specdisp — Displays the magnitude values of the spectrum.
iprd -- the period, in seconds, of each new display.
iwtflg (optional, default=0) -- wait flag. If non-zero, hold each display until released by the user. The default value is 0 (no wait).
wsig -- the input spectrum.
Displays the magnitude values of spectrum wsig every iprd seconds (rounded to some integral number of wsig's originating iprd).