USPTO Patents related to Class E transmitters

[AB2EZ]

This is, I believe, one of the earliest patents granted by the US Patent and Trademark Office for transmitters that employ a class E RF output stage... either pulse width modulated or linearly modulated.

http://patft.uspto.gov/netacgi/nph-Parser?Sect2=PTO1&Sect2=HITOFF&p=1&u=%2Fnetahtml%2FPTO%2Fsearch-bool.html&r=1&f=G&l=50&d=PALL&RefSrch=yes&Query=PN%2F3919656

The filing date is April 23, 1973... at a time when patents (exclusive rights to sell and/or use what was "claimed" as an invention) were granted for 17 years subsequent to the filing date. As per US patent law... each "claim" (in its entirety) is a separately enforceable patented invention. Starting 17 years after the filing date (expiration of the patent), anyone can "practice" what is claimed (e.g. sell or use an implementation of what was claimed) without limitation.

Since this (expired) patent was granted. there have been numerous (hundreds) of additional patents filed and granted... many of which have not yet expired... on many "improvements" or specific embellishments.

I suspect that most of those could (at great expense... typically more than $1M in legal fees) be challenged... and ruled (by a court) to be invalid... because what was claimed was either "anticipated" (previously disclosed in some form of publication) or "obvious" (a combination of things that were previously disclosed; and which someone skilled in the art would have been motivated to combine).

Thus, it is not surprising that anyone who tries to manufacture and sell a Class E transmitter would be informed that he is infringing on someone's patent(s).

Usually, the holder of a patent would only "go after" someone who is making a lot of money selling (or using) the alleged infringing product.. but if the alleged infringers include a mix of "big guys" and "little guys"... the patent holder would typically contact all of them in order to demonstrate that he is being diligent in enforcing his patent(s).

Stu

[W2WDX]

... And so it goes. Sorry Mr. Sarnoff, I didn't mean to steal your cookies!!!

John

[Steve - K4HX]

Who is being informed of infringement?

[k4kyv]

... patents (exclusive rights to sell and/or use what was "claimed" as an invention) were granted for 17 years subsequent to the filing date... 

I have a problem with that.  Regardless of patent issues, no-one can stop me from studying available published information, purchasing the parts, and constructing a device or circuit for my own personal use on my own property.

[W2WDX]

No Don they can't nor would they. It's when you try to have a pecuniary interest, like if you were building the "The Donald - Class E AM Transmitter", and market it for sale. That's when the dogs come scrounging for scraps.

Patents exist because of money, not to control knowledge. And patent enforcement is not about the use of the idea, only any profit made from it.

If it's DIY, and no profit is being made, why would they care? They don't.

John

[WA1GFZ]

OTOH a patent protects the inventor from some clown coming along and slapping his name on the inventor's idea. Then making money and fame from someone else's work.

[W2NBC]

Class E Kits

http://www.wa0itp.com/ns40.html
http://www.swlink.net/~w5jh/azsx303e.htm
http://www.sstran.com/
http://www.grumpyshop.net/index.php?main_page=product_info&cPath=100&products_id=516&zenid=0e526101647a088c3e38f90e798d256d
http://www.cqdx.ru/ham/new-equipment/amt5000-high-efficiency-pro-am-radio-transmitter-kit/

Class E Assembled:
http://www.sgcworld.com/minilinistory.html
http://www.nationalxmtr.com/shortwave-transmitters.php


From the SGC website:

"The final event that made a huge impact in the development of the MINI LINI occurred in 1975 when Nathan Sokal patented the class E amplifier. His non-linear amplifier was capable of close to 90% efficiency in practical circuits. The pairing of class E technology and the EER method is how very efficient SSB transmitters became possible. For many years, shortwave SSB broadcast transmitters of 100 KW and more have been in regular use, proving this technology to be highly reliable."

The only reference to "patented" regarding Class E in current production is Broadcast Electronics:
"Exclusive, patented class E power module"..

http://www.bdcast.com/products/details/a-series/am-500a#tabs-1


With the current manufacturers having some "economic gain" I wonder if they ALL received non-disclosure statements..

There are quite a few manufacturers of Commercial Broadcast and Shortwave transmitters using this technology. If they had to pay BE (Broadcast Electronics) a waiver, I'm not sure. It's ALL a little curious..INDEED

[Steve - K4HX]

What's curious? Who has received any notice of infringement or other legal paperwork? Why did Stu post this?

[W2NBC]

Steve

http://amfone.net/Amforum/index.php?topic=30826.msg240396#msg240396

I think that might have been the reason..

[W2WDX]

There are hundreds of patents for Class E HF AM stuff. B.E. just mentions it in its marketing. I was presented with about 20 separate relevant patents from one company.

I am sure many of you guys have radios that use exactly what is found in some of these patents. I feel for Steve QIX since it's unlikely if he ever did want to pursue production radios, he probably wouldn't be able to.

John

[W2WDX]

OTOH a patent protects the inventor from some clown coming along and slapping his name on the inventor's idea. Then making money and fame from someone else's work.

Most times, it's the other way around. The process for applying for a patent is expensive and complex. Especially for electronic theory or devices. Most times large companies take the idea, patent it themselves and claim legal ownership of other peoples work. It costs millions to challenge a patent claim; Armstrong vs RCA is a famous testament to this folly. He won, but it took decades, was bankrupted by the legal challenge, and committed suicide as a result.

So if you have some new radical idea or design, don't put it up on the web. Yeah ... you hold the copyright on the article, but a company can take the idea in its entirety unchanged and apply for a patent on it. It's legal for them to do so. You then have no right to the idea unless you have the financial strength to challenge it in court.

[steve_qix]

I have looked at some of the patents.  The ones I saw come AFTER I published my material in the public domain.  In fact, I did have one conversation with a company I won't name who tried to patent something I had published!  Obviously, they did not do so after I pointed out that this has been in the public domain for a while now.

A lot of employees working for commercial companies appear to read the class E web site, because a lot of what I have designed is showing up in other stuff out there.

[Ed/KB1HYS]

Pecuniary interest.  I can study any patented device and build a copy, as long as it's my own work and I never sell it. I wonder if a 'public license' could be used kind of like what the linux and open source guys do.

I know the company I work for will own anything I care to patent, if I do not offer it to them first right of refusal (or something like that).  If I patent something related to the company, and I go through the company I would receive a (small) financial consideration and a nice plaque with the patent form engraved on it. Lots of the EE guys have them on their walls.   

I actually did think of patenting one item we made.  Too much work for me and it wasn't worth the effort for the rewards.  If it was worth something, the company would actually have one of the many lawyers who work in the legal dept handle all that...

[John K5PRO]

The Sokol's at Design Automation were the first to understand the implications of, and the theory of, a class E Rf generator, as documented in the early 1970s. They also did power supply design work, and wrote the HEPA class E simulator software, which Nathan marketed. He sold off a lot of parts and assets few years ago, getting out of the active lab work I think. I bought boxes of toroid cores, RF beads, teflon sheet, and a very nice Kikusui power supply from him.

[k4kyv]

I know the company I work for will own anything I care to patent, if I do not offer it to them first right of refusal (or something like that).  If I patent something related to the company, and I go through the company I would receive a (small) financial consideration and a nice plaque with the patent form engraved on it. Lots of the EE guys have them on their walls. 

I think that's pretty much a default clause in any employment contract.  Back in the 70s I worked for two different companies each of which had me sign an agreement that they owned anything I might try to patent. Allegedly, this was to "protect" the company, to prevent an employee from working on an idea on company time, using company facilities, that directly involved a company product, and then gaining a patent and charging the company to use the idea or else preventing them from ever developing the idea on their own.  But the way the contract was worded, even if I had patented something as far removed from the companies' lines of products as a flushing mechanism for a toilet, they still would have had claim to the patent even though their speciality was limited in one case to computer peripherals and the other to telecommunications hardware.

Since practically everyone, excluding the self-employed, unemployed and independently wealthy, must work somewhere for a living, that makes it even more difficult for some Hammy Hambone or Joe Bloe to ever have any hope of striking it rich with a patent on his own. I don't recall whether there was a patent clause in my public school teaching contract, but it wouldn't surprise me to find that there was.

I would say if you hit on a lucrative idea that you truly think is unique and no-one else has ever thought of, quit your job and sever all ties with the company before even beginning the paperwork for the patent.  It's possible that some patent clauses extend for a period after termination of employment, or maybe even for lifetime - something you might be able to beat in court, but since justice is a commodity that is bought and sold for a price (aka attorney fees and court costs), as in Armstrong's and Tesla's cases it would come at a great cost.

[The Slab Bacon]

the company that I now work (and have for the last 10 yrs now) for wanted me to sign a "non compete" agreement as part of the terms of employment.

I told them that I wouldn't sign anything like that without first having a (my) lawyer look at it first. He looked at it and told me that A- it was so poorly worded that it wasn't worth the paper it was written on. and B-in this state they are just about impossible to enforce.

I still gave it a lot of thought before making a decision. I ended up telling them to Go and pound sand into that certain opening you would expect me to say.
When they asked why I put up such a fuss, I told them:
"This is what I do, and I am not going to deprive myself of the ability to make a living or put food on my table if something would go wrong here." "If you want me you take me as I am and we both take our chances". They never pushed it any farther and I am still here many years later. Not to mention their highest rated estimator/salesman. They have long forgotten about it.

The irony of it all is that after 24 years in this line of business, I have pretty much had enough and am hitting the point of burnout. If something was to happen here, I would now probably look for employment in another field. (Still rendering no need for the "non compete" agreement.)

[k4kyv]

We are all familiar with the Tesla vs Marconi battle, and Armstrong vs RCA. Another inventor that Sarnoff and RCA tried to screw was Philo T Farnsworth, the father of all-electronic television.  Farnsworth won the case, but at great cost, even to the point of travelling to England to raise funds for his legal expenses.

Farnsworth designed and built the world's first working all-electronic television system, employing electronic scanning in both the pickup and display devices. He first demonstrated his system to the press on September 3, 1928.
In 1930, Vladimir Zworykin, who had been developing his own all-electronic television system at Westinghouse in Pittsburgh since 1923, but which he had never been able to make work or satisfactorily demonstrate to his superiors, was recruited by RCA to lead its television development department.

In 1931, David Sarnoff of RCA offered to buy Farnsworth's patents for $100,000, with the stipulation that he become an employee of RCA, but Farnsworth refused. In June of that year, Farnsworth joined the Philco company and moved to Philadelphia along with his wife and two children. RCA would later file an interference suit against Farnsworth, claiming Zworykin's 1923 patent had priority over Farnsworth's design, despite the fact it could present no evidence that Zworykin had actually produced a functioning transmitter tube before 1931. Farnsworth had lost two interference claims to Zworykin in 1928, but this time he prevailed and the U.S. Patent Office rendered a decision in 1934 awarding priority of the invention of the image dissector to Farnsworth. RCA lost a subsequent appeal, but litigation over a variety of issues continued for several years with Sarnoff finally agreeing to pay Farnsworth royalties.

In 1932, while in England to raise money for his legal battles with RCA, Farnsworth met with John Logie Baird, a Scottish inventor who had given the world first public demonstration of a working television system in London in 1926, using mechanical imaging systems, and who was seeking to develop electronic television receivers. Baird demonstrated his mechanical system for Farnsworth, and explained "the superiority of his system". But after watching several minutes of Farnsworth's version, "He advanced slowly, as if hypnotized, until he was standing directly before it, He stood there for some time; he turned without a word and left".

Farnsworth would have nothing to do with any so-called patent agreement. In 1924 he applied to the United States Naval Academy in Annapolis, Maryland, where he was recruited after he earned the nation's second highest score on academy tests. However, he was already thinking ahead to his television projects and, upon learning the government would own his patents if he stayed in the military, he sought and received an honorable discharge, returning to Utah to continue to help support his mother.

http://en.wikipedia.org/wiki/Philo_Farnsworth

[K5UJ]

Zworykin supposedly once said that if he had known ahead of time what kind of junk would be on TV, he would have never worked on it. 

To paraphrase Groucho Marx:  TV has taught me a lot about radio--when someone turns on a TV, I go away and read a book about electronics.