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1495Re: applying ( Spectrum Lab web server Fftlog1.txt data processing php JS

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  • dariusjack2006
    May 2 5:41 AM
      Wolf, Mark,

      a nice graphical interface to JSON structures

      http://www.json.org/

      To implement interactivity, syntax and JSON structures should be generated on-the-fly by http request.

      Header comes first for parsing of data structures in JSON stream.
      Support for time-stamp could let us build network of meteor watching
      stations and have central station processing live data streams on-the-fly, generating graphics.

      Fftlog1.txt is made of header line + data, header line + data loop.
      Updated time stamp can come with header.



      --- In SpectrumLabUsers@yahoogroups.com, Mark McCarron <mark.mccarron@...> wrote:
      >
      > Wolf,
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      > You can use an JSON Array.
      >
      > http://www.w3resource.com/JSON/structures.php
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      > The format is [Value1, Value2, Value3...etc], or in your case [I,Q,I,Q...etc]. No need for key/value pairs.
      >
      > It is also possible to read it as a stream:
      >
      > http://stackoverflow.com/questions/444380/is-there-a-streaming-api-for-json
      >
      > Regards,
      >
      > Mark McCarron
      >
      > To: SpectrumLabUsers@yahoogroups.com
      > From: dl4yhf@...
      > Date: Wed, 1 May 2013 08:52:09 +0200
      > Subject: Re: [SpectrumLabUsers] Re: applying ( Spectrum Lab web server Fftlog1.txt data processing php JS
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      > Greetings all,
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      > Javascript / JSON experts out there ?
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      > How would you format the data for a *complex* FFT, i.e. two components
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      > per frequency bin, in a JSON response with the minimum possible
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      > overhead, when its impossible to have different data type *definitions*
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      > and the data itself ? (this is one of the things I always missed in
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      > Javascript... I first want to *declare* a data type (struct in "C" or
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      > record in Pascal) before using it, but in j.s. / JSON they embed the
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      > names of the struct (or array) members in the response with the data
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      > themselves.
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      > Which is very very unfortunate if you have an array of say 524288
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      > complex frequency bins, and have to put the NAMES of each component in
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      > each frequency bin because you cannot declare data types in advance ?
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      > For example, in "C" (not C++) one would first declare a complex number
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      > as a struct like this
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      > typedef struct
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      > { float re;
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      > float im;
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      > } T_Complex;
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      > and then use it in an array of complex numbers like this:
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      > T_Complex fft[524288] = { {0.1, 0.2}, {0.1, 0.3}, {0.1, 0.4}, ..... };
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      > ( the receiver of such a line would of course need to know what
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      > T_Complex is; since it's unnecessary to pass that in the server response)
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      > How to form such two-dimensional arrays in JSON, without having to put
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      > the name of each component in each array element (which would be an
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      > awful waste of memory / network bandwidth) ?
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      > Or drop JSON (to read FFTs from SL via its HTTP server) and use a simple
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      > but flexible, self-defined format instead, which can be parsed in any
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      > programming language ?
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      > All the best,
      >
      > Wolf .
      >
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