Timeline for Does sunlight have a modulation frequency?
Current License: CC BY-SA 4.0
15 events
| when toggle format | what | by | license | comment | |
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| Apr 1 at 23:39 | history | edited | Qmechanic♦ | CC BY-SA 4.0 |
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| Apr 1 at 23:16 | answer | added | John Doty | timeline score: 1 | |
| Apr 1 at 23:15 | answer | added | rob♦ | timeline score: 0 | |
| Apr 1 at 22:27 | comment | added | hyportnex | if Drabowitch can be believed then 1kHz sampling rate will be more than adequate. | |
| Apr 1 at 22:26 | history | edited | Ben S. | CC BY-SA 4.0 |
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| Apr 1 at 22:25 | comment | added | Ben S. | @hyportnex I made some edits to my question, hopefully they clarify what I'm going after. | |
| Apr 1 at 22:24 | comment | added | hyportnex | Drabowitch: "Modern Antennas", p673 "The solar flux $\Phi$ is not actually constant, and three components can be distinguished: (i) a constant component (the so-called 'quiet Sun'); (ii) a slowly varying component, varying on timescales of the order of a week; and (iii) sporadic radio emission (bursts), which last from a few seconds to a few minutes. $\Phi$ is expressed in 'solar flux units', one unit is equivalent to $10^{-22} W/ m^2/Hz$, and values range from below 50 to over 300, a total variability of the order of 8 dB. It is also a fairly strong function of frequency..." | |
| Apr 1 at 22:24 | history | edited | Ben S. | CC BY-SA 4.0 |
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| Apr 1 at 22:15 | comment | added | hyportnex | a very hot thermal noise source source ~6,000K to 11,000K, ... it emits the strongest in the visible region, en.wikipedia.org/wiki/Sunlight, but if you do not have good enough sidelobe suppression it can blind your satellite receiver, too. There are times when the sun is right behind the satellite and these are times of total outage. | |
| Apr 1 at 22:03 | comment | added | Ben S. | @rob Just...sunlight. Writ large. I'm wondering what sort of spectrum it might have given the question exactly as written - just a photodiode sitting outside on a summer day. Will it have discernable features in the spectrum on the order of, say, kilohertz? Megahertz? | |
| Apr 1 at 22:00 | comment | added | Ben S. | @hyportnex I'm interested in this from an EE perspective. What sort of noise source? | |
| Apr 1 at 21:57 | comment | added | rob♦ | Are you looking at the entire face of the Sun, or are you looking with enough resolution to choose feature which affect local brightness, like the convection cells in the photosphere? Do you count the daily modulation mediated by the Earth and its atmosphere? Do you count the 11 year sunspot cycle? | |
| Apr 1 at 21:56 | comment | added | hyportnex | there is a 11-year period sunspot cycle, and there are also much longer ones, see en.wikipedia.org/wiki/Solar_cycle but for an EE it is a noise source | |
| S Apr 1 at 21:43 | review | First questions | |||
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| S Apr 1 at 21:43 | history | asked | Ben S. | CC BY-SA 4.0 |