User talk:Interferometrist/Archive01

Welcome!

Hello, Interferometrist, and welcome to Wikipedia! Thank you for your contributions. I hope you like the place and decide to stay. Here are some pages that you might find helpful:

The five pillars of Wikipedia
Tutorial
How to edit a page and How to develop articles
How to create your first article (using the Article Wizard if you wish)
Manual of Style

I hope you enjoy editing here and being a Wikipedian! Please sign your messages on discussion pages using four tildes (~~~~); this will automatically insert your username and the date. If you need help, check out Wikipedia:Questions, ask me on my talk page, or ask your question on this page and then place {{helpme}} before the question. Again, welcome! Steve Quinn (formerly Ti-30X) (talk) 04:38, 1 March 2010 (UTC)[reply]

Welcoming committee

Here is page for new editors at Wikipedia: Welcome to Wikipedia. ---- Steve Quinn (formerly Ti-30X) (talk) 04:38, 1 March 2010 (UTC)[reply]

Writing text

First, the reason why your insertions

   come out in long lines like this

is because the first letter of a paragraph of text, for some reason, has to start up against the left-most boundary. In other words, if the paragraph is indented, it comes out in a long line (like it did above). It seems to be how the software is set up. If you notice the paragraph formatting in Wikipedia articles are "block" paragraphs. You may find one here or there that isn't, but it is rare. (I have only seen one).

The way to indent your text,

is to use at least one colon ":" before the start of a sentence or statement.

The more colons use you use

then the more pronouced is the indent. In other words, the colon is the first character of an indented sentence or statement.

With no colon at the beginning of the statement, the text returns to normal, like this. Also, a colon is just punctuation if it is not used as the first character of a senetence.Steve Quinn (formerly Ti-30X) (talk) 22:37, 2 April 2010 (UTC)[reply]

Lecture notes

Right now I am looking into your question regarding notes that you transcribed from a course or a professor. I am assuming that you want to write your notes into an article on Wikipedia. There is no problem with that as long as you can support these with reliable secondary and tertiary, sources. What I mean is, try to back up your material from peer reviewed articles, books written by experts and researchers in the field, and acceptable news sources. Primary sources are acceptable, too, but it depends on the context of use and these are probably best backed up by secondary sources as well. Here are some guidlnes you can look at WP:RS, WP:PSTS, and WP:SOURCES. ----Steve Quinn (formerly Ti-30X) (talk) 22:37, 2 April 2010 (UTC)[reply]

Re: Frequency control of He-Ne laser

Thanks for your reply. A bit of background to my question, I'm part of an Amateur radio group who have become a little bored with the usual radio frequency stuff so we want to try communicating with light beams.

Your idea of mounting the mirror on a piezo beeper is a good one but as you noted it's far from optimal for an audio frequency signal. But the issue has since become moot as the group has decided to go with diodes. They are massively cheaper, smoking a few won't bankrupt the project - trashing a gas laser is much less amusing.

The idea we have settled on is to pulse the diode at a "carrier frequency" rate, we're going to try for ~100MHz if we can find a diode that can switch fast enough - though a recent idea is not to switch it completely on and off but to go dim/bright instead as that will allow a much faster pulse rate than switching. Then the audio signal will modulate the pulsing - the analog working group will work on directly shifting the pulse frequency (FM), while the digital group (which I am now part of) will use pulse width modulation in a binary format - long and short pulses to represent 1 and 0 as is done in CD/DVD drives. The digital group will be using the common WAV codec to start with but some of us are ambitious enough to try to transmit in MP3 format. We're starting with across the table range but would eventually like to extend it as far as possible - by even reflecting the beam off clouds to exceed direct line of sight. The receiver will use a photodiode, its complexity is in the software used to extract the signal rather than in the mechanics - a photodiode is a fairly simple "dumb" device. The eventual "product" we're aiming for is a tranceiver that fits on a telescope eyepiece and connects to a computer through either USB or WiFi. Roger (talk) 07:22, 19 October 2010 (UTC)[reply]

ABX test

If you have any statistics maths background, can you take a look at the ABX test page? An IP editor is changing some numbers away from what I have in a QSC Audio user manual, to numbers that have no apparent verifiable origin. If those numbers are right, or can be supported, I am willing to concede that QSC made a mistake. Binksternet (talk) 14:58, 13 April 2011 (UTC)[reply]

Sure, I'll look at anything technical ;-) but have no idea what ABX means and probably will never use it again.... Interferometrist (talk) 15:04, 13 April 2011 (UTC)[reply]

Yeah, this is just the sort of stuff I like! But usually when I do a problem with binomial distributions I use the approximation based on normal distributions, but in this case you really need to use the exact binomial distribution.... I'm only saying that because I need to write a little program (don't worry, it goes into my library and WILL be used again!) and should have your answer in a little while. Of course whichever of you is right won't get a published reference out of this, but at least you'll know whether you're justified in reverting. Interferometrist (talk) 15:20, 13 April 2011 (UTC)[reply]

Well I hate to break it to you, but the numbers in the new edit are correct. That just goes to show you (not surprisingly) that industry (I don't know who QSC Audio is) often gets technical matters wrong especially when it is in their interests, and especially when it is something the average customer isn't going to (or simply cannot) check out themselves. In fact I sort of wanted to say the same thing amount antenna measurements in the antenna articles, but that's where actually measurements are even more difficult (as well as theoretical predictions) so it will be hard to find reliable sources where someone has gone out to disprove the spec sheet that came with their antenna, though I'm sure that many (if not most!) companies either intentionally or (more likely) subconsciously tilt the figures in their favor. But you already knew that ;-)

Interferometrist (talk) 15:42, 13 April 2011 (UTC)[reply]

I should also point out that the wording (which he removed):

a minimum of ten listening trials in each round of tests, as this allows a 95% level of confidence in results

is technically incorrect, (although the sentence may have been correct, that they said so). It's possible to get a significant result with as few as 5 trials if they are all successful (only would happen 1/32 of the time if the null hypothesis were true) but the more trials you have the more sensitive the test is (lower probability of a type II error). So I guess the new edit was right on both scores, even if it was from one of those often unreliable IP users! (Tell him to get an ID!) Interferometrist (talk) 15:51, 13 April 2011 (UTC)[reply]

I guess I DO remember this now, but had just called it an A-B test, and often wasn't a test at all but a way of selling speakers to someone by proving to him that he could hear the same improvement as the salesperson could, I mean unless there was something wrong with him ;-) Interferometrist (talk) 16:01, 13 April 2011 (UTC)[reply]

QSC is known for making robust power amplifiers suitable for large-scale sound reinforcement. They made the ABX test product for a couple of years but few were sold—I think they used it internally to sell amplifiers, by comparing the customers' favorites with a comparable QSC product. I do not see how they would have benefited from the published binomial distribution being wrong. By following the QSC numbers, people using the ABX test gear would have conducted more trials than strictly necessary for 95% certainty, and whatever results they were getting would be more certain. This could hardly hurt them or help them! It would simply strengthen the results, and if those results were trending toward a non-QSC amplifier, this trend would be more powerful.

Anyway, thanks for kicking this little problem around. I majored in music because math was not my favorite thing (even though my SAT tests at age 17 showed perfectly identical math and English skills, both high enough to get me a four-year scholarship!) Cheers – Binksternet (talk) 16:03, 13 April 2011 (UTC)[reply]

I'll bet the reason they got the wrong numbers is that they do what I almost always do (since I deal with larger numbers of trials) and use the approximation based on the normal distribution which is valid when N>100. Someone there should have been more careful/smart though.

The main problem with such a test having rather few trials is that it isn't good at showing the opposite, that there is NO difference between A and B. In fact you can never really show that, you could only show that the difference isn't as great as someone might be claiming and then you need a more specific claim (such as "people can hear the improvement at least 80% of the time") and can set a criterion using that. Also, 95% is called "significant" but that term can still be misused. For instance, if 3 people from a company came to listen to speakers I could give them each a test and if one of them succeeded say "Look, HE can hear the difference!" Now performing THAT test (looking at the 3 as a single test, which they are in this case) doesn't have 95% confidence, only about 85%. Or if I'm selling something ridiculous to a lot of potential customers I might be perfectly happy if only 1 in 20 of them buy something I'm advertising after the other 19 flunk the test. (Especially if each sale netted a huge sum!). I will add a little wording to the article though. Interferometrist (talk) 16:22, 13 April 2011 (UTC)[reply]

Oops! I must have holding the laptop upside down... Looks like QSC's proffered numbers recommended fewer trials than are necessary for 95% confidence in one person's single trial run. That makes their version somewhat less confidence-inspiring, but it still does not change whether their product fares well or poorly in tests. Binksternet (talk) 17:28, 13 April 2011 (UTC)[reply]

Wrongful deletion of Citation Needed tags.

This item has been placed on the administrator's noticeboard here.

Also reported is the abuse of article protection to prevent editors from challenging your rubbish. 86.183.175.94 (talk) 17:33, 21 April 2011 (UTC)[reply]

Edit warring

Hello! Just a mention, an IP user you seem to have had some trouble with earlier has filed a report about you on WP:3RRNB. I think it's only fair that you know, especially since you haven't been given the mandatory courtesies (warnings etc) before the noticeboard report. Zakhalesh (talk) 17:35, 21 April 2011 (UTC)[reply]

Ah, I failed to see the notice given to you a few minutes before I posted this. Zakhalesh (talk) 17:39, 21 April 2011 (UTC)[reply]