Method of detecting and evaluating photometric signals and device for carrying out the method
First Claim
1. In a method for detecting and evaluating the optical properties of a specimen including producing alternating light and dark phases from a light source, detecting light from the light source by way of an analog specimen to produce a signal, integrating and digitalizing the signal from the detector during the light phase and during the dark phase and subtracting the integral obtained during the dark phase from that obtained during the light phase, the improvement wherein the steps of integrating and digitalizing comprise:
- forming a first total integral in a first state including a whole number of measurement voltage periods each including one light and one dark phasecomprising the steps in each period of integrating the detected signal during a part of the light phase with a single integrator and integrating the detected signal with the reversed polarity with the same single integrator during a part of the dark phase equal in length to the part of the light phase and digitalizing the total integral with the same single integrator.
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Abstract
A method and device for detecting and evaluating the optical properties of a specimen, utilizing a light source that has alternating light and dark phases, a detector that picks up light from the light source by way of the specimen being examined, and a circuit that integrates and digitalizes the signals received from the detector, that includes an integrator, and that can be connected to the detector. The signals emitted from the detector are integrated both during at least part of the light phase and during at least part of the dark phase. The integral obtained during the dark phase is subtracted from that obtained during the light phase in order to determine the results. The integrator that is used to integrate the signals is used like an analog-to-digital converter of the double-integration type to convert the integral into a digital signal. To achieve maximum precision and simplicity in the integration and digitalization phase, each part of the light or dark phase is followed by a measurement-voltage period during which the signals coming from the detector are applied in sequence and with opposite mathematical signs to a single integrator. Integration is carried out over a whole number of measurement-voltage periods to form a total integral.
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Citations
13 Claims
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1. In a method for detecting and evaluating the optical properties of a specimen including producing alternating light and dark phases from a light source, detecting light from the light source by way of an analog specimen to produce a signal, integrating and digitalizing the signal from the detector during the light phase and during the dark phase and subtracting the integral obtained during the dark phase from that obtained during the light phase, the improvement wherein the steps of integrating and digitalizing comprise:
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forming a first total integral in a first state including a whole number of measurement voltage periods each including one light and one dark phase comprising the steps in each period of integrating the detected signal during a part of the light phase with a single integrator and integrating the detected signal with the reversed polarity with the same single integrator during a part of the dark phase equal in length to the part of the light phase and digitalizing the total integral with the same single integrator. - View Dependent Claims (2, 3, 4, 5, 6)
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7. In a device for detecting and evaluating the optical properties of a specimen having a light source, means for producing alternating light and dark phases from a light source, first means for detecting light from the light source by way of a specimen and produce an analog signal, an integrating and digitalizing circuit receptive of the signal from the detecting means during the light phase and during the dark phase means for subtracting the integral obtained during the dark phase from that obtained during the light phase, the improvement wherein the integrating and digitalizing circuit comprises:
- means forming a first total integral during first stage including a whole number of measurement-voltage periods each including one light and one dark phase a single integrator and means synchronized with the means producing the light and dark phases for applying in each period the detected signal during a part of the light phase to the input of the single integrator and for applying the detected signal with the opposite polarity during a part of the dark phase equal in length to the part of the light phase to the input of the single integrator and means for digitalizing the total integral comprising the single integrator.
- View Dependent Claims (8, 9, 10, 11, 12, 13)
Specification