SEQUENCY FILTERS BASED ON WALSH FUNCTIONS FOR SIGNALS WITH THREE SPACE VARIABLES

• US 3,668,639 A
• Filed: 05/07/1971
• Issued: 06/06/1972
• Est. Priority Date: 05/07/1971
• Status: Expired due to Term

• Current Assignee: ITT Corporation (ITT, Inc.)
• Original Assignee: Henning Friedolf Harmuth
• Inventors: Harmuth, Henning Friedolf
• Primary Examiner(s): Yusko, Donald J.
• Application Number:
  US05/141,328
• Time in Patent Office: 396 Days
• Field of Search: 340/166,324,339 178/5.4MA,7.3D
• US Class Current: 345/6
• CPC Class Codes: G09G 3/003 to produce spatial visual effects
• CPC Class Codes: G09G 3/20 for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters

Abstract

A sequency sampling filter based on Walsh Functions for signals having three space variables, x, y and z. Voltages derived from the space domain are transformed into voltages in a sequency domain. The filtering process is performed by not feeding certain voltages a (k,m,n) to a circuit which performs the inverse transformation of voltages in the sequency domain back into the space domain.

Claims

1. An apparatus for displaying three-dimensional Walsh functions by light emission comprising:

a three-dimensional crossbar matrix comprising a first plurality of wires parallel to the x-axis of a threedimensional coordinate system;

a second plurality of wires parallel to the y-axis of said coordinate system;

a third plurality of wires parallel to the z direction of said coordinate system, the intersection of said first, second and third plurality of wires forming crosspoints;

a first Walsh function generator coupled to said first plurality of wires;

a second Walsh function generator coupled to said second plurality of wires;

a third Walsh function generator coupled to said third plurality of wires; and

light emitting means coupled to each of said crosspoints for emitting light when the product of the Walsh functions applied to each of said crosspoints by said first, second and third Walsh function generators represent a positive voltage.

2. An apparatus according to claim 1 wherein exclusive OR gates are coupled to the crossing of said first and second plurality of wires.

3. An apparatus according to claim 1 wherein an exclusive OR gate and a single-pole double-throw switch is coupled to each of said crosspoints further comprising a summing amplifier to which are fed in parallel the outputs of said switches, the output of said summing amplifier representing the Walsh-Fourier transform of the applied signal.