# Talk:Cathode-ray tube amusement device

This review is transcluded from Talk:Cathode ray tube amusement device/GA1. The edit link for this section can be used to add comments to the review.
Reviewer: Indrian (talk · contribs) 16:28, 23 January 2016 (UTC)
Okay, since no one is taking this one up, I will go ahead and review, as its the only one of PresN's excellent early video game articles still waiting for that GA tag.  Comments to follow shortly. Indrian (talk) 16:28, 23 January 2016 (UTC)


### Infobox
So about the name.  Cathode ray tube used to be a hyphenate, so the original patent calls it the cathode-ray tube amusement device.  It looks like most sources today drop the hyphen, though some keep it.  I don't know that its worth sweating a hyphen, but should the original styling appear somewhere in the article?  I don't know that our policies really speak to this, so I don't have a strong opinion either way.
Okay, I've been thinking about it for a couple days, and I've adjusted all the text to have the hyphen. Even if we don't use the hyphen nowadays (and many of the sources don't), the original patent had one and I think we should call it what it was actually called, not how we would spell it today. I'm going to hold off on moving the article itself until the review is finished, though, to avoid complications with this subpage moving. --PresN 17:18, 26 January 2016 (UTC)
"Patented 1947–1948" - I realize this is attempting to convey in shorthand that the patent was filed in 1947 and issued in 1948, but the term "patented" refers only to when the patent was actually issued, so this use of the term is incorrect and misleading.
Dropped, the infobox doesn't handle single dates right, only time periods. --PresN 17:18, 26 January 2016 (UTC)


### Lead
"The cathode ray tube amusement device is the earliest known interactive electronic game to use an electronic display" - Is this a little redundant?  I believe the CRT amusement device is the earliest electronic game period, which automatically makes it the first to use an electronic display.
There were electric pinball games in the 30s; the CRTAD's claim to fame is only that it had an electronic display instead of just physical interactions. It's a little hazy what the minimum definition of "electronic" is in regards to the pinball games, but while the about.com source calls the CRTAD the first electronic game patent, I'm hesitant to therefore declare it as such, rather than the more limited "first electronic game with an electronic display". If "electronic" means vacuum tubes, then maybe? But the earlier pinball games used electricity to run lights and solenoids. --PresN 17:26, 26 January 2016 (UTC)
Well, I contradict myself, don't I- the law journal source also says it's the first patent for an electronic game, and I state that outright. Okay, changed it to "first electronic game" everywhere, I'll need to adjust that in other articles later. --PresN 17:28, 26 January 2016 (UTC)
"The player simulates an artillery shell arcing towards targets" - The system simulates the artillery shell, the player controls it.  Needs to be changed to one or the other.
Fixed. --PresN 17:18, 26 January 2016 (UTC)
"adjusting knobs to control the trajectory of a CRT" - The abbreviation CRT has yet to be defined in the article at this point.
Fixed. --PresN 17:18, 26 January 2016 (UTC)


### Gameplay
"The cathode ray tube amusement device appears to the player as a cathode ray tube (CRT) connected to an oscilloscope, with a set of knobs and switches" - The term "appears as" generally means that something looks one way when it is actually something else.  Also, including "the player" here is somewhat awkward.  Perhaps "The cathode ray tube amusement device consists of"?
Fixed. --PresN 17:18, 26 January 2016 (UTC)
"does not use any memory device, digital computer, or programming" - Mixed list since the first two are objects and the third is not.  Perhaps "does not use any digital computer or memory device or execute a program"?
Done. --PresN 17:18, 26 January 2016 (UTC)
"are transparent plastic targets" - The lead says they are paper targets.  Needs to be reconciled.
Whoops, updated the body when I read that source but not the lead. Fixed. --PresN 17:18, 26 January 2016 (UTC)
"At the end of the spot's trajectory, the beam defocuses if it is within the bounds of a target, resulting in the spot expanding and blurring" -  The beam always defocuses right?  The goal is to arrive at the target just as the beam defocuses to score a hit.
Oof. Fixed; split it into two sentences- what happens and what the goal is. --PresN 17:18, 26 January 2016 (UTC)


### History
"as it used purely analog hardware rather than running on a computing device" - There are such things as analog computers, so "analog hardware" and "computing device" are not mutually exclusive terms.
Now 'and' instead of 'rather than'. --PresN 17:18, 26 January 2016 (UTC)
A few more concerns than the last couple of articles, but still nothing that cannot be remedied in short order.  Therefore, I will place this review  On hold until changes are made. Indrian (talk) 17:15, 23 January 2016 (UTC)

@Indrian: Not as good as some of the other articles, but fixed up now. I've responded inline to all your concerns. --PresN 17:18, 26 January 2016 (UTC)
@PresN: Everything looks good now.  Thanks for bringing so many early video game articles to GA status!  Indrian (talk) 18:39, 26 January 2016 (UTC)
Oh, by the way, I promoted, but I am going to wait to add it to the list on the GA page until after the move. Indrian (talk) 18:51, 26 January 2016 (UTC)
@Indrian: Now done. --PresN 18:58, 26 January 2016 (UTC)

First off let me say that I have no idea what I am looking at.  I am trying to post a what appears to be a glaring issue with the article, but all I see in this edit window is tags and flags, where do I edit the content?  Second of all the article says that this was the first interactive electronic game, how can this be true with arcade games like Seeburg's Ray-O-Lite taking earlier positions in pre-videogame history?  And that's just games that are products, technically the first real interactive electronic game was probably a game of chicken played with an electric catfish. — Preceding unsigned comment added by 50.53.119.205 (talk) 03:54, 25 March 2020 (UTC)

Well, there's a difference between a game that uses electricity and an "electronic game", though, the article could define that better. There is a difference between this and the Seeburg Ray-O-Lite and prior electric games- I used the phrase "the first interactive electronic game" because that's what sources use, but the Ray-O-Lite is on the edge as "electronic" as it used a vacuum tube as a light sensor, though it didn't use it as "electronics" as the term is defined (amplification/modification of an electrical signal) but just as an on/off resistor. That's splitting hairs a bit, though. I've changed the text to specify that this is the first known game to use electronics and have an electronic display, though some prior games like the Ray-O-Lite may use "electronic" components in some fashion. Where the line moves from "electro-mechanical games" to "electronic games" is fuzzier than the line between electronic games and "video games", though that's a bit fuzzy too. --PresN 05:15, 25 March 2020 (UTC)

There appears to be much divided opinion as to whether this contraption is a video game, with one user insisting that it is not and several users insisting that it is.
Well: we can certainly all agree that it is a game as ‘amusement device’ is precisely what a game is. We should be able to agree that it is an electronic game as it contains eight electronic vacuum tubes and one electronic cathode ray tube (I would assume that the power supply would contain at least one further vacuum tube as a rectifier).
The question is: is this a ‘video game’? It would rather depend on how you define ‘video game’, or more to the point, how you define ‘video’. These days, one might consider a video game as a console of some sort that produces a television signal (video) that you then connect to a television set or monitor. The television signal is the video part. However: video is a much broader concept and the word video and in particular video signals existed before the term was applied to television signals with the introduction of ‘video recording’ (prior to this the visual part of a television broadcast was known as the ‘vision signal’. Video recording as a concept existed right from when television was invented even though the term itself was yet to appear (John Logic Baird recorded his 30 line televisor (an early television) signals on 80rpm gramophone records in 1926).
The word video was originally the demodulated signal in any radar receiver. The is was usually, but not necessarily, the signal used to provide the radar display on a cathode ray tube. It also was applied to the output from (say) a Döppler radar where there was no intention of displaying the signal in any form. The television world adopted it as a name for the ‘video recorder’ - because it was a recording of a signal intended for display on a CRT. As technology has developed, the word video has been expanded to apply to any signal intended to be displayed on an electronic display device. Modern usage now, incorrectly, calls the medium containing a television recording as ‘a video’ (in reality probably a lazy abbreviation of ‘video recording’).
The arcade game ‘Asteroids’ is universally accepted as a video game (indeed the Wikipedia article on the game is entitled “Asteroids (video game)”). But asteroids did not generate, use or display a television type signal in any form. Asteroids was a vector scan system. The signal that was displayed on the CRT is a video signal in that it is a signal intended to be displayed on an electronic display device (the CRT). 
If asteroids is a video game, then so is the cathode-ray tube amusement device which is also a vector scan system in exactly the same way as asteroids. It would not have received this accolade at the time it was invented as the term ‘video’ had not been coined. That it was never put into production is immaterial. The prototype, at least, would have had to exist otherwise it could not have been patented (you have to physically be able present an invention when you patent it). I might have assumed that this was actually made by modifying a cathode-ray oscilloscope if it were not for some strange design elements. The X and Y centring controls are ganged which is odd (though may be a draghting error). Also the deflection drivers are capable of far more power than is required as electrostatic deflection requires no current (maybe they used what parts were to hand?). 
I note: that there was some controversy over whether a video game should contain digital computing elements. There is no requirement at all. Early radar receivers produced a video signal without any computational complexities whatsoever. The subject device does feature computational complexity (if complexity is the right word!) as it is has a very (very!) simple analogue computer circuit capable of solving simple integral parametric equations (essential for working out the trajectory of artillery shells, though it does not appear to account for the shells slowing in flight). Some of the knobs adjust the parameters of these equations. Vuehalloo (talk) 13:19, 30 October 2021 (UTC)

@Vuehalloo: (and @81.157.153.208, 99.165.35.182,  and Wtshymanski:, though I don't think IP addresses get pings): So, despite how the "several users" (who all showed up the same week to a low-traffic article to argue the same point) are focusing on the sentence in the lede, the lede summarizes the article body. The part of the body being summarized is:
"Despite being a game that used a graphical display, the cathode-ray tube amusement device is generally not considered under most definitions to be a candidate for the first video game, as it used purely analog hardware and did not run on a computing device; some loose definitions may still consider it a video game, but it is still usually disqualified as the device was never manufactured.[3][4][10][11]"
Those four references are to:
Blitz, Matt (March 28, 2016). "The Unlikely Story of the First Video Game". Popular Mechanics. "While Goldsmith's game idea was certainly ahead of its time, Alex Magoun, a historian at the Institute of Electrical and Electronics Engineers, notes that the device was not what we would consider much of a video game today. "There's no computer, no microprocessor generating random airplane paths.They are just sticking targets on the picture tube and then using a couple of electromechanical controls to try to guide an electron beam. In that respect, it is not a fully developed technology by any means.""
Smith, Alexander (November 27, 2019). They Create Worlds: The Story of the People and Companies That Shaped the Video Game Industry. 1: 1971 – 1982. pp. 140–141. CRC Press. ISBN 978-1-138-38990-8. "Some have been tempted to label the "cathode-ray tube amusement device" as the first video game, but the device fits no definition of the term. There is no video signal, no computer, no software program, and only the simplest of electronics. There are also no graphics beyond the arc of the missle, as the targets for the system consisted of physical objects affixed to a screen. Basically, the same effect could have been created by mechanically controlling a flashlight shining its beam on a piece of paper."
Kowert, Rachel; Quandt, Thorsten (August 27, 2015). The Video Game Debate: Unravelling the Physical, Social, and Psychological Effects of Video Games. pg. 3. Routledge. ISBN 978-1-138-83163-6. "Another argument for the earliest origin of the video game can be based on a patent for a "Cathode Ray Tube Amusement Device" filed in 1947 and issued in 1948. [...] While sharing some visual display traits with Higinbotham's Tennis for Two game, Goldsmith and Mann's device was completely mechanical and used no computer program or memory. There is therefore a good case for Tennis for Two as the first video game prototype because earlier putative "first" video games lacked either a graphical motion display (e.g., Nim, OXO) or computing technology (e.g., the Cathode Ray Tube Amusement Device)."
Wolf, Mark J. P. (August 16, 2012). Encyclopedia of Video Games: The Culture, Technology, and Art of Gaming, Volume 1. Greenwood Publishing Group. pg. 218. ISBN 978-0-313-37936-9. "[...] U.S. patent #2,455,992 for a "Cathode-Ray Tube Amusement Device from 1948. The device described did not get beyond the prototyping stage, nor did it produce a video signal, which, by a strict definition, would have denied it status as a video game, even if it had gone to market."
Against these 3 books and an IEEE historian, the "several users" have offered... absolutely nothing. You just insist that it's "obviously" a video game. If you have actual sources beyond your own personal opinion stating that the CTRAD is definitely 100% considered a video game then please, share them, because as it stands "the cathode-ray tube amusement device is generally not considered under most definitions to be a candidate for the first video game" seems to be a reasonably fair summary of the literature. --PresN 00:30, 31 October 2021 (UTC)
User often show up at the same time because either they are watching the article or because they follow editing patterns.
Not one of your four references supports the assertion that the cathode-ray amusement device is not a video game. They are opinionated original research that has the added problem that they are all technically inaccurate in many ways and thus are not reliable sources.
First reference: states tat the cathode-ray tube amusement device is a video game - specifically, “… not much of a video game today” but a video game nonetheless. What was he expecting for 1947: high resolution colour graphics? This reference does not support the claim.
Second reference: Claims, “… there is no video signal, no computer, no software program …”. First point - wrong. There is a video signal and the four 6V6s are the video amplifiers supplying the twin channel video signal to the CRT’s deflection plates. Second point - also wrong. The four 6Q5s (I assume they are all 6Q5s the circuit does not specify otherwise) form an analogue computer which calculates the trajectory of the shell. Analogue computers do not have software programs (nor memory), they don’t work that way. This reference is not a reliable source because the author clearly does not understand the technology that he is describing. He is also another author who seems to be expecting high resolution colour graphics from 1947 technology.
Third reference: States, “While sharing some visual traits with Higinbotham’s Tennis for Two game the [CRT amusement device] was completely mechanical and used no computer program or memory. There is therefore a good case for Tennis for Two as the first video game prototype …”. Again: the author completely has no idea what he is on about and must be completely unaware of how the CRT amusement device worked or what it was. First point: the CRT amusement device was not mechanical, as he claims, in any shape or form. It was resolutely electronic.
But the main problem as a reference is the author accepts that Tennis for Two was a video game. Tennis for Two is technologically identical to the the CRT amusement device. Both used analogue computing that by definition has no program or memory. Both calculated the trajectory of objects by solving integral parametric equations (Tennis for Two had the complication of a net and bats, but the underlying technology was identical). (Artillery shells or tennis balls - exactly the same parametric equations.) Both were video systems in that they provided a vector scan video signal for the CRT to display in exactly the same way (in the latter case built into a real oscilloscope).
Fourth reference: Claims,”The [CRT amusement device] did not get beyond the prototyping stage, nor did it produce a video signal, which, (sic) by strict definition, would have denied it status as a video game …”. Tennis for Two is widely accepted as a video game even though it only ever existed as a laboratory curiosity to publicly demonstrate an analogue computer. It was never produced commercially. And it did produce a video signal as outlined above. There is no evidence as to where this ‘strict definition’ came from.
I notice that the claim, “Under most definitions, the device is not considered a [[video game]”. Has been reinserted into the article, but this is just a weasel phrase. No evidence has been provided that any reliable definition disqualifies it, let alone ‘most’. Even the four references cited above fail to support the claim in the worst possible way.
The article video game’s topic sentence would cover the CRT amusement device and even offers Tennis for Two as an example of an early video game. As stated above, the two are technologically identical. Thus if the latter is a video game then so is the former.
The Tennis for Two attempts to disqualify the CRT amusement device claiming that it did not, “… run on a computing device”. It may not have run on a separate computing device but it did contain a computing device within, so the claim that Tennis for Two was first is incorrect.  Also claimed in this article, “Tennis for Two … contained no technological development to separate it from earlier games … the earliest known computer game with visuals created purely for entertainment purposes”. So, that claim states that it is technologically identical to the earlier device (in that it had nothing new). But it wasn’t the earliest known game as the CRT amusement device also had a visual display and was created solely for entertainment (as the name says). Tennis for Two was eleven years behind the times. Vuehalloo (talk) 10:40, 31 October 2021 (UTC)
@Vuehalloo: If you have actual sources beyond your own personal opinion stating that the CTRAD is definitely 100% considered a video game then please, share them. "I disagree with this published research" is not a source. --PresN 12:42, 31 October 2021 (UTC)
It’s not a question of disagreeing with this published research. It is the fact that it is original research based on technically inaccurate information. It is also that none of it supports the premise that the device is not a video game - indeed, much of it supports the view that it *is* a video game. So far nothing valid has been offered that any definition, let alone most, definitions exclude it from being a video game. Most rely on either it doesn’t produce a video signal or that there is no computational ability, neither of which applies here.
So far, you are the sole contributor pushing the notion that it is not a video game to the point of offering up dodgy references based on false information that don’t even support the idea. You are the one claiming that is not a video game when it so clearly is and have even offered sources confirming it. You are the one who must provide sources for your odd claim. Vuehalloo (talk) 13:11, 31 October 2021 (UTC)
No, it would be WP:Original Research if I was the one stating my opinion based off of no sources but only my own logic. Someone writing and getting published a 500+ page research book on the history of the video game industry is just called "research", and citing multiple published sources for a statement is called literally what we're supposed to be doing here as editors. Again, if you have actual sources beyond your own personal opinion stating that the CTRAD is definitely 100% considered a video game then please, share them. "I disagree with this published research" is not a source. --PresN 13:19, 31 October 2021 (UTC)
Repeating yourself does not make your claims any more correct. You cited material is wholly unreliable because it is technically wrong on every level as has been explained clearly above.
And I have just noticed that this article is listed as a “Video game good article”; is part of the “Early history of video games” and is within the scope of “WikiProject video games”. So clearly I, and the three other users with whom I agree, are not alone in this. Vuehalloo (talk) 13:27, 31 October 2021 (UTC)
Look, I'm not sure how to be more clear here. Please read Wikipedia:Citing sources or WP:VERIFY. We cannot write "CRTAD is definitely a video game.<ref>Some person named Vuehalloo said so, and they seemed like they knew what they were talking about so you should trust them more than any published reputable sources.</ref> We need actual sources, and since we already have several books saying otherwise, and it doesn't matter that "some person named Vuehalloo" disagrees with them, we're going to need multiple actual, reliable sources to show that rather than "it's not usually considered a video game, though some sources think it is" it's "most sources think it's a video game, but a few sources don't". I'm repeating myself because it doesn't stop being true just because you don't like it: if you have actual sources beyond your own personal opinion stating that the CTRAD is definitely 100% considered a video game then please, share them. "I disagree with this published research" is not a source. --PresN 15:00, 31 October 2021 (UTC)
Well reading Vuehaloo's analysis of what your sources actually say, they don't 'say otherwise' at all. None of them appear to support the contention that the CTRAD is not an amusement device. One specifically says that it is, and the other states that an otherwise identical device, the Tennis for Two game, is a video game and therefore the CTRAD must be. 81.157.153.208 (talk) 16:05, 31 October 2021 (UTC)

Since everyone is obsessed with the notion of how a video game is defined and making rash (and unreferenced) claims about the proportion of definitions which include or exclude the cathode-ray tube amusement device (CRTAD), I though I would try to find some definitions.
Let's start with dictionary sources.
Oxford English Dictionary:- 
a game in which you press buttons to control and move images on a screen 
Hmm! Not very helpful. Would exclude almost every game in existence.
Oxford Language Dictionary:-
a game played by electronically manipulating images produced by a computer program on a monitor or other display.
The only definition that I found to specify a computer program. But analog computers are programmed by physically plugging the circuits together to produce the required mathematical function, so the CRTAD fits.
Cambridge English Dictionary (Oxford Advanced American Dictionary had the identical definition):-
a game in which the player controls moving pictures on a screen by pressing buttons
Practically a rewrite from the Oxford English Dictionary.
The COBUILD Advanced English Dictionary:-
A video game is a computer game that you play by using controls or buttons to move images on a screen.
CRTAD certainly fits in this definition. It has a screen and controls plus a button.
Collins English Dictionary:-
any of various electronic games that are played by manipulating an input device in response to the graphics on a screen
CRTAD fits here too. It has graphics on a screen and input devices.
Crossing the pond and looking for American English sources: Penguin Random House Dictionary:-
any of various games in which players respond to actions displayed on a computer screen
Again fits. the CRTAD has a computer screen as it is a screen driven from an analog computer.
Websters New World College Dictionary:-
any of various games involving images, controlled by players, on a cathode-ray tube or other electronic screen
Again it covers the CRTAD as images, player and cathode-ray tube are all present.
Wikipedia's own definition at Video game which seems to have been plagiarised to multiple other sources:-
A video game or computer game is an electronic game that involves interaction with a user interface or input device – such as a joystick, controller, keyboard, or motion sensing device – to generate visual feedback.
Yup! all there. Gives an alternate name of computer game, but CRTAD contains a computer.
Cambridge Academic Content Dictionary (essentially an American English publication)
a game in which the player controls moving pictures on a television screen by pressing buttons or moving a short handle:
The first definition found that specifically states a television screen (implying a raster scan video signal). CRTAD does not feature such a device, but the definition might have been written around modern day video games where a television type signal is the norm. Raster scan television video is a specific type of video signal.
Your Dictionary (here readers vote as to their preferred definition - probably as reliable as Wikipedia isn't)
Most votes An electronic game played by manipulating moving figures on a display screen, often designed for play on a special gaming console rather than a personal computer.
CRTAD fits in all criteria. (Interestingly a definition mentioning software and television screen has (so far) received no votes).
I tried to find some more academic work and dug up this from the University of Technology of Compiegne in France. It offered
A videogame is a game which we play thanks to an audiovisual apparatus and which can be based on a story.
CRTAD certainly fits in this definition. It is not based on a story but that is not compulsory by this definition. Searching revealed that this definition has been adopted by the Digital Games Research Association (DiGRA). The above university presented it in a paper at a DiGRA conference in 2005 where it was formally adopted.
This interesting sentence cropped up in a PhD thesis entitled, "Basic approaches to the definition of the concept of "videogame" as an element of modern scientific discourse" from Kiev University in 2018:-
[Discussing video games in the social and individual life of a person]. It is emphasised that despite the active penetration of videogames into the life of a person, a general definition of a "videogame" has not yet been formed in scientific discourse that would comprehensively cover this phenomenon.
It is clear that there are precious few definitions that exclude the CTRAD. The claim 'most definitions' exclude it is unreferenced and pure speculation. The others certainly are technically incorrect and therefore by definition are unreliable. 81.157.153.208 (talk) 16:00, 31 October 2021 (UTC)

It seems the problem here is the difference between the technical and layman definitions of terms, and that nobody is actually incorrect here.  A “video signal” is certainly generated, as how else is the CRT going to put objects on the screen, but Ralph Baer and the U.S. Court system and other actors looking into the origins of all this focused on a video signal as a generator of a rasterized image, which yes, is not a requirement for a signal to be video, but informed how the term has been understood in the context of video games.  And sure, if there are calculations being done by the hardware, it can be considered an analog computing device, and other early games like Tennis for Two also use analog computing devices as part of their makeup, but digital computation is also seen as a component of video games for most people examining the subject.  So yes, those books, which were written by historians and not engineers, do probably overreach by using too broad a language when they should have gone more specific.  You can correct me if I’m wrong, but I don’t think they would get in trouble if they had said “no rasterized images generated by a video signal” and “no digital computing hardware” instead of the broader “no video signal” and “no computer.”  So yes, I think you are technically correct (some would call that the best kind of correct). But at the end of the day, the question is not just what defines a video game technologically, but what are the complete set of characteristics that truly define a video game?  That is where the policy on verifiability, not truth comes in.  If scholars decide something is not a video game, then that is what we cite to here.  Flubbing a little of the technical minutiae does not change the fact that many discount CTRAD due to a lack of rasterization or digital computing or too much reliance on electro-mechanical components or a host of other reasons in some combination.  It does not make the sources generally unreliable, just slightly off on the technical explanations.  If later scholars, who may indeed appreciate the technical nuances more,decide a basic signal and analog calculations are enough, the article will be changed to reflect that.  Just because YOU think it’s enough, however, does not make it so.  Get published in a journal, and then we can talk. Indrian (talk) 17:00, 31 October 2021 (UTC)
Just to kind of hit on this another way, I think the current consensus is that CTRAD and Computer Quiz and the Nimatron, and a few other devices are all edge cases that exist in a strange realm between electro-mechanical games and video games. CTRAD at least has a CRT unlike some of those others, but incorporating a CRT is not in itself a perquisite for being a video game, as the definition usually includes all manner of computer games these days, including some that were never played on a CRT or on an electronic display of any kind.  So the question becomes how electronic does a game need to be before it qualifies as a video game?  At this juncture, scholars have ruled that this one does not quite make it. That may change six months from now or sixty years from now. The funny thing about history is it continually changes way more than you would expect for stuff that has already happened. Indrian (talk) 17:24, 31 October 2021 (UTC)
I have looked into this device in a bit more detail because I was somewhat alarmed at PresN’s claim in an edit summary, “It oscillates the spot in the Y while increasing it steadily in the X which makes a parabola.” The circuit certainly contains no oscillator, so this statement appears to be part of a snow job to support the notion that this is not a video game come hell or high water.
I looked once again at the circuit. I also looked online for any information as to how this thing actually worked. There wasn’t much and some of it was somewhat confusing and contradictory. What I gleaned was that the device plots a parabolic arc whose angle to the horizontal is determined by the player, and it ‘explodes’ after an interval determined by the player. The aim is to get the shell to explode right where the target is stuck to the tube face.
The tube at the top left of the circuit appeared to be wired as an integrator (due to what appeared to be an integrating capacitor connected between the anode and cathode plus a reset switch grounding the cathode and one end of the capacitor). But then I realised that if it had an output, it lacked any input. And then I spotted the dot inside the tube’s circuit symbol. The 6Q5 looked like a thyratron, and I then found the data sheet that confirmed it. Thus the 6Q5 is a standard single shot saw tooth generator. Switch 5 is the push button that starts it, launching the shell.
So where does the parabola come from? That was the problem. The saw tooth feeds the two cross connected resistors which in turn drives the four 6V6 deflection amplifiers (why did they use power beam pentodes when the deflection plates consume no power?). But with a saw tooth source signal all you will ever get is a dead straight diagonal line. What was apparent is that tube 44, at some point, switches a relay which causes the beam to defocus, presumably simulating the shell exploding.
It took some hunting, but I eventually found the text of the patent (especially as the cited link in the article is broken), and as you read through it, the answer is revealed. I (and possibly others) assumed that the CRT was a an oscilloscope tube (especially as the article mentioned this).
The tube is not an oscilloscope tube and would be all but useless for such an application. It a special type of tube where the X deflection plates are made of a non conducting material but coated with a high resistance coating (These are actually resistors 21’ and 31’ in fig 1). The output from the X deflection amplifier is connected to the ends of the deflection plates nearest the screen whereas the end closest to the electron gun are connected to the 400 volt supply. This means that there is zero deflection as the beam enters the influence of the plates (because they are at the same potential), but the deflection increases as the beam traverses the plates. This causes the traced path to curve into a parabola like shape (though, as fig 4 shows the path will not return to the ground and the patent does not claim that the path is a parabola anyway).
Variable resistors 11 and 12 determine the path that the shell follows, and variable resistor 41 determines the point at which the shell ‘explodes’.
For what purpose was such a tube originally constructed? I haven’t got a clue and so far, I have been unable to find any references or data sheets for such a tube.
What is curious is: why they bothered to go to the expense of patenting the device. It was obviously never going to be produced as even oscilloscope tubes were extremely expensive in 1947. But as this uses a specialist tube likely to produced in even smaller quantities, no one was ever likely to be able to afford it.
I would submit that a simplified description of the operation of this video game would make a good addition to the article. Vuehalloo (talk) 16:24, 1 November 2021 (UTC)
So, a few points:
Your analysis is very interesting! I called it an oscilloscope because that's what sources called it (currently: "basic oscilloscope type circuitry", which is closer but sounds like still wrong); I'll recheck the patent to see if there's a clear way to describe it to non-engineers, since what's there now is evidently misleading. Sounds like "parabola" is wrong too. I expect they patented it because DuMont told them to- sources note that it's not clear why they were working on this in the first place, but it seems likely that DuMont was looking for commercial products and decided to patent whatever they came up with even if it wasn't commercially viable. That's just a guess, of course, so it can't go in the article.
You said the patent link is broken for you; it redirects to [1] for me and works fine? Espace is European while I'm in the US, so I'm surprised the link isn't working for you- or is the citation taking you somewhere else?
I wasn't trying to do a "snow job", I was objecting to what y'all have put in right now, which claims that the circuitry "calculat[es] the trajectory of shells" and that it is "analog computing circuitry" that "perform[s] very simple mathematical functions including integration", which is a) ludicrous, it "calculates" exactly nothing as you note- it's got variable resistors directing an electron beam and b) nonsensical even if it did calculations, since "integration" has nothing to do with calculating the arc of a parabola- or just making an curved arc, as you note.
This is all very interesting, and it seems true as far as my dusty EE degree shows; if you're able to find any reliable source that analyses the schematics like this I'd love to cite it. We can't, of course, cite this post because, not to belabor the point again, Wikipedia summarizes what is verifiable in reliable sources, not what is "true", which does get frustrating in more obscure areas where you can't find sources to back up what is "true". --PresN 20:21, 1 November 2021 (UTC)
It’s not really my analysis. I was just paraphrasing the patent. The circuit is obviously (very) basic oscilloscope circuitry and (from the patent) is supplying a video signal (in the form of two linearly changing deflection signals). There is clearly no computational capability whatsoever (other than to solve the equation y=x - which can hardly be described as requiring computational ability). The magic happens in the CRT because (again from the patent) the curved paths of the shell are from a deflection system deliberately designed to be non linear. This basic premise can be included in the article because it is what the patent states.
It is not uncommon for companies to patent everything and anything just in case an opportunity presents itself to make some money.
The patent link is broken for me. All I get is an Espacenet logo and a constant line from left to right underneath it.
The Statement that the circuit was integrating some function was not unreasonable as this would be the method of generating a parabola using analog circuitry if the CRT was an entirely linear device (In this case it would simply integrate the linear changing X signal which would equate to the slope of the parabola - exactly what integration does.). The vacuum tube top left of the circuit, had it not been a thyratron, would make a viable, if unusual, integrator even though the tube is configured in a common grid mode. But as I said, I hadn’t twigged the dot in the circuit symbol or that it had nothing to integrate.
I note your statement that Wikipedia requires what is verifiable in reliable sources. Your continued reinsertion of, “Under most definitions, the device in not considered a video game”. In this case: that ‘most’ definitions exclude it is not referenced or proven in any way. This cannot be claimed. I had a hunt around for sources of definitions of video games and even sources on video game history. A number of definitions did require some computing ability but a number made no mention. It was roughly half and half (erring a little on the side of definitions requiring it though I only checked a limited sample so that cannot support ‘most’). It would be necessary to examine *every* definition (which one would have to do to prove the ‘most’ claim if it could not otherwise be supported by a reliable source for the claim).
I think it would be better to change ‘most’ into ‘many’ which which would be less controversial.
We can certainly now claim that the CRTAD had no effect or influence on future video games because, as far as can be ascertained, nobody produced a game that relied on a non linear CRT to produce the required graphics. Further, the CRTAD was never manufactured (indeed may sources state that the device was unknown until 2001 or 2002 - sources vary). Vuehalloo (talk) 18:36, 2 November 2021 (UTC)
Changing most to many sounds very reasonable. Done. --PresN 21:03, 2 November 2021 (UTC)

@PresN:Following, some recent dubious editing and past good faith editing, I noticed that the article contradicted itself by stating that there was no computational circuitry (which we now know to be correct) but also stated that the device contained integrating circuitry (recently added I believe). I have removed any reference to analogue integrating circuitry.
Interestingly: I could not visualise how the arced shell paths were produced, so I used some CRT modelling software to reproduce the characteristics. Using oscilloscope tube parameters, I was able to modify the horizontal deflection to add the complication of the resistive deflection plates.  But it totally failed to produce any curved paths (not even slightly curved). All it succeeded in doing was to reduce the horizontal deflection sensitivity by about a third. I therefore have to admit that I may well be missing something. Either that or the patent is.
The one thing it did predict (and I had already realised that it was going to do it) was that the spot on the screen would not be a spot but a short vertical line. This is because in fig 1, the final anode is at earth potential where as the Y deflection plates are at around 200 volts. The final anode must be at the same potential as the Y plates to get a circular spot. Of course, the figure does not form part of the patent, serving only to clarify the text. The text itself does not mention the final anode, so it is quite possible that it was really connected to a positive voltage supply (this would usually be through a potentiometer labelled ‘astigmatism’). Vuehalloo (talk) 14:31, 4 November 2021 (UTC)