might very well be related (Envelope is the message signal which is off set by a constant value to avoid synchronization at the receiver. ) since the information was plotted in a graph format, and looked like a sine wave.. (well, not quite a sine wave, but a amplification wave.. (starting the left, with a steep rise, cresting, coming down a bit, staying almost level for a while, then a steep decline.. (dating myself--but very much like the signal from an old vacuum tube!)))
and since circut boards (integrated circuts) and transistors were just coming into play with the new jets, and -- and there use and performence was being tested at the same time.. the engineers would likely look at the graph and see it similar to the envelope


my other obsession