System for reproducing pulse time modulated waveforms stored along a diffractive track

Abstract From the Canadian patent

A record is provided for storing a pulse time modulated waveform along a recorded track having an axis. The record comprises a substrate having at least one engraved face carrying an embossed print of the recorded track. The engraved face is a phase object constituted by a succession of diffractive elements distributed along the axis in accordance with a sequence of pulses of the waveform. These diffractive elements have non-uniform length and spacing and the width of the embossed print is substantially constant along the axis. The non-uniform length and spacing of the diffractive elements respectively measured along said axis are at least equal to the width of the embossed print. The …