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:
Feb. 13, 1996
Filed:
Oct. 06, 1994
Roger L Miller, San Jose, CA (US);
Thomas P Harper, Sunnyvale, CA (US);
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
An anti-lock braking system includes a mechanism for releasing a brake and a digital circuit for determining a wheel velocity and controlling the mechanism to prevent the brake from locking. The digital circuit uses a look-up table which, in response to an address signal, provides a signal indicating a multiplicative inverse of a number between 1 and 2. The circuit receives a measured time for a wheel to move a fixed distance and factors the time as product a power of two and a factor between 1 and 2. An address signal indicating the factor is applied to the look-up table, and the look-up table provides a signal which indicates the inverse of the factor. The signal from the look-up table is then converted to the proper scale for the time. Factoring and conversion may be accomplished with logical shifts so that no multiplier is required. The look-up table may be compressed by not storing bits of inverses, which are constant or only change once within the range of the look-up table and by only storing look-up values for every other number within the range of the look-up table. A code bit in each look-up table value permits generation of correct inverses for values not stored.