. On the link below you can listen to her lectures. Dr. Mona Harrison, M.D.
http://www.realtime.net/anr/herbs.html
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i can't get a response to my last brotha?Health is also important. Be sure to research the herbs that purify and cleanses the blood. This is very important!
Dr. Mona Harrison, M.D.
http://www.realtime.net/anr/herbs.html
Much respect but I can't do that. Remember I said DISCIPLINE was the key. It won't make you popular but it will keep you ahead of these things. Here are some basic rules we go by. Explainations in red.
Rule #1 Know yourself and your abilities. Believe in yourself and your abilities. Know the enemy and believe in its abilities. Know that you are in a war. This all goes back to the most ancient military stategy on record.
Rule #2 Never beileve anything from someone 100%. The entities have a lot of disinformation out there. Even people WE trust may have been misinformed. DECEPTION is their specialty.
Rule #3 Never send out compelling evidence over the wire. This means net, phone, or mail. It allows them to much opportunity to intercept, counter and spread their disinformation.
Rule #4 Never congregate in large groups. Unless you are advanced in protection techniques. A lot of which I posted here. They have a lot of spies/eyes. If we give out direct ways of doing things they may learn what they may not be aware of.
Rule #5 Never discuss anything with someone you don't know in an unprotected area. Again, they have spies and are always watching humans. But they have limitations that can be exploited.
Rule #6 Never get emotional about things that are presented to the masses. Politics,social issues, etc.,no matter how bad it is.
Rule #7 Avoid public confrontations with ANYONE. Don't be a wuss, but be smart. There is no room for fear.
Rule #8 Never drink water from an open container from strangers. Research water and you will understand.
Rule #9 Never let anyone know your desires, the #1 human weakness. Contain and control your desires, it takes DISCIPLINE.
Rule #10 Avoid negative people and instigators. A common tactic of theirs is to fill an area with negative thoughts, then they can feed. It passes like a virus. Reject that type of thinking when some else brings it to you. Be mindful of your own thoughts.
Rule #11 Meditate on the previous ten rules. Feel free to add yourself some rules based on your personal views and aquired knowledge.
Much respect but I can't do that. Remember I said DISCIPLINE was the key. It won't make you popular but it will keep you ahead of these things. Here are some basic rules we go by. Explainations in red.
Rule #1 Know yourself and your abilities. Believe in yourself and your abilities. Know the enemy and believe in its abilities. Know that you are in a war. This all goes back to the most ancient military stategy on record.
Rule #2 Never beileve anything from someone 100%. The entities have a lot of disinformation out there. Even people WE trust may have been misinformed. DECEPTION is their specialty.
Rule #3 Never send out compelling evidence over the wire. This means net, phone, or mail. It allows them to much opportunity to intercept, counter and spread their disinformation.
Rule #4 Never congregate in large groups. Unless you are advanced in protection techniques. A lot of which I posted here. They have a lot of spies/eyes. If we give out direct ways of doing things they may learn what they may not be aware of.
Rule #5 Never discuss anything with someone you don't know in an unprotected area. Again, they have spies and are always watching humans. But they have limitations that can be exploited.
Rule #6 Never get emotional about things that are presented to the masses. Politics,social issues, etc.,no matter how bad it is.
Rule #7 Avoid public confrontations with ANYONE. Don't be a wuss, but be smart. There is no room for fear.
Rule #8 Never drink water from an open container from strangers. Research water and you will understand.
Rule #9 Never let anyone know your desires, the #1 human weakness. Contain and control your desires, it takes DISCIPLINE.
Rule #10 Avoid negative people and instigators. A common tactic of theirs is to fill an area with negative thoughts, then they can feed. It passes like a virus. Reject that type of thinking when some else brings it to you. Be mindful of your own thoughts.
Rule #11 Meditate on the previous ten rules. Feel free to add yourself some rules based on your personal views and aquired knowledge.
Health is also important. Be sure to research the herbs that purify and cleanses the blood. This is very important!
Dr. Mona Harrison, M.D.
http://www.realtime.net/anr/herbs.html
I was talking about turnin a cup of water into a harddrive but a scientist u posted beat me to it
I was just thinkin about tryin some sort of cleanse or somethin, gonna check her link out now
really appreciate all this capt + mike....
I was talking about turnin a cup of water into a harddrive but a scientist u posted beat me to it
I was just thinkin about tryin some sort of cleanse or somethin, gonna check her link out now
Now, now,
DNA IS CREATED BY A WAVE (aka frequency)
Not only does this field create all the physical matter we now see around us, it is the very root from which life itself springs, already built to order. It is the chicken AND the egg.
The DNA molecule is a visible, measurable, ‘solid’ form of the waves that constantly ripple through this energy field — throughout the entire Universe. These waves, loaded with information, surround you right now as you read these words — just like radio, satellite TV and cell-phone signals.
When water runs down the side of a mountain, it captures all the loose rocks and rolls them into the bottom of a stream. Similarly, the waves in the Field gather up whatever atoms and molecules they find in a given area — on any planet in the Universe where the right conditions exist, such as liquid water — and immediately push and nudge those little pieces into forming DNA molecules.
The structure of DNA is obviously a lot more complicated than the rocks at the bottom of a stream, but the principle is the same. We can prove scientifically that the Field is doing this. These subtle pressures have been measured and studied in a laboratory.
Little living critters have already been generated spontaneously, in an utterly sterilized environment, from nothing more than distilled water, simple molecules and a little zap of electricity to excite the waves in the Field. All this growth occurs in perfectly sealed environments that had been super-heated to white-hot levels, where no living thing could possibly have survived — at least not within any conventional scientific models.
DNA DO-SI-DO
The waves in this field not only create DNA by gathering molecules together — they can also re-arrange a DNA molecule.
Russian scientists have already proven that plants, animals and amphibians can be completely re-arranged into other species — particularly if you catch them in embryonic form. This has nothing to do with cloning or gene splicing. All they do is zap the DNA in the embryo with a beam of light. The light beam carries the ‘wave’ of another organism in it.
In one example we will present, a frog embryo was completely re-arranged, with nothing more than a beam of light, into a salamander. The salamander grew to full adulthood and showed no signs of ever having started as a frog. When it had babies they were salamanders, not frogs. Our little friend never got sick or died prematurely like normal clones would.
How could a solid, real DNA molecule shift around enough to create the codes to build an entirely different body?
Here’s the key: DNA is not a fixed, hard structure. There are indeed many small ‘pieces’ that can break off from one part of a DNA molecule and move around to another part. Scientists call these little pieces ‘retrotransposons.’ When they move around, the code changes.
If you ‘energize’ a creature like a salamander with a beam of light (or other forms of energy), and then re-direct the beam into the embryo of a frog, the ‘wave’ will re-arrange the frog’s DNA to create a salamander.
The little ‘retrotransposons’ in the frog’s DNA move themselves around to fit the new wave from the salamander. This is similar to how rocks will gather in a new area if the stream of water shifts on its way down the mountainside.
This mechanism drives life to evolve on Earth spontaneously, in very short periods of time. All the clues to explain this process already exist in the fossil record and in groundbreaking Russian laboratory experiments with DNA.
Darwin was wrong.
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Damn CAPTAIN, deep as usual. I wish I could zap these humanoids with a beam of light and turn them from the creatures they are into rational thinking humans.
I wish I could zap these humanoids with a beam of light and turn them from the creatures they are into rational thinking humans.Damn CAPTAIN, deep as usual.
Hey G.
You stayed clear of this thread for a while. What you propose is highly probable but infringes on certain rights. Besides, that what you speak of is already a process of what you speak....got me.Apparently!
You know it is amazing how people rarely notice the links between ancient and modern technologies. Look at where a lot of their inspirations may have come from. These are some passaqes from "The Complete Pyramid Source Book" by John DeSalvo, Ph.D., another tell-almost-all, that any scientist, engineer, or anyone interested or working with technology should read.SOME PYRAMID HISTORY
Many tourists have climbed to the top of the Great Pyramid. One
such person was Sir Siemen’s, a British inventor who climbed to the top with his Arab guides during the end of the 19th century. One of his guides called attention to the fact that when he raised his hand with fingers spread apart, he would hear a ringing noise. Siemen raised his index finger and felt a prickling sensation. He also received an electric shock when he tried to drink from a bottle of wine. Being a scientist, Siemen then moistened a newspaper and wrapped it around the wine bottle to convert it into a Leyden jar (an early form of a capacitor). When he held it above his head, it became charged with electricity. Sparks were then emitted from the bottle. One of the Arab guides got frightened and thought Siemen was up to some witchcraft and attempted to seize Siemen’s companion. When Siemen’s noticed this, he pointed the bottle towards the Arab and gave him such a shock that it knocked the Arab to the ground almost rendering him unconscious.
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ADVANCED PRECISION
Christopher Dunn, one of our Research Directors, has said the
following about the casing stones in his book “The Giza Power
Plant”. The records show that the outer casing blocks were square and flat, with a mean variation of 1/100 inch over an area of thirty-five square feet. Fitted together, the blocks maintained a gap of 0 to 1/50 inch, which might be compared with the thickness of a fingernail. Inside this gap was cement that bonded the limestone so firmly that the strength of the joint was greater than the limestone itself. Here was a prehistoric monument that was constructed with such precision that you could not find a comparable modern building.More remarkable to me was that the builders eventually found it necessary to maintain
a standard of precision that can be found today in machine shops, but certainly not on building sites.
Originally, the pyramid was completely covered with smooth, highly polished limestone blocks known as casing stones. These stones came from the quarries of Tura and Masara in the Moqattam Hills on the opposite side of the Nile. These casing stones reflected the sun’s light and made the pyramid shine like a jewel. The ancient Egyptians called the Great Pyramid “Ikhet”, meaning the “Glorious Light”. At the present, only a few of these are left in position on each side at the base.
The Arabs stripped off most of them in the 14th century after an earthquake loosened many. They cut them up to build mosques and buildings in Cairo. One of the largest remaining casing stones is nearly 5 feet high by 8 feet and weighs about 15 tons. How these blocks were transported and assembled remains a mystery. To manufacture just two blocks with a tolerance of .010 inch and place them together with a gap of no more than .020 inch is a remarkable feat. The Great Pyramid had at one time over 100,000 similar casing stones.
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Herodotus, the Greek historian of the fifth century BC, regarded as the father of history wrote the earliest description in existence of the pyramids. When Herodotus visited the pyramids in 440 B.C., it was as old to him as his period is to us. He wrote that each of the pyramid’s four faces were still covered with highly polished limestone (casingstone). Also the joints were so fine that they could hardly be seen. The ancient writer Strabo said “It seemed like a building let down from heaven, untouched by human hands.” It has been calculated that the original pyramid with its casing stones would act like gigantic mirrors and reflect light so powerful that it would be visible from the moon as a shining star on earth.
thats a fantastic pyramid drop - props - theres a thread am preparing - it would contain some esoteric pyramid info like the house of the serpent etc... its a part III finale to the Anti-C. posts - I look forward to your response when the thread opens
OOPS! Here's the download link for that book.
http://rapidshare.com/files/119197537/John_DeSalvo_-_The_Complete_Pyramid_Sourcebook.rar
Other resources
http://rapidshare.com/files/101335326/Occult_MedicineSpunkins.rar
http://rapidshare.com/files/107573408/vol3SpunkinsUpmagic.rar
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Cap i wanna try some of them pyramid experiments but i dont have a room that i can use, they all have something that may interfere. What do u suggest may help?
an i aint stressin that water thing, i know no idea is new, just rediscovered
Oh and that stuff on dna/rna is brand new to me but alot of stuff i've been reading about matter and energy has been leading to those conclusions though.So what part does the epigenome play in this?
an i aint stressin that water thing, i know no idea is new, just rediscovered
Oh and that stuff on dna/rna is brand new to me but alot of stuff i've been reading about matter and energy has been leading to those conclusions though.So what part does the epigenome play in this?
good lookin' outOOPS! Here's the download link for that book.
http://rapidshare.com/files/119197537/John_DeSalvo_-_The_Complete_Pyramid_Sourcebook.rar
Other resources
http://rapidshare.com/files/101335326/Occult_MedicineSpunkins.rar
http://rapidshare.com/files/107573408/vol3SpunkinsUpmagic.rar
Cap i wanna try some of them pyramid experiments but i dont have a room that i can use, they all have something that may interfere. What do u suggest may help?
an i aint stressin that water thing, i know no idea is new, just rediscovered
Oh and that stuff on dna/rna is brand new to me but alot of stuff i've been reading about matter and energy has been leading to those conclusions though.So what part does the epigenome play in this?
What type of interference? You can build the small ones, with 6 inch bases for those experiments. If you are looking to work on yourself you can build the one with 24 a inch base and mount it onto a chair. By-the-way, how did your hydrogen generator go? Maybe I'll post some pics of the ones I did.
Epigenomes ,seems to be the mechanisms actually recieving and distributing the frequencies relative to the overall genetic similarities through generations. Heredity coding of an organism, also known as gene expression. I believe this is more related to the RNA role. If you study he DNA/RNA you may find that there seems to be some mathematical computation to the human physical structures. This is what has led a lot of modern people to believe that we exist in some kind of computer, Matrix. Although this was implied by the Egyptians long ago.
If this reality is in our minds then the power to alter it is also in our minds.Again, be careful, because we've encountered these suspects working in various government labs, science labs, especially in the field of genetics. They seem to be trying to watch/learn something or everything. A lot of information released to the public is usually a distortion of or half of the facts. It seems to be a process of hindering or slowing the advancement of science.
Go figure.
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Electrical fields that my electronics create. I dont think it'll be enough to just unplug the tv and the laptop and i dont see myself moving a radiator either
. It wont be a problem for the first experiments i do since it'll just be strawberries and small plants in the closet but that setup wont work for tryin it on meRight under the chair? If so that my have helped me decide how i was gonna try the pyramid on myself
You talking about the joe cell? That things supposed to capture and store orgone but the intructions on how to build one are very specific. For example u cant use tools that would heat the metal when cutting parts for the cell
But f you're talkin about the using of water as a harddrive thing then I'm a long ways from building that. Even if somebody has done it already i wanna still make it from the ground up
Epigenomes ,seems to be the mechanisms actually recieving and distributing the frequencies relative to the overall genetic similarities through generations. Heredity coding of an organism, also known as gene expression. I believe this is more related to the RNA role. If you study he DNA/RNA you may find that there seems to be some mathematical computation to the human physical structures. This is what has led a lot of modern people to believe that we exist in some kind of computer, Matrix. Although this was implied by the Egyptians long ago.
this is what i figured. It protects and stores the DNA as well as process signals with instructions on what parts of the genome to expose to RNA for replication. Similiar to how the cell wall is supposed to protect the organelles within cell as well as receive electrical/chemical signals from nearby cells or neural cells
Again, be careful, because we've encountered these suspects working in various government labs, science labs, especially in the field of genetics. They seem to be trying to watch/learn something or everything. A lot of information released to the public is usually a distortion of or half of the facts. It seems to be a process of hindering or slowing the advancement of science.
Alot of the misinformation spreaders tend to stand out like sore thumbs but a few always sneak thru so i'll keep my eye open
Be careful, your thoughts may not be your own. FOR THE NON-BELIEVERS. THIS IS A DEVICE THAT CAN SPEAK INTO A PERSON'S BRAIN.
United States Patent 6,587,729
O'Loughlin , et al. July 1, 2003
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Apparatus for audibly communicating speech using the radio frequency hearing effect
Abstract
A modulation process with a fully suppressed carrier and input preprocessor filtering to produce an encoded output; for amplitude modulation (AM) and audio speech preprocessor filtering, intelligible subjective sound is produced when the encoded signal is demodulated using the RF Hearing Effect. Suitable forms of carrier suppressed modulation include single sideband (SSB) and carrier suppressed amplitude modulation (CSAM), with both sidebands present.
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Inventors: O'Loughlin; James P. (Placitas, NM); Loree; Diana L. (Albuquerque, NM)
Assignee: The United States of America as represented by the Secretary of the Air (Washington, DC)
Appl. No.: 131626
Filed: April 24, 2002
Current U.S. Class: 607/55; 128/897; 332/167; 381/151; 600/586
Intern'l Class: H03C 001/54
Field of Search: 332/167 381/151 607/56,55 340/384.1 600/559,23,586 128/897,898
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References Cited [Referenced By]
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U.S. Patent Documents
3563246 Feb., 1971 Puharich et al. 607/55.
3629521 Dec., 1971 Puharich et al. 607/56.
4835791 May., 1989 Daoud 375/301.
5450044 Sep., 1995 Hulick 332/103.
Primary Examiner: Schaetzle; Kennedy
Attorney, Agent or Firm: Skorich; James M.
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Goverment Interests
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The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment of any royalty thereon.
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Parent Case Text
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This application is a division of U.S. patent application Ser. No. 08/766,687 filed on Dec. 13, 1996, now U.S. Pat. No. 6,470,214, and claims the benefit of the foregoing filing date.
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Claims
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What is claimed is:
1. An apparatus for communicating an audio signal a(t), comprising:
an audio predistortion filter having a filter function As(f) for producing a first output signal a(t)As(t) from the audio signal a(t);
means for adding a bias A to the first output signal, to produce a second output signal a(t)As(f)+A;
a square root processor for producing a third output signal (a(t)As(f)+A).sup.1/2 responsive to the second output signal; and
a modulator for producing a double sideband output signal responsive to the third output signal, having a carrier frequency of .omega..sub.c, and being mathematically described by (a(t)As(f)+A).sup.1/2 sin(.omega..sub.c t); and
transmitting the double sideband output signal to a demodulator, whereby the audio signal a(t) is recovered from the double sideband output signal.
2. The communication apparatus defined in claim 1 wherein:
the double sideband output signal has RF power; and
the demodulator is for converting the RF power into acoustic pressure waves.
3. The communication apparatus defined in claim 2 wherein:
the demodulator converts the RF power into the acoustic pressure waves by means of thermal expansion and contraction, whereby
the acoustic pressure waves approximate the audio signal a(t).
4. The communication apparatus defined in claim 2 wherein the demodulator includes a mass that expands and contracts responsive to the RE power of the double sideband output signal.
5. The communication apparatus defined in claim 4 wherein the mass is approximately spherical.
6. The communication apparatus defined in claim 1 wherein:
the double sideband output signal is comprised of a first sideband component and a second sideband component; and
means for suppressing the second sideband component, whereby
the demodulator recovers the audio signal a(t) solely from the first sideband component.
7. The communication apparatus defined in claim 1 wherein the audio predistortion filter is a low-pass filter.
8. The communication apparatus defined in claim 7 wherein the audio predistortion filter is a digital processor.
9. The communication apparatus defined in claim 1 wherein:
the square root processor is a diode biased by a voltage source, in series with a resistance, whereby
a voltage across the diode is proportional to a square root of the second output signal a(t)As(t)+A.
10. The communication apparatus defined in claim 1 wherein the modulator is a balanced modulator.
11. The communication apparatus defined in claim 1 wherein:
the audio signal a(t) includes a high frequency component; and
the audio predistortion filter de-emphasizes the high frequency component by approximately 40 dB per decade.
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Description
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BACKGROUND OF THE INVENTION
This invention relates to the modulating of signals on carriers, which are transmitted and the signals intelligibly recovered, and more particularly, to the modulation of speech on a carrier and the intelligible recover of the speech by means of the Radio Frequency Hearing Effect.
The Radio Frequency ("RF") Hearing Effect was first noticed during World War II as a subjective "click" produced by a pulsed radar signal when the transmitted power is above a "threshold" level. Below the threshold level, the click cannot be heard.
The discovery of the Radio Frequency Hearing Effect suggested that a pulsed RF carrier could be encoded with an amplitude modulated ("AM") envelope. In one approach to pulsed carrier modulation, it was assumed that the "click" of the pulsed carrier was similar to a data sample and could be used to synthesize both simple and complex tones such as speech. Although pulsed carrier modulation can induce a subjective sensation for simple tones, it severely distorts the complex waveforms of speech, as has been confirmed experimentally.
The presence of this kind of distortion has prevented the click process for the encoding of intelligible speech. An example is provided by AM sampled data modulation
Upon demodulation the perceived speech signal has some of the envelope characteristics of an audio signal. Consequently a message can be recognized as speech when a listener is pre-advised that speech has been sent. However, if the listener does not know the content of the message, the audio signal is unintelligible.
The attempt to use the click process to encode speech has been based on the assumption that if simple tones can be encoded, speech can be encoded as well, but this is not so. A simple tone can contain several distortions and still be perceived as a tone whereas the same degree of distortion applied to speech renders it unintelligible.
SUMMARY OF THE INVENTION
In accomplishing the foregoing and related object the invention uses a modulation process with a fully suppressed carrier and pre-processor filtering of the input to produce an encoded output. Where amplitude modulation (AM) is employed and the pre-processor filtering is of audio speech input, intelligible subjective sound is produced when the encoded signal is demodulated by means of the RF Hearing Effect. Suitable forms of carrier suppressed modulation include single sideband (SSB) and carrier suppressed amplitude modulation (CSAM), with both sidebands present.
The invention further provides for analysis of the RE hearing phenomena based on an RF to acoustic transducer model. Analysis of the model suggests a new modulation process which permits the RF Hearing Effect to be used following the transmission of encoded speech.
In accordance with one aspect of the invention the preprocessing of an input speech signal takes place with a filter that de-emphasizes the high frequency content of the input speech signal. The de-emphasis can provide a signal reduction of about 40 dB (decibels) per decade. Further processing of the speech signal then takes place by adding a bias level and taking a root of the predistorted waveform. The resultant signal is used to modulated an RF carrier in the AM fully suppressed carrier mode, with single or double sidebands.
The modulated RF signal is demodulated by an RF to acoustic demodulator that produces an intelligible acoustic replication of the original input speech.
The RF Hearing Effect is explained and analyzed as a thermal to acoustic demodulating process. Energy absorption in a medium, such as the head, causes mechanical expansion and contraction, and thus an acoustic signal.
When the expansion and contraction take place in the head of an animal, the acoustic signal is passed by conduction to the inner ear where it is further processed as if it were an acoustic signal from the outer ear.
The RF to Acoustic Demodulator thus has characteristics which permit the conversion of the RF energy input to an acoustic output.
Accordingly, it is an object of the invention to provide a novel technique for the intelligible encoding of signals. A related object is to provide for the intelligible encoding of speech.
Another object of the invention is to make use of the Radio Frequency ("RF") Hearing Effect in the intelligible demodulation of encoded signals, including speech.
Still another object of the invention is to suitably encode a pulsed RF carrier with an amplitude modulated ("AM") envelope such that the modulation will be intelligibly demodulated by means of the RF Hearing Effect. A related object is to permit a message to be identified and understood as speech when a listener does not know beforehand that the message is speech.
Other aspects of the invention will be come apparent after considering several illustrative embodiments, taken in conjunction with the drawings.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram model of RF to Acoustic Demodulation Process making use of the Radio Frequency ("RF") Hearing Effect;
FIG. 2 is a spherical demodulator and radiator having a specific acoustic impedance for demodulation using the RF Hearing Effect;
FIG. 3 is a diagram illustrating the overall process and constituents of the invention; and
FIG. 4 is an illustrative circuit and wiring diagram for the components of FIG. 3.
DETAINED DESCRIPTION OF THE PREFERRED EMBODIMENT
With reference to the drawings, FIG. 1 illustrates the RF to acoustic demodulation process of the invention. Ordinarily an acoustic signal A reaches the outer ear E of the head H and traverses first to the inner ear I and then to the acoustic receptors of the brain B. A modulated RF signal, however, enters a demodulator D, which is illustratively provided by the mass M of the brain, and is approximated, as shown in FIG. 2, by a sphere S of radius r in the head H. The radius r of the sphere S is about 7 cm to make the sphere S equivalent to about the volume of the brain B. It will be appreciated that where the demodulator D, which can be an external component, is not employed with the acoustic receptors of the brain B, it can have other forms.
The sphere S, or its equivalent ellipsoid or similar solid, absorbs RF power which causes an increase in temperature that in turn causes an expansion and contraction which results in an acoustic wave. As a first approximation, it is assumed that the RF power is absorbed uniformly in the brain. Where the demodulator D is external to the brain B, the medium and/or RF carrier frequency can be selected to assure sufficiently uniform absorption.
For the modulated RF signal of FIG. 1, the power absorbed in the sphere S is proportional to the power waveform of the modulated RF signal. The absorption rate is characterized quantitatively in terms of the SAR (Specific Absorption Rate) in the units of absorbed watts per kilogram per incident watt per square centimeter.
The temperature of the sphere S is taken as following the integrated heat input from the power waveform, i.e. the process is approximated as being adiabatic, at least for short term intervals on the order of a few minutes.
The radial expansion of the sphere follows temperature and is converted to sound pressure, p(t), determined by the radial velocity (U.sub.r) multiplied by the real part of the specific acoustic impedance (Z.sub.s) of the sphere, as indicated in equation (1), below.
Z.sub.s =.rho..sub.o c(jkr)/(1+jkr)=.rho..sub.o c jf/f.sub.c /(1+jf/f.sub.c) (1)
Where:
.rho..sub.o =density, 1000 kg/m.sup.3 for water
c=speed of sound, 1560 m/s, in water @ 37.degree. C.
k=wave number, 2.pi./wavelength
r=sphere radius, in meters (m)
f=audio frequency
f.sub.c =lower cutoff break frequency,=c/(2.pi.r)
j=the 90 degree phase-shift operator
The specific acoustic impedance for a sphere of 7 cm radius, on the order of the size of the brain, has a lower cut-off break frequency of about 3,547 Hertz (Hz) for the parameters given for equation (1). The essential frequency range of speech is about 300 to 3000 Hz, i.e., below the cut-off frequency. It is therefore the Real part (R.sub.e) of Z.sub.s times the radial particle velocity (U.sub.r) which determines the sound pressure, p(t). The real part of Z.sub.s is given by equation (1a), below:
R.sub.e (Z.sub.s)=.rho..sub.o c(f/f.sub.c).sup.2 /(1+(f/f.sub.c).sup.2) (1a)
In the speech spectrum, which is below the brain cut-off frequency, the sphere S is an acoustic filter which "rolls off", i.e. decreases in amplitude at -40 dB per decade with decreasing frequency. In addition to any other demodulation processes to be analyzed below, the filter characteristics of the sphere will modify the acoustic signal with a 40 dB per decade slope in favor of the high frequencies.
Results for an AM Modulated Single Tone
An RF carrier with amplitude A.sub.c at frequency .omega..sub.c is AM modulated 100 percent with a single tone audio signal at frequency .omega..sub.1. The voltage (time) equation of this modulated signal is given by equation (2), below:
V(t)=A.sub.c sin (.omega..sub.c t)(1+sin (.omega..sub.a t)) (2)
The power signal is V(t).sup.2 as given by equation (3), below:
P(t)=A.sub.c.sup.2 [3/4+sin(.omega..sub.3 t)-1/4 cos(2.omega..sub.3 t)-3/4 cos(2.omega..sub.c t)-cos(2.omega..sub.c t) sin(.omega..sub.3 t)+1/4 cos(2.omega..sub.c t) cos(2.omega..sub.3 t)] (3)
To find the energy absorbed in the sphere, the time integral of equation (3) is taken times absorption coefficient, K. The result is divided by the specific heat, SH to obtain the temperature of the sphere and then multiplied by the volume expansion coefficient, Mv to obtain the change in volume. The change in volume is related to the change in radius by equation (4), below:
dV/V=3dr/r (4)
To obtain the amplitude of the radius change, there is multiplication by the radius and division by three. The rms radial surface velocity, U.sub.r is determined by multiplying the time derivative by r and dividing by 2.sup.1/2. The result, U.sub.r, is proportional to the power function, P(t) in equation (5), below.
U.sub.r =0.3535 P(t)rKM.sub.v /(3SH) (5)
The acoustic pressure, p(t), is given in equation (6), below, as the result of multiplying equation (5) by the Real part of the specific acoustic impedance, R.sub.e (1).
p(t)=R.sub.e {Z.sub.s U.sub.r }=R.sub.e (Z.sub.s)U.sub.r (6)
The SPL (Sound Pressure Level), in acoustic dB, is approximated as 20 log[p(t)/2E-5]. The standard acoustic reference level of 2E-5 Newtons per square meter is based on a signal in air; however, the head has a water-like consistency. Therefore, the subjective level in acoustic dB is only approximate, but sufficient for first order accuracy.
In a single tone case the incident RF power, P(t), from equation (3) has two terms as shown in equation (7), below, which are in the hearing range.
sin(.omega..sub.a t)-1/4 cos(2.omega..sub.a t) (7)
This is converted to the acoustic pressure wave, p(t), by multiplying by the specific acoustic impedance calculated at the two frequencies. Therefore, the resulting pressure wave as indicated in equation (8), below, becomes
p(t)=C[Z.sub.s (.omega..sub.a)sin(.omega..sub.a t)-1/4Z.sub.s (2.omega..sub.a)cos(2.omega..sub.3 t)] (8)
The result is an audio frequency and a second harmonic at about 1/4 amplitude. Thus using an RF carrier, AM modulated by a single tone, the pressure wave audio signal will consist of the audio tone and a second harmonic at about -6 dB, if the specific acoustic impedances at the two frequencies are the same. However, from equation (1) the break frequency of a model 7 cm sphere is 3.547 Hz. Most of the speech spectrum is below this frequency therefore the specific acoustic impedance is reactive and the real component is given by equation (8a), below:
R.sub.e {Z.sub.s (f)}=.rho..sub.o c(f/f.sub.c).sup.2 /(1+(f/f.sub.c)) (8a)
Below the cutoff frequency the real part of the impedance varies as the square of the frequency or gives a boost of 40 dB per decade. Therefore, if the input modulation signal is 1 kHz, the second harmonic will have a boost of about 4 time in amplitude, or 12 dB, due to the variation of the real part of the specific acoustic impedance with frequency. So the second harmonic pressure term in equation (8) is actually four times the power or 6 dB higher than the fundamental term. If the second harmonic falls above the cutoff frequency then the boost begins to fall back to 0 dB. However, for most of the speech spectrum there is a sever distortion and strong boost of the high frequency distortion components.
Results for Two Tone AM Modulation Analysis
Because of the distortion attending single tone modulation, predistortion of the modulation could be attempted such that the resulting demodulated pressure wave will not contain harmonic distortion. This will not work, however, because of the non-linear cross-products of two-tone modulation are quite different from single tone modulation as shown below.
Nevertheless, two-tone modulation distortion provides an insight for the design of a corrective process for a complex modulation signal such as speech. The nature of the distortion is defined in terms of relative amplitudes and frequencies.
Equation (8b) is that of an AM modulated carrier for the two-tone case where .omega..sub.a1 and .omega..sub.a2 are of equal amplitude and together modulate the carrier to a maximum peak value of 100 percent. The total modulated RF signal is given by equation (8b), below:
V(t)=A.sub.c sin(.omega..sub.c t)[1+1/2 sin(.omega..sub.a1 t)+1/2 sin(.omega..sub.a2 t)]
The square of (8b) is the power signal, which has the same form as the particle velocity, U.sub.r (t), of equation (9), below.
From the square of (8b) the following frequencies and relative amplitudes are obtained for the particle velocity wave, U.sub.r (t), which are in the audio range;
U.sub.r (t)=C[sin(.omega..sub.a1 t)+sin(.omega..sub.a2 t)+1/4 cos((.omega..sub.a1 -.omega..sub.a2)(t) =1/4 cos((.omega..sub.a1 +.omega..sub.a2)t)-1/8 cos(2.omega..sub.a1 t)-1/8 cos(2.omega..sub.a2 t)] (9)
If the frequencies in equation (9) are below the cut-off frequency, the impedance boost correction will result in a pressure wave with relative amplitudes given in equation (9a), below:
p(t)=C'[sin(.omega..sub.a1 t)+b.sup.2 sin(.omega..sub.a2 t)+(1-b.sup.2)/4 cos((.omega..sub.a1 -.omega..sub.a2)t)+(1+b.sup.2)/4 cos((.omega..sub.a1 +.omega..sub.a2)t)-1/2 cos(2.omega..sub.a1)t)-b.sup.2 /2 cos(2.omega..sub.a2 t) (9a)
where: b=.omega..sub.a2 /.omega..sub.a1 and .omega..sub.a2 >.omega..sub.a1
Equation (9a) contains a correction factor, b, for the specific acoustic impedance variation with frequency. The first two terms of (9a) are the two tones of the input modulation with the relative amplitudes modified by the impedance correction factor. The other terms are the distortion cross products which are quite different from the single tone distortion case. In addition to the second harmonics, there are sum and difference frequencies. From this two-tone analysis it is obvious that more complex multiple tone modulations, such as speech, will be severely distorted with even more complicated cross-product and sum and difference components. This is not unexpected since the process which creates the distortion is nonlinear. This leads to the conclusion that a simple passive predistortion filter will not work on a speech signal modulated on an RF carrier by a conventional AM process, because the distortion is a function of the signal by a nonlinear process.
However, the serious distortion problem can be overcome by means of the invention which exploits the characteristics of a different type of RF modulation process in addition to special signal processing.
AM Modulation With Fully Suppressed Carrier for the Intelligible Encoding of Speech by the Invention for Compatibility With the RF Hearing Phenomena
The equation for AM modulation with a fully suppressed carrier is given by equation (10), below:
V(t)=a(t)sin(.omega..sub.c t) (10)
This modulation is commonly accomplished in hardware by means of a circuit known as a balanced modulator, as disclosed, for example in "Radio Engineering", Frederick E. Terman, p.481-3, McGraw-Hill, 1947.
The power signal has the same form as the particle velocity signal which is obtained from the square of equation (10) as shown in equation (11), below:
P(t)=C U.sub.r =a(t).sup.2 /2-(a(t).sup.2 /2)cos(2.omega..sub..chi. t)) (11)
From inspection of equations (10) and (11) it is seen that, if the input audio signal, a(t), is pre-processed by taking the square root and then modulating the carrier, the audio term in the particle velocity equation will be an exact, undistorted, replication of the input audio signal. Since the audio signal from a microphone is bipolar, it must be modified by adding a very low frequency (essential d.c.) bias term, A, such that the resultant sum, [a(t)+A]>0.0, is always positive. This is necessary in order to insure a real square root. The use of a custom digital speech processor implements the addition of the term A, i.e. as shown in equation (10*), below:
V(t)=(a(t)+A).sup.1/2 sin(.omega..sub.c t) (10*)
The pressure wave is given by equation (11*), below:
p(t)=C U.sub.r =A/2+a(t)/2-(a(t)/2)cos(2.omega..sub.c t)-(A/2)cos(2.omega..sub.c t) (11*)
When the second term of the pressure wave of equation (11*) is processed through the specific acoustic impedance it will result in the replication of the input audio signal but will be modified by the filter characteristics of the Real part of the specific acoustic impedance, R.sub.e {Z.sub.s (f)}, as given in equation (8a). The first term of equation (11*) is the d.c. bias, which is added to obtain a real square root; it will not be audible or cause distortion. The third and fourth terms of (11*) are a.c. terms at twice the carrier frequency and therefore will not distort or interfere with the audio range signal, a(t).
Since the filter characteristic of equation (7) is a linear process in amplitude, the audio input can be predistorted before the modulation is applied to the carrier and then the pressure or wound wave audio signal, which is the result of the velocity wave times the impedance function, R.sub.e {Z.sub.s (f)}, will be the true replication of the original input audio signal.
A diagram illustrating the overall system 30 and process of the invention is shown in FIG. 3. Then input signal a(t) is applied to an Audio Predistortion Filter 31 with a filter function As(f) to produce a signal a(t)As(f), which is applied to a Square Root Processor 32, providing an output=(a(t)As(f)+A).sup.1/2, which goes to a balanced modulator 33. The modulation process known as suppressed carrier, produces a double sideband output=(a(t)As(f)+A).sup.1/2 sin(.omega..sub.c t), where .omega..sub.c is the carrier frequency. If one of the sidebands and the carrier are suppressed (not shown) the result is single sideband (SSB) modulation and will function in the same manner discussed above for the purposes of implementing the invention. However, the AM double sideband suppressed carrier as described is more easily implemented.
The output of the balanced modulator is applied to a spherical demodulator 34, which recovers the input signal a(t) that is applied to the inner ear 35 and then to the acoustic receptors in the brain 36.
The various components 31-33 of FIG. 3 are easily implemented as shown, for example by the corresponding components 41-42 in FIG. 4, where the Filter 41 can take the form of a low pass filter, such as a constant-K filter formed by series inductor L and a shunt capacitor C. Other low-pass filters are shown, for example, in the ITT Federal Handbook, 4th Ed., 1949. As a result the filter output is AS(f) a 1/f.sup.2. The Root Processor 42 can be implemented by any square-law device, such as the diode D biased by a battery B and in series with a large impedance (resistance) R, so that the voltage developed across the diode D is proportional to the square root of the input voltage a(t)As(f). The balanced modulator 43, as discussed in Terman, op.cit., has symmetrical diodes A1 and A2 with the modulating voltage M applied in opposite phase to the diodes A1 and A2 through an input transformer T1, with the carrier, O, applied commonly to the diodes in the same phase, while the modulating signal is applied to the diodes in opposite phase so that the carrier cancels in the primary of the output transformer T2 and the secondary output is the desired double side band output.
Finally the Spherical Demodulator 45 is the brain as discussed above, or an equivalent mass that provides uniform expansion and contraction due to thermal effects of RF energy.
The invention provides a new and useful encoding for speech on an RF carrier such that the speech will be intelligible to a human subject by means of the RF hearing demodulation phenomena. Features of the invention include the use of AM fully suppressed carrier modulation, the preprocessing of an input speech signal be a compensation filter to de-emphasize the high frequency content by 40 dB per decade and the further processing of the audio signal by adding a bias terms to permit the taking of the square root of the signal before the AM suppressed carrier modulation process.
The invention may also be implemented using the same audio signal processing and Single Sideband (SSB) modulation in place of AM suppressed carrier modulation. The same signal processing may also be used on Conventional AM modulation contains both sideband and the carrier; however, there is a serious disadvantage. The carrier is always present with AM modulation, even when there is no signal. The carrier power does not contain any information but contributes substantially to the heating of the thermal-acoustic demodulator, i.e. the brain, which is undesirable. The degree of this extraneous heating is more than twice the heating caused by the signal or information power in the RF signal. Therefore conventional AM modulation is an inefficient and poor choice compared to the double side-band suppressed carrier and the SSB types of transmissions.
The invention further may be implemented using various degrees of speech compression commonly used with all types of AM modulation. Speech compression is implemented by raising the level of the low amplitude portions of the speech waveform and limiting or compressing the high peak amplitudes of the speech waveform. Speech compression increases the average power content of the waveform and thus loudness. Speech compression introduces some distortion, so that a balance must be made between the increase in distortion and the increase in loudness to obtain the optimum result.
Another implementation is by digital signal processing of the input signal through to the modulation of the RF carrier.
United States Patent 6,587,729
O'Loughlin , et al. July 1, 2003
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Apparatus for audibly communicating speech using the radio frequency hearing effect
Abstract
A modulation process with a fully suppressed carrier and input preprocessor filtering to produce an encoded output; for amplitude modulation (AM) and audio speech preprocessor filtering, intelligible subjective sound is produced when the encoded signal is demodulated using the RF Hearing Effect. Suitable forms of carrier suppressed modulation include single sideband (SSB) and carrier suppressed amplitude modulation (CSAM), with both sidebands present.
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Inventors: O'Loughlin; James P. (Placitas, NM); Loree; Diana L. (Albuquerque, NM)
Assignee: The United States of America as represented by the Secretary of the Air (Washington, DC)
Appl. No.: 131626
Filed: April 24, 2002
Current U.S. Class: 607/55; 128/897; 332/167; 381/151; 600/586
Intern'l Class: H03C 001/54
Field of Search: 332/167 381/151 607/56,55 340/384.1 600/559,23,586 128/897,898
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References Cited [Referenced By]
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U.S. Patent Documents
3563246 Feb., 1971 Puharich et al. 607/55.
3629521 Dec., 1971 Puharich et al. 607/56.
4835791 May., 1989 Daoud 375/301.
5450044 Sep., 1995 Hulick 332/103.
Primary Examiner: Schaetzle; Kennedy
Attorney, Agent or Firm: Skorich; James M.
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Goverment Interests
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The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment of any royalty thereon.
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Parent Case Text
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This application is a division of U.S. patent application Ser. No. 08/766,687 filed on Dec. 13, 1996, now U.S. Pat. No. 6,470,214, and claims the benefit of the foregoing filing date.
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Claims
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What is claimed is:
1. An apparatus for communicating an audio signal a(t), comprising:
an audio predistortion filter having a filter function As(f) for producing a first output signal a(t)As(t) from the audio signal a(t);
means for adding a bias A to the first output signal, to produce a second output signal a(t)As(f)+A;
a square root processor for producing a third output signal (a(t)As(f)+A).sup.1/2 responsive to the second output signal; and
a modulator for producing a double sideband output signal responsive to the third output signal, having a carrier frequency of .omega..sub.c, and being mathematically described by (a(t)As(f)+A).sup.1/2 sin(.omega..sub.c t); and
transmitting the double sideband output signal to a demodulator, whereby the audio signal a(t) is recovered from the double sideband output signal.
2. The communication apparatus defined in claim 1 wherein:
the double sideband output signal has RF power; and
the demodulator is for converting the RF power into acoustic pressure waves.
3. The communication apparatus defined in claim 2 wherein:
the demodulator converts the RF power into the acoustic pressure waves by means of thermal expansion and contraction, whereby
the acoustic pressure waves approximate the audio signal a(t).
4. The communication apparatus defined in claim 2 wherein the demodulator includes a mass that expands and contracts responsive to the RE power of the double sideband output signal.
5. The communication apparatus defined in claim 4 wherein the mass is approximately spherical.
6. The communication apparatus defined in claim 1 wherein:
the double sideband output signal is comprised of a first sideband component and a second sideband component; and
means for suppressing the second sideband component, whereby
the demodulator recovers the audio signal a(t) solely from the first sideband component.
7. The communication apparatus defined in claim 1 wherein the audio predistortion filter is a low-pass filter.
8. The communication apparatus defined in claim 7 wherein the audio predistortion filter is a digital processor.
9. The communication apparatus defined in claim 1 wherein:
the square root processor is a diode biased by a voltage source, in series with a resistance, whereby
a voltage across the diode is proportional to a square root of the second output signal a(t)As(t)+A.
10. The communication apparatus defined in claim 1 wherein the modulator is a balanced modulator.
11. The communication apparatus defined in claim 1 wherein:
the audio signal a(t) includes a high frequency component; and
the audio predistortion filter de-emphasizes the high frequency component by approximately 40 dB per decade.
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Description
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BACKGROUND OF THE INVENTION
This invention relates to the modulating of signals on carriers, which are transmitted and the signals intelligibly recovered, and more particularly, to the modulation of speech on a carrier and the intelligible recover of the speech by means of the Radio Frequency Hearing Effect.
The Radio Frequency ("RF") Hearing Effect was first noticed during World War II as a subjective "click" produced by a pulsed radar signal when the transmitted power is above a "threshold" level. Below the threshold level, the click cannot be heard.
The discovery of the Radio Frequency Hearing Effect suggested that a pulsed RF carrier could be encoded with an amplitude modulated ("AM") envelope. In one approach to pulsed carrier modulation, it was assumed that the "click" of the pulsed carrier was similar to a data sample and could be used to synthesize both simple and complex tones such as speech. Although pulsed carrier modulation can induce a subjective sensation for simple tones, it severely distorts the complex waveforms of speech, as has been confirmed experimentally.
The presence of this kind of distortion has prevented the click process for the encoding of intelligible speech. An example is provided by AM sampled data modulation
Upon demodulation the perceived speech signal has some of the envelope characteristics of an audio signal. Consequently a message can be recognized as speech when a listener is pre-advised that speech has been sent. However, if the listener does not know the content of the message, the audio signal is unintelligible.
The attempt to use the click process to encode speech has been based on the assumption that if simple tones can be encoded, speech can be encoded as well, but this is not so. A simple tone can contain several distortions and still be perceived as a tone whereas the same degree of distortion applied to speech renders it unintelligible.
SUMMARY OF THE INVENTION
In accomplishing the foregoing and related object the invention uses a modulation process with a fully suppressed carrier and pre-processor filtering of the input to produce an encoded output. Where amplitude modulation (AM) is employed and the pre-processor filtering is of audio speech input, intelligible subjective sound is produced when the encoded signal is demodulated by means of the RF Hearing Effect. Suitable forms of carrier suppressed modulation include single sideband (SSB) and carrier suppressed amplitude modulation (CSAM), with both sidebands present.
The invention further provides for analysis of the RE hearing phenomena based on an RF to acoustic transducer model. Analysis of the model suggests a new modulation process which permits the RF Hearing Effect to be used following the transmission of encoded speech.
In accordance with one aspect of the invention the preprocessing of an input speech signal takes place with a filter that de-emphasizes the high frequency content of the input speech signal. The de-emphasis can provide a signal reduction of about 40 dB (decibels) per decade. Further processing of the speech signal then takes place by adding a bias level and taking a root of the predistorted waveform. The resultant signal is used to modulated an RF carrier in the AM fully suppressed carrier mode, with single or double sidebands.
The modulated RF signal is demodulated by an RF to acoustic demodulator that produces an intelligible acoustic replication of the original input speech.
The RF Hearing Effect is explained and analyzed as a thermal to acoustic demodulating process. Energy absorption in a medium, such as the head, causes mechanical expansion and contraction, and thus an acoustic signal.
When the expansion and contraction take place in the head of an animal, the acoustic signal is passed by conduction to the inner ear where it is further processed as if it were an acoustic signal from the outer ear.
The RF to Acoustic Demodulator thus has characteristics which permit the conversion of the RF energy input to an acoustic output.
Accordingly, it is an object of the invention to provide a novel technique for the intelligible encoding of signals. A related object is to provide for the intelligible encoding of speech.
Another object of the invention is to make use of the Radio Frequency ("RF") Hearing Effect in the intelligible demodulation of encoded signals, including speech.
Still another object of the invention is to suitably encode a pulsed RF carrier with an amplitude modulated ("AM") envelope such that the modulation will be intelligibly demodulated by means of the RF Hearing Effect. A related object is to permit a message to be identified and understood as speech when a listener does not know beforehand that the message is speech.
Other aspects of the invention will be come apparent after considering several illustrative embodiments, taken in conjunction with the drawings.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram model of RF to Acoustic Demodulation Process making use of the Radio Frequency ("RF") Hearing Effect;
FIG. 2 is a spherical demodulator and radiator having a specific acoustic impedance for demodulation using the RF Hearing Effect;
FIG. 3 is a diagram illustrating the overall process and constituents of the invention; and
FIG. 4 is an illustrative circuit and wiring diagram for the components of FIG. 3.
DETAINED DESCRIPTION OF THE PREFERRED EMBODIMENT
With reference to the drawings, FIG. 1 illustrates the RF to acoustic demodulation process of the invention. Ordinarily an acoustic signal A reaches the outer ear E of the head H and traverses first to the inner ear I and then to the acoustic receptors of the brain B. A modulated RF signal, however, enters a demodulator D, which is illustratively provided by the mass M of the brain, and is approximated, as shown in FIG. 2, by a sphere S of radius r in the head H. The radius r of the sphere S is about 7 cm to make the sphere S equivalent to about the volume of the brain B. It will be appreciated that where the demodulator D, which can be an external component, is not employed with the acoustic receptors of the brain B, it can have other forms.
The sphere S, or its equivalent ellipsoid or similar solid, absorbs RF power which causes an increase in temperature that in turn causes an expansion and contraction which results in an acoustic wave. As a first approximation, it is assumed that the RF power is absorbed uniformly in the brain. Where the demodulator D is external to the brain B, the medium and/or RF carrier frequency can be selected to assure sufficiently uniform absorption.
For the modulated RF signal of FIG. 1, the power absorbed in the sphere S is proportional to the power waveform of the modulated RF signal. The absorption rate is characterized quantitatively in terms of the SAR (Specific Absorption Rate) in the units of absorbed watts per kilogram per incident watt per square centimeter.
The temperature of the sphere S is taken as following the integrated heat input from the power waveform, i.e. the process is approximated as being adiabatic, at least for short term intervals on the order of a few minutes.
The radial expansion of the sphere follows temperature and is converted to sound pressure, p(t), determined by the radial velocity (U.sub.r) multiplied by the real part of the specific acoustic impedance (Z.sub.s) of the sphere, as indicated in equation (1), below.
Z.sub.s =.rho..sub.o c(jkr)/(1+jkr)=.rho..sub.o c jf/f.sub.c /(1+jf/f.sub.c) (1)
Where:
.rho..sub.o =density, 1000 kg/m.sup.3 for water
c=speed of sound, 1560 m/s, in water @ 37.degree. C.
k=wave number, 2.pi./wavelength
r=sphere radius, in meters (m)
f=audio frequency
f.sub.c =lower cutoff break frequency,=c/(2.pi.r)
j=the 90 degree phase-shift operator
The specific acoustic impedance for a sphere of 7 cm radius, on the order of the size of the brain, has a lower cut-off break frequency of about 3,547 Hertz (Hz) for the parameters given for equation (1). The essential frequency range of speech is about 300 to 3000 Hz, i.e., below the cut-off frequency. It is therefore the Real part (R.sub.e) of Z.sub.s times the radial particle velocity (U.sub.r) which determines the sound pressure, p(t). The real part of Z.sub.s is given by equation (1a), below:
R.sub.e (Z.sub.s)=.rho..sub.o c(f/f.sub.c).sup.2 /(1+(f/f.sub.c).sup.2) (1a)
In the speech spectrum, which is below the brain cut-off frequency, the sphere S is an acoustic filter which "rolls off", i.e. decreases in amplitude at -40 dB per decade with decreasing frequency. In addition to any other demodulation processes to be analyzed below, the filter characteristics of the sphere will modify the acoustic signal with a 40 dB per decade slope in favor of the high frequencies.
Results for an AM Modulated Single Tone
An RF carrier with amplitude A.sub.c at frequency .omega..sub.c is AM modulated 100 percent with a single tone audio signal at frequency .omega..sub.1. The voltage (time) equation of this modulated signal is given by equation (2), below:
V(t)=A.sub.c sin (.omega..sub.c t)(1+sin (.omega..sub.a t)) (2)
The power signal is V(t).sup.2 as given by equation (3), below:
P(t)=A.sub.c.sup.2 [3/4+sin(.omega..sub.3 t)-1/4 cos(2.omega..sub.3 t)-3/4 cos(2.omega..sub.c t)-cos(2.omega..sub.c t) sin(.omega..sub.3 t)+1/4 cos(2.omega..sub.c t) cos(2.omega..sub.3 t)] (3)
To find the energy absorbed in the sphere, the time integral of equation (3) is taken times absorption coefficient, K. The result is divided by the specific heat, SH to obtain the temperature of the sphere and then multiplied by the volume expansion coefficient, Mv to obtain the change in volume. The change in volume is related to the change in radius by equation (4), below:
dV/V=3dr/r (4)
To obtain the amplitude of the radius change, there is multiplication by the radius and division by three. The rms radial surface velocity, U.sub.r is determined by multiplying the time derivative by r and dividing by 2.sup.1/2. The result, U.sub.r, is proportional to the power function, P(t) in equation (5), below.
U.sub.r =0.3535 P(t)rKM.sub.v /(3SH) (5)
The acoustic pressure, p(t), is given in equation (6), below, as the result of multiplying equation (5) by the Real part of the specific acoustic impedance, R.sub.e (1).
p(t)=R.sub.e {Z.sub.s U.sub.r }=R.sub.e (Z.sub.s)U.sub.r (6)
The SPL (Sound Pressure Level), in acoustic dB, is approximated as 20 log[p(t)/2E-5]. The standard acoustic reference level of 2E-5 Newtons per square meter is based on a signal in air; however, the head has a water-like consistency. Therefore, the subjective level in acoustic dB is only approximate, but sufficient for first order accuracy.
In a single tone case the incident RF power, P(t), from equation (3) has two terms as shown in equation (7), below, which are in the hearing range.
sin(.omega..sub.a t)-1/4 cos(2.omega..sub.a t) (7)
This is converted to the acoustic pressure wave, p(t), by multiplying by the specific acoustic impedance calculated at the two frequencies. Therefore, the resulting pressure wave as indicated in equation (8), below, becomes
p(t)=C[Z.sub.s (.omega..sub.a)sin(.omega..sub.a t)-1/4Z.sub.s (2.omega..sub.a)cos(2.omega..sub.3 t)] (8)
The result is an audio frequency and a second harmonic at about 1/4 amplitude. Thus using an RF carrier, AM modulated by a single tone, the pressure wave audio signal will consist of the audio tone and a second harmonic at about -6 dB, if the specific acoustic impedances at the two frequencies are the same. However, from equation (1) the break frequency of a model 7 cm sphere is 3.547 Hz. Most of the speech spectrum is below this frequency therefore the specific acoustic impedance is reactive and the real component is given by equation (8a), below:
R.sub.e {Z.sub.s (f)}=.rho..sub.o c(f/f.sub.c).sup.2 /(1+(f/f.sub.c)) (8a)
Below the cutoff frequency the real part of the impedance varies as the square of the frequency or gives a boost of 40 dB per decade. Therefore, if the input modulation signal is 1 kHz, the second harmonic will have a boost of about 4 time in amplitude, or 12 dB, due to the variation of the real part of the specific acoustic impedance with frequency. So the second harmonic pressure term in equation (8) is actually four times the power or 6 dB higher than the fundamental term. If the second harmonic falls above the cutoff frequency then the boost begins to fall back to 0 dB. However, for most of the speech spectrum there is a sever distortion and strong boost of the high frequency distortion components.
Results for Two Tone AM Modulation Analysis
Because of the distortion attending single tone modulation, predistortion of the modulation could be attempted such that the resulting demodulated pressure wave will not contain harmonic distortion. This will not work, however, because of the non-linear cross-products of two-tone modulation are quite different from single tone modulation as shown below.
Nevertheless, two-tone modulation distortion provides an insight for the design of a corrective process for a complex modulation signal such as speech. The nature of the distortion is defined in terms of relative amplitudes and frequencies.
Equation (8b) is that of an AM modulated carrier for the two-tone case where .omega..sub.a1 and .omega..sub.a2 are of equal amplitude and together modulate the carrier to a maximum peak value of 100 percent. The total modulated RF signal is given by equation (8b), below:
V(t)=A.sub.c sin(.omega..sub.c t)[1+1/2 sin(.omega..sub.a1 t)+1/2 sin(.omega..sub.a2 t)]
The square of (8b) is the power signal, which has the same form as the particle velocity, U.sub.r (t), of equation (9), below.
From the square of (8b) the following frequencies and relative amplitudes are obtained for the particle velocity wave, U.sub.r (t), which are in the audio range;
U.sub.r (t)=C[sin(.omega..sub.a1 t)+sin(.omega..sub.a2 t)+1/4 cos((.omega..sub.a1 -.omega..sub.a2)(t) =1/4 cos((.omega..sub.a1 +.omega..sub.a2)t)-1/8 cos(2.omega..sub.a1 t)-1/8 cos(2.omega..sub.a2 t)] (9)
If the frequencies in equation (9) are below the cut-off frequency, the impedance boost correction will result in a pressure wave with relative amplitudes given in equation (9a), below:
p(t)=C'[sin(.omega..sub.a1 t)+b.sup.2 sin(.omega..sub.a2 t)+(1-b.sup.2)/4 cos((.omega..sub.a1 -.omega..sub.a2)t)+(1+b.sup.2)/4 cos((.omega..sub.a1 +.omega..sub.a2)t)-1/2 cos(2.omega..sub.a1)t)-b.sup.2 /2 cos(2.omega..sub.a2 t) (9a)
where: b=.omega..sub.a2 /.omega..sub.a1 and .omega..sub.a2 >.omega..sub.a1
Equation (9a) contains a correction factor, b, for the specific acoustic impedance variation with frequency. The first two terms of (9a) are the two tones of the input modulation with the relative amplitudes modified by the impedance correction factor. The other terms are the distortion cross products which are quite different from the single tone distortion case. In addition to the second harmonics, there are sum and difference frequencies. From this two-tone analysis it is obvious that more complex multiple tone modulations, such as speech, will be severely distorted with even more complicated cross-product and sum and difference components. This is not unexpected since the process which creates the distortion is nonlinear. This leads to the conclusion that a simple passive predistortion filter will not work on a speech signal modulated on an RF carrier by a conventional AM process, because the distortion is a function of the signal by a nonlinear process.
However, the serious distortion problem can be overcome by means of the invention which exploits the characteristics of a different type of RF modulation process in addition to special signal processing.
AM Modulation With Fully Suppressed Carrier for the Intelligible Encoding of Speech by the Invention for Compatibility With the RF Hearing Phenomena
The equation for AM modulation with a fully suppressed carrier is given by equation (10), below:
V(t)=a(t)sin(.omega..sub.c t) (10)
This modulation is commonly accomplished in hardware by means of a circuit known as a balanced modulator, as disclosed, for example in "Radio Engineering", Frederick E. Terman, p.481-3, McGraw-Hill, 1947.
The power signal has the same form as the particle velocity signal which is obtained from the square of equation (10) as shown in equation (11), below:
P(t)=C U.sub.r =a(t).sup.2 /2-(a(t).sup.2 /2)cos(2.omega..sub..chi. t)) (11)
From inspection of equations (10) and (11) it is seen that, if the input audio signal, a(t), is pre-processed by taking the square root and then modulating the carrier, the audio term in the particle velocity equation will be an exact, undistorted, replication of the input audio signal. Since the audio signal from a microphone is bipolar, it must be modified by adding a very low frequency (essential d.c.) bias term, A, such that the resultant sum, [a(t)+A]>0.0, is always positive. This is necessary in order to insure a real square root. The use of a custom digital speech processor implements the addition of the term A, i.e. as shown in equation (10*), below:
V(t)=(a(t)+A).sup.1/2 sin(.omega..sub.c t) (10*)
The pressure wave is given by equation (11*), below:
p(t)=C U.sub.r =A/2+a(t)/2-(a(t)/2)cos(2.omega..sub.c t)-(A/2)cos(2.omega..sub.c t) (11*)
When the second term of the pressure wave of equation (11*) is processed through the specific acoustic impedance it will result in the replication of the input audio signal but will be modified by the filter characteristics of the Real part of the specific acoustic impedance, R.sub.e {Z.sub.s (f)}, as given in equation (8a). The first term of equation (11*) is the d.c. bias, which is added to obtain a real square root; it will not be audible or cause distortion. The third and fourth terms of (11*) are a.c. terms at twice the carrier frequency and therefore will not distort or interfere with the audio range signal, a(t).
Since the filter characteristic of equation (7) is a linear process in amplitude, the audio input can be predistorted before the modulation is applied to the carrier and then the pressure or wound wave audio signal, which is the result of the velocity wave times the impedance function, R.sub.e {Z.sub.s (f)}, will be the true replication of the original input audio signal.
A diagram illustrating the overall system 30 and process of the invention is shown in FIG. 3. Then input signal a(t) is applied to an Audio Predistortion Filter 31 with a filter function As(f) to produce a signal a(t)As(f), which is applied to a Square Root Processor 32, providing an output=(a(t)As(f)+A).sup.1/2, which goes to a balanced modulator 33. The modulation process known as suppressed carrier, produces a double sideband output=(a(t)As(f)+A).sup.1/2 sin(.omega..sub.c t), where .omega..sub.c is the carrier frequency. If one of the sidebands and the carrier are suppressed (not shown) the result is single sideband (SSB) modulation and will function in the same manner discussed above for the purposes of implementing the invention. However, the AM double sideband suppressed carrier as described is more easily implemented.
The output of the balanced modulator is applied to a spherical demodulator 34, which recovers the input signal a(t) that is applied to the inner ear 35 and then to the acoustic receptors in the brain 36.
The various components 31-33 of FIG. 3 are easily implemented as shown, for example by the corresponding components 41-42 in FIG. 4, where the Filter 41 can take the form of a low pass filter, such as a constant-K filter formed by series inductor L and a shunt capacitor C. Other low-pass filters are shown, for example, in the ITT Federal Handbook, 4th Ed., 1949. As a result the filter output is AS(f) a 1/f.sup.2. The Root Processor 42 can be implemented by any square-law device, such as the diode D biased by a battery B and in series with a large impedance (resistance) R, so that the voltage developed across the diode D is proportional to the square root of the input voltage a(t)As(f). The balanced modulator 43, as discussed in Terman, op.cit., has symmetrical diodes A1 and A2 with the modulating voltage M applied in opposite phase to the diodes A1 and A2 through an input transformer T1, with the carrier, O, applied commonly to the diodes in the same phase, while the modulating signal is applied to the diodes in opposite phase so that the carrier cancels in the primary of the output transformer T2 and the secondary output is the desired double side band output.
Finally the Spherical Demodulator 45 is the brain as discussed above, or an equivalent mass that provides uniform expansion and contraction due to thermal effects of RF energy.
The invention provides a new and useful encoding for speech on an RF carrier such that the speech will be intelligible to a human subject by means of the RF hearing demodulation phenomena. Features of the invention include the use of AM fully suppressed carrier modulation, the preprocessing of an input speech signal be a compensation filter to de-emphasize the high frequency content by 40 dB per decade and the further processing of the audio signal by adding a bias terms to permit the taking of the square root of the signal before the AM suppressed carrier modulation process.
The invention may also be implemented using the same audio signal processing and Single Sideband (SSB) modulation in place of AM suppressed carrier modulation. The same signal processing may also be used on Conventional AM modulation contains both sideband and the carrier; however, there is a serious disadvantage. The carrier is always present with AM modulation, even when there is no signal. The carrier power does not contain any information but contributes substantially to the heating of the thermal-acoustic demodulator, i.e. the brain, which is undesirable. The degree of this extraneous heating is more than twice the heating caused by the signal or information power in the RF signal. Therefore conventional AM modulation is an inefficient and poor choice compared to the double side-band suppressed carrier and the SSB types of transmissions.
The invention further may be implemented using various degrees of speech compression commonly used with all types of AM modulation. Speech compression is implemented by raising the level of the low amplitude portions of the speech waveform and limiting or compressing the high peak amplitudes of the speech waveform. Speech compression increases the average power content of the waveform and thus loudness. Speech compression introduces some distortion, so that a balance must be made between the increase in distortion and the increase in loudness to obtain the optimum result.
Another implementation is by digital signal processing of the input signal through to the modulation of the RF carrier.
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