This sorts out all the library dependency issues for your system, with the result that specialized scientific and engineering software generally work much better than on other systems. On these UNIX systems, Free software is installed by downloading the source code and compiling it on your machine. Linux and BSD have good real-time performance and gives one full control over everything. With these tools, you can compile specialized software, much the same as on FreeBSD/Linux. In order to use Free scientific/engineering software, you need Xcode (The C compiler provided by Apple, in the App Store), Macports and Homebrew. However, if you use Free software, then it is much the same as Linux/FreeBSD.
If it doesn't work, then you are out of luck, there is nothing you can then do about it and your project is hung - Nuf sed.Ī Macintosh system is better, since it is based on FreeBSD, but it suffers from some of the same software library issues when using precompiled (non-Free) software. The result is that if your special program happens to work, then you are in luck.
The problems are many fold: The operating system scheduler is not real-time, the USB interface is buggy, scientific software invariably require specialized libraries of specific versions, which sometimes clash with libraries that are already installed - known as DLL Hell. These are generally good for playing games, writing letters and doing bookkeeping, but they are not very good for engineering use. Most ordinary mortals use MS Windows computers. To decode it, you need a phase locked loop to convert the FM signal into a varying brightness level - simple as that. The APT signal is 2.4 kHz, frequency modulated, described here and here (APT)Įach facsimilee line starts with a tone burst and the monochrome line is encoded onto a 2.4 kHz tone by frequency modulation at a rate of two scan lines per second.
All three satellites broadcast using an ancient system termed Automatic Picture Transmission (APT). NOAA-15, NOAA-18 and NOAA-19 are probably the easiest to interface to. You also need to make a decent antenna, else you may have more noise than picture. These pictures are interesting, since the weather is always changing. This article describes how to get an image from one of the NOAA polar satellites, using a cheap ($25) little RTL-SDR radio receiver.
The geo satellites can only be received if you happen to live in its antenna footprint (North America), while the polar satellites pass overhead twice a day wherever you are. The NOAA operates both geostationary and polar observers. Weather satellites are generally considered to be the most useful of the lot, since the data is open and not encrypted and the signals are quite strong.
0 kommentar(er)
