Radiant energy – Photocells; circuits and apparatus – Optical or pre-photocell system
Patent
1988-06-16
1990-01-30
Nelms, David C.
Radiant energy
Photocells; circuits and apparatus
Optical or pre-photocell system
250237G, G01D 534
Patent
active
048975443
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a signal processor of a pulse encoder, more particularly, to a signal processor of a pulse encoder for photoelectrically converting light made incident onto a light receiving element into output signals and supplying the photoelectrically converted output signals in parallel to a plurality of circuits to carry out predetermined processes.
BACKGROUND ART
For example, a prior signal processor of a pulse encoder comprises photodiodes and resistors, and when light is made incident onto the photodiodes, a current flows through the photodiodes in response to a strength of the light, and voltage caused by the flow of current through the photodiodes at both ends of the resistors, are picked up as the output signals.
Note, recently a technique for improving a resolution of a pulse encoder has been studied and developed by processing the photoelectrically converted output signals. In the prior art, a signal processor of the pulse encoder for improving the resolution of the pulse encoder such as the above described device has been proposed which, for example, comprises four differential amplifiers and outputs signals having a phase difference of 45 degrees from four output signals having a phase difference of 90 degrees.
However, in the signal processor of the pulse encoder according to the prior art, one photoelectrically converted output signal is directly applied to the input terminals of a plurality of differential amplifiers, and each of the differential amplifiers has a hysteresis resistor connected in parallel between the input terminal and an output terminal thereof. Consequently, the photoelectrically converted output signal applied to the input terminals of the differential amplifiers are affected by the output terminals of the differential amplifiers through hysteresis resistors, so that the four signals processed by the differential amplifiers do not have a correct phase difference of 45 degrees.
DISCLOSURE OF THE INVENTION
The object of the present invention is to perform the predetermined processes correctly without interference, to reduce the power consumption, and to improve the operation speed, in a plurality of the circuits receiving the photoelectrically converted output signals in parallel.
According to the present invention, there is provided a signal processor of a pulse encoder for photoelectrically converting light made incident onto a light receiving element into output signals, and supplying the photoelectrically converted output signals to a plurality of circuits to carry out predetermined processes, characterized in that the signal processor comprises: an operation transistor having a first input to which a first power source voltage is applied through the light receiving element, a second input to which a second power source voltage is applied and commonly connected to the first input, and a third input which is grounded; a plurality of signal output resistors, one ends thereof being supplied with a third power source voltage; and a plurality of signal output transistors of a same number as that of the signal output resistors, having first inputs connected to the other ends of the signal output resistors, second inputs connected to the second input of said operation transistor, and third inputs which are grounded, to be operated in accordance with the operation transistor, the photoelectrically converted output signals to be supplied in parallel to the plurality of circuits being separately supplied from respective connections between the signal output resistors and the first inputs of the signal output transistors.
According to the signal processor of the pulse encoder of the present invention having the above described configuration, photoelectrically converted output signals applied in parallel to the input terminals of a plurality of differential amplifiers are separately supplied from the connection portion between each signal output resistor and the first input of each signal output transistor, so that the signal processing of
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patent: 4833316 (1989-05-01), Yoneda
Kikuchi Hirofumi
Kobari Katsuo
Takekoshi Yoshitaka
Taniguchi Mitsuyuki
Allen Stephone B.
Fanuc Ltd.
Nelms David C.
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