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:
Nov. 06, 1990
Filed:
Jun. 06, 1988
Charles M Riggle, Colorado Springs, CO (US);
Lih-Jyh Weng, Lexington, MA (US);
Digital Equipment Corporation, Maynard, MA (US);
Abstract
A data demodulator assigns a binary value to the signal recorded in a transition cell based on the amplitude of the signal in the transition cell, the amplitudes of the signal in adjacent transition cells and system experience in categorizing how recording non-linearities and system noise effect the signals. The demodulator samples a selected number of times the recorded signal in the transition cell for which a binary value is to be determined and the recorded signal in a selected number of transition cells adjacent to that cell. It then converts the amplitude of each of the signal samples to a digital symbol. Next, it concatenates portions of the digital symbols to form an interpretation word. It uses this word to enter a stored lookup table which contains binary values, and assigns to the transition cell signal the binary value associated with the word. The table associates a value with a particular word or group of words based on system experience and the demodulation of known signals into interpretation words. The binary values assigned to a number of cells may be combined to form a code word which may be decoded and corrected using soft decoding techniques.