Radiant energy – Photocells; circuits and apparatus – Optical or pre-photocell system
Patent
1990-01-30
1992-06-09
Nelms, David C.
Radiant energy
Photocells; circuits and apparatus
Optical or pre-photocell system
341 13, G01D 534
Patent
active
051209543
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an improvement applicable to an encoder. More specifically, this invention relates to an improvement applicable to a plurality of means for correction of offset, difference in amplitude and/or difference in phase which may occur in output signals of an optical encoder.
2. Description of the Related Art
Referring to FIG. 1, an exemplary means available in the prior art for correction of offset, difference in amplitude and/or difference in phase existing in output signals of an optical encoder.
The upper half of FIG. 1 illustrates an A phase encoder, and the lower half of FIG. 1 illustrates a B phase encoder. The A phase encoder and the B phase encoder are substantially identical to each other, excepting each of them has a function to individually detect the angular position of two independent parts of a single rotator, the angular position of the two independent parts differring from each other by 90 degrees in terms of phase.
A first means for sensing angular position of A phase (1A) detects the inverse phase of the phase which a second means for sensing angular position of A phase (2A) detects. The output signals of these two means (1A) and (1B) are input to a sine wave generator means of A phase (3A), which subtracts the one of the two signals from the other of the two signals and generates a sine wave signal which represents the angular position of the rotator. If the sine wave generator means of A phase (3A) happens to generate a sine wave signal containing an offset caused by a difference in amplitude existing between the output signal of the first means for sensing angular position (1A) and the output signal of the second means for sensing angular position (2A), an operational amplifier for erasing offset of A phase (31A) is employed for the purpose to erase the offset existing in the output signal of the A phase encoder. In other words, an adjuster means e.g. a volume resistor of the operational amplifier for erasing offset of A phase (31A) is adjusted to adjust the amplification factor of the operational amplifier for erasing offset of A phase (31A), resultantly causing the amplitude of the output signal of the first means for sensing angular position of A phase (1A) to become equal to the amplitude of the output signal of the second means for sensing angular position of A phase (2A).
Similar operation is conducted also for the B phase encoder which detects the angular position of a part whose angular position differs from that of the part of the same rotator whose angular position is detected by the A phase encoder, by 90 degrees in terms of phase. In other words, the output signals of a first means for sensing angular position of B phase (1B) and the output signals of a second means for sensing angular position of B phase (2B) are input to a sine wave generator means of B phase (3B), which subtracts the one of the two signals from the other of the two signals and generates a sine wave signal which represents the angular position of the rotator. If the sine wave generator means of B phase (3B) happens to generate a sine wave signal containing an offset caused by a difference in amplitude existing between the output signal of the first means for sensing angular position (1B) and the output signal of the second means for sensing angular position (2B), an operational amplifier for erasing offset of B phase (31B) is employed for the purpose to erase the offset existing in the output signal of the B phase encoder. In other words, an adjuster means e.g. a volume resister of the operational amplifier for erasing offset of B phase (31B) is adjusted to adjust the amplification factor of the operational amplifier for erasing offset of B phase (31B), resultantly causing the amplitude of the output signal of the first means for sensing angular position of B phase (1B) to become equal to the amplitude of the output signal of the second means for sensing angular position of B phase (2B).
If a difference in amplitude happens to exis
REFERENCES:
patent: 4686510 (1987-08-01), Baker
patent: 4691192 (1987-09-01), Baker
patent: 4970511 (1990-11-01), Mills
Allen S.
Fanuc Ltd.
Nelms David C.
LandOfFree
Circuit for adjusting encoder signals does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Circuit for adjusting encoder signals, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Circuit for adjusting encoder signals will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1806211