{ "items" : [
    { "id" : "http://dbpedia.org/resource/Envelope_(waves)"
      "properties" : {
        "http://www.w3.org/2000/01/rdf-schema#comment" : [ "In physics and engineering, the envelope function of an oscillating signal is a smooth curve outlining its extremes. The envelope thus generalizes the concept of a constant amplitude. The figure illustrates a modulated sine wave varying between an upper and a lower envelope. The envelope function may be a function of time, space, angle, or indeed of any variable." ] ,
        "http://www.w3.org/2000/01/rdf-schema#seeAlso" : [ "http://dbpedia.org/resource/Diffraction",
          "http://dbpedia.org/resource/Wave",
          "http://dbpedia.org/resource/K·p_perturbation_theory",
          "http://dbpedia.org/resource/Beat_(acoustics)",
          "http://dbpedia.org/resource/Group_velocity" ] ,
        "http://xmlns.com/foaf/0.1/depiction" : [ "http://commons.wikimedia.org/wiki/Special:FilePath/Signal_envelopes.png" ] ,
        "http://dbpedia.org/ontology/thumbnail" : [ "http://commons.wikimedia.org/wiki/Special:FilePath/Signal_envelopes.png?width=300"] } } }
