Jump to content

Wikipedia:Featured picture candidates/Amplitude modulation vs. frequency modulation

From Wikipedia, the free encyclopedia
An audio signal (top) may be carried by an AM or FM radio wave. - original caption
Reason
A simple, concise illustration of the difference between AM and FM modulation.
Proposed caption
The signal to be modulated (top) is shown as represented by amplitude modulation and frequency modulation.
Articles this image appears in
Amplitude modulation, Frequency modulation, Modulation
Creator
User:Cuddlyable3
  • question I would like to see those suggestions below implemented. Also, the leftmost edge of the FM waveform never moves - would there actually be a fixed point there, or is that a mis rendering? Debivort 04:30, 5 September 2007 (UTC)[reply]
It's not a mis rendering but is typical of what one sees on an oscilloscope whose sweep has to be triggered by an edge of a waveform, so that edge appears stationary. Any of the 3 waves could have been used as the trigger.Cuddlyable3 16:13, 5 September 2007 (UTC)[reply]
  • Oppose - The modulated signals are off by 180 degrees (i.e. its backwards). The peak of the signal wave should corrospond to the highest amplitude of the AM signal and highest frequency of the FM signal. I think that the lines could be smoothed out quite a bit. It would also be much easier to understand if the carrier frequency was higher and the signal was irregular as opposed to sinusodial. Here is a better example of a FM waveform, and here is a better example of an AM waveform. Cacophony 18:31, 4 September 2007 (UTC)[reply]
I agree your static examples are good (and similar to diagrams already on Wikipedia pages). Note however that for an audio signal the modulation polarity is not necessarily wrong, because in monophonic radio it doesn't matter! As to this mathematical nicety that boils down to whether the receiver loudspeaker cone moves out-in or in-out, I accept your point and it looks like NoClip has fixed that.Cuddlyable3 16:13, 5 September 2007 (UTC)[reply]
  • Oppose - as per Cacophony. Don't have a problem with the signal being sinusoidal, but even for an animation it's very low quality. Great idea though, if anyone with the necessary tools/skills could create a higher quality version I'd be a strong support. Bad_germ 20:14, 4 September 2007 (UTC)[reply]
Well yes, this was intended to be a very small animation file that would not slow down loading of pages that use it. As more Wikipedia users get broadband Internet we can become ambitious with higher resolution, colo(u)rs and frames.Cuddlyable3 16:13, 5 September 2007 (UTC)[reply]
It looks the same to me. I wish that I knew more about creating/modifying animated gifs. Cacophony 05:23, 5 September 2007 (UTC)[reply]
Clear your browser cache. Noclip 13:23, 5 September 2007 (UTC)[reply]
  • Oppose. Great from the enc point of view, but technical quality should not be this terrible for an FP, and it doesn't have to be, this can be redone (unlike a historical photograph). --Dschwen 14:03, 5 September 2007 (UTC)[reply]
  • Oppose Questions about the accuracy but more so the quality is too low in my opinion. In the old days we were very limited by what we could do with animated diagrams in terms of quality due to file size, but with broadband virtually everywhere now it isn't such an issue, we could certainly make a much higher res version. I oppose this version but not the idea, its one of the more encylopedic FP ideas we've had recently, I recommend SNOWball closing this unless/until a higher quality version can be provided, possibly with a fourth line with all the waves overlaid.WikipedianProlific(Talk) 15:46, 5 September 2007 (UTC)[reply]
One further thought is this could probably be added to more articles. For example it demonstrates fairly nicely different types of waveform.WikipedianProlific(Talk) 15:48, 5 September 2007 (UTC)[reply]
How big would you like?Cuddlyable3 13:25, 10 September 2007 (UTC)[reply]
Around 1000 X 500px would be nice, anti-aliased if possible. Calibas 00:05, 11 September 2007 (UTC)[reply]
Contact me if you wish to pay me fairly for preparing such a 5x enlarged diagram. IMO it would merely waste page area if posted in Wikipedia. Cuddlyable3 (talk) 08:49, 19 February 2008 (UTC)[reply]

Not promoted MER-C 10:07, 11 September 2007 (UTC)[reply]