Radiant energy – Photocells; circuits and apparatus – Optical or pre-photocell system
Reexamination Certificate
2001-07-03
2003-12-09
Luu, Thanh X. (Department: 2878)
Radiant energy
Photocells; circuits and apparatus
Optical or pre-photocell system
C341S013000
Reexamination Certificate
active
06660996
ABSTRACT:
TECHNICAL FIELD
The present invention relates generally to encoder systems used for tracking movement of mechanical structures and, more particularly, to a system and method for analyzing encoder output signals for information regarding phase and amplitude relationship of the signals.
BACKGROUND OF THE INVENTION
A large number of different encoder systems have been used in the past. A typical encoder outputs two different signals on different channels. In an ideal situation the encoder output signals are in quadrature (90° out of phase with each other) and have the same amplitude and period. Amplitudes of the two encoder output signals repeatedly intersect. Different techniques have been used to determine when the encoder output signals are not exactly 90° out of phase and/or when the max to min amplitudes of the signals do not match.
It would be advantageous to provide a system and method useful in considering the phase and amplitude relationship between two encoder output signals.
SUMMARY OF THE INVENTION
In one aspect, a method for determining an intersection point between first and second encoder output signals involves: (a) defining a capture start position; (b) determining when an amplitude of the second encoder output signal crosses the capture start position; (c) after step (b), initiating capture of a plurality of first sample points of the first encoder output signal and a plurality of second sample points of the second encoder output signal; (d) storing the captured first and second sample points; and (e) examining the stored first and second sample points to define the intersection point.
In another aspect, a method of examining phase and amplitude relationship between first and second encoder output signals which are out of phase and which repeatedly intersect involves: (a) determining a first intersection point between the first and second encoder output signals when the first encoder output signal is increasing and the second encoder output signal is decreasing; (b) determining a second intersection point between the first encoder output signal and an inverse of the second encoder output signal when the first encoder output signal is increasing and the second encoder output signal is increasing; (c) determining a third intersection point between the first and second encoder output signals when the first encoder output signal is decreasing and the second encoder output signal is increasing; and (d) determining a fourth intersection point between the first encoder output signal and an inverse of the second encoder output signal when the first encoder output signal is decreasing and the second encoder output signal is decreasing.
In a further aspect, an encoder signal analysis system for examining first and second encoder output signals includes a controller receiving the first and second encoder output signals. The controller determines: (i) a first intersection point between the first and second encoder output signals when the first encoder output signal is increasing and the second encoder output signal is decreasing, (ii) a second intersection point between the first encoder output signal and an inverse of the second encoder output signal when the first encoder output signal is increasing and the second encoder output signal is increasing, (iii) a third intersection point between the first and second encoder output signals when the first encoder output signal is decreasing and the second encoder output signal is increasing, and (iv) a fourth intersection point between the first encoder output signal and an inverse of the second encoder output signal when the first encoder output signal is decreasing and the second encoder output signal is decreasing.
In still a further aspect, an encoder signal analysis system for determining a intersection point between first and second encoder output signals includes a controller receiving the first and second encoder output signals. The controller includes a stored capture start position. The controller determines when an amplitude of the second encoder output signal crosses the capture start position and then initiates capture of a plurality of first sample points of the first encoder output signal and a plurality of second sample points of the second encoder output signal. The controller stores the captured first and second sample points and examines the stored first and second sample points to define the intersection point.
REFERENCES:
patent: 4224515 (1980-09-01), Terrell
patent: 4259570 (1981-03-01), Leonard
patent: 4491826 (1985-01-01), Krogh et al.
patent: 4529964 (1985-07-01), Minami et al.
patent: 4547667 (1985-10-01), Sasaki et al.
patent: 4606008 (1986-08-01), Wason
patent: 4678910 (1987-07-01), Hara et al.
patent: 4682343 (1987-07-01), Pfiffner
patent: 4751383 (1988-06-01), Ueyama
patent: 5129725 (1992-07-01), Ishizuka et al.
patent: 5260769 (1993-11-01), Ieki et al.
patent: 5414516 (1995-05-01), Morishita et al.
patent: 5572018 (1996-11-01), Taniguchi et al.
patent: 5750984 (1998-05-01), Ieki
patent: 5774068 (1998-06-01), Seki
patent: 5939714 (1999-08-01), Park
patent: 5981942 (1999-11-01), Ieki
patent: 6043771 (2000-03-01), Clark et al.
patent: 6087654 (2000-07-01), Durham, III
patent: 6175109 (2001-01-01), Setbacken et al.
patent: 6355927 (2002-03-01), Snyder
Adkins Christopher Alan
Barkley Lucas David
Marra, III Michael Anthony
Lexmark International Inc.
Luu Thanh X.
Nieberding Michael J.
LandOfFree
System and method for examining relationship between... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with System and method for examining relationship between..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and System and method for examining relationship between... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3095907