Directional guidance method for the blind using time separation pitch discrimination of triple pulse signals

Abstract

A guidance system for the blind, using time separation pitch (TSP) was simulated. Listeners estimated a simulated straight line course perpendicular to and bisecting a line between two horizontally separated transmitters, one transmitting a pulse doublet and the other, a single pulse. The course was represented by the coincidence of the single pulse with the doublet's center, forming a triplet of identical broadband, evenly spaced pulses. In test signals simulating deviations from the course, interpulse intervals were varied by changing the timing of the second pulse. The subjects' ability to discriminate pulse separations in triplets was measured. Next, subjects manipulated the timing of the second pulse of test signals to produce a triplet containing two equal intervals. Subjects' ability to discriminate and manipulate signals suggests that a trained listener could correct veering by observing changes in TSP.