ash; usually about $25).
     The Bessel function graph is from Corrington, "Variation of Bandwidth with Modulation Index in FM",
     The picture below of an early radio is from Armstrong, "A Method of Reducing Disturbances in Radio
     Signaling by a System of FM".  The Carson quote is also from that paper (originally published
     in Proc. IRE, Vol 24, No 5, pp 689-740, May, 1936, with Carson's paper referred to as
     "Notes on the theory of modulation", Proc. IRE, vol 10, pp 57-82, Feb 1922).

LeBru