1. A waveform measuring and analyzing instrument having a visual display means comprising digitized memory array means for storage of the coordinates for the visual display means in digitized form, a data acquisition means connected to said memory means for establishing a digitized representation of a waveform, a programmed processor having a program memory, and an interactive user operated control means having a plurality of keystroke means for each of a plurality of basic arithmetic functions of addition, subtraction, multiplication and division and for each of a plurality of compound mathematical functions for reduction and calculation involving the waveform data signals in the memory array means, said program memory including programs for each of said keystroke means, and said processor including means responsive to actuation of said keystroke means to invoke the corresponding program.