Electrical computers: arithmetic processing and calculating – Electrical digital calculating computer – Particular function performed
Reexamination Certificate
1999-11-30
2003-08-05
Ngo, Chuong Dinh (Department: 2124)
Electrical computers: arithmetic processing and calculating
Electrical digital calculating computer
Particular function performed
C708S653000, C360S075000
Reexamination Certificate
active
06604121
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to digital dividers, and more particularly to devices and methods able to estimate a digital quotient of several bits in about 5 to 500 clock cycles.
BACKGROUND OF THE INVENTION
Fast digital dividers generally fall into one of two categories: calculation-type and lookup-type. Although designing logic to calculate a quotient with greater precision is not difficult, the number of gates becomes exponentially more costly for each additional bit of precision required. As a result, calculation-type dividers typically provide only a few bits of precision.
Lookup-type dividers receive an input that combines the numerator and denominator. They then output a quotient retrieved from a table, typically implemented in read-only memory (ROM). Like the logic of calculation-type dividers, expanding ROM to enhance precision is not complex but quickly become unwieldy as precision increases further.
As a result, applications which require greater precision often resort to doing so in software. This greatly reduces the speed with which division can be performed. For ascertaining quotients in time-critical applications such as a motion controller that senses its position each millisecond, there is a continuing need for a precise digital divider that is faster than a code-implemented divider and more precise than a typical calculation-type or lookup-type divider.
SUMMARY OF THE INVENTION
Devices and methods are provided for estimating a quotient efficiently, using a table that is smaller than that of a conventional lookup-type divider of a like precision. The devices include a numerator register feeding a succession of bits or words comprising the numerator value into a forward signal path. The forward path includes a partial quotient generator (PQG) able to generate a succession of signals indicative of portions of the quotient. After passing through an accumulator, each partial quotient is then latched. The devices further include a bit-shifting feedback signal path emerging from the latch output and terminating into another input of the accumulator. The devices further include control circuitry for triggering the numerator register(s) and/or the latch(es) to change state.
Methods of the present invention include steps of receiving a numerator and a denominator each as a digitized value, parsing the numerator, providing at least a portion of the numerator with the denominator to a PQG, and latching the output. The methods further include reducing the result approximately by a factor of about 2 (or 4 or some larger power of two) summing the reduced result with at least one additional value obtained from the PQG.
A most preferred device of the present invention finds advantageous use in a disc drive servo control system, the device calculating a formula taking the general form (F/G)/(F/G+H/J).
REFERENCES:
patent: 4412161 (1983-10-01), Cornaby
patent: 4466077 (1984-08-01), Iannucci et al.
patent: 5105378 (1992-04-01), Mori
patent: 5206647 (1993-04-01), Stone
patent: 5576909 (1996-11-01), Dierkes et al.
patent: 5602693 (1997-02-01), Brunnett et al.
patent: 5644639 (1997-07-01), Naciri et al.
patent: 5760990 (1998-06-01), Ukani et al.
patent: 5774297 (1998-06-01), Hampshire et al.
PYE TMC Limited, (untitled book section),(published circa 1980) pp. 254 through 264 and 392.
Ell Travis E.
Morris John C.
McCarthy Mitchell K.
Ngo Chuong Dinh
Seagate Technology LLC
LandOfFree
Digital division device and method using a reduced-sized... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Digital division device and method using a reduced-sized..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Digital division device and method using a reduced-sized... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3094323