The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 10, 1989
Filed:
Sep. 16, 1987
Steven A Tretter, Silver Spring, MD (US);
Penril Corporation, Rockville, MD (US);
Abstract
A modem and method for modulation-demodulation of a received analog signal. The modem receives sixteen bits at four bits per baud. The 8 D Block Encoder encodes nine of the sixteen bits into 12 Z-bits which are used to specify a sequence of four 2 D constellation points. These 2 D constellation points correspond to a sequence of four 2 D subsets of a 8 D subtype selected. The differential encoder differentially encodes two of the sixteen bits to make the code transparent to a 90 degree rotation. The rate 3/4 convolutional encoder generates a check bit and a bit converter converts the check bit, the differential encoded bits and the remaining five bits into 8 Z-bits. The result is an 8 D trellis with a 20-point 2 D constellation.