An optical signal measurement system based on differential comparison compensation of reference light and reference light

Abstract

The present invention proposes an optical signal measurement system based on differential comparison compensation of reference light and reference light, which is realized by the following technical scheme: the light source provides a homologous measurement light signal and a reference light signal, the measurement light signal is attenuated after passing through the measurement medium, and then the measurement voltage signal is obtained after passing through the photoelectric conversion circuit, signal amplification circuit, and filtering circuit; the reference light signal directly passes through the same photoelectric conversion circuit, signal amplification circuit, and filtering circuit to obtain a reference voltage signal; the measurement voltage signal and the reference voltage signal are obtained through a differential comparison circuit to obtain a voltage signal that can be collected by an AD converter, and the CPU reads the AD collected signal through the data bus to calculate the measurement light intensity. When the light source fluctuates, the homologous measurement light and reference light fluctuate at the same time, and the measurement error caused by the power supply fluctuation is eliminated by the differential comparison circuit. The present invention aims to provide an optical signal measurement method with high stability and not affected by light source fluctuations.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical signal measurement, and in particular, relates to an optical signal measurement system based on differential comparison and compensation of reference light and benchmark light. Background Art

[0002] Optical fiber has good insulation properties, explosion-proof, corrosion-resistant, strong anti-interference ability and easy miniaturization. The attenuation degree of the optical signal transmitted in the optical fiber is inconsistent in the air and fuel. The measurement light is emitted through the optical fiber by a fixed light source, and the measured light intensity is attenuated after the optical fiber passes through the fuel. When the oil immersion height changes, the attenuation degree of the measured light intensity changes linearly. By measuring the light intensity in the optical fiber, the corresponding fuel height can be calculated. Based on the above characteristics of optical fiber, optical signal measurement through optical fiber has been rapidly developed in the field of aviation fuel measurement.

[0003] The optical signal measurement method currently used for aviation fuel measurement uses a light source to directly send a measurement light signal through an optical fiber, and collects the light signal intensity in the optical fiber to calculate the fuel altitude. Due to the complex and changeable electromagnetic environment on the aircraft, it is very easy to cause light source fluctuations. When the light source fluctuates, the measured light intensity also changes. In the actual measurement process, it is difficult to determine whether the current change in light intensity is caused by normal attenuation caused by the light propagation medium or light source fluctuations. Therefore, the measurement error is extremely large in the actual measurement process. Summary of the invention

[0004] In view of the above defects and needs of the prior art, the present invention proposes an optical signal measurement system based on differential comparison compensation of reference light and reference light, including a light source, a measurement light signal unit, a reference light signal unit, a measurement channel, a reference channel, a differential comparison circuit, a data acquisition unit, and a data processing unit; the light source of the present invention provides a homologous measurement light signal and a reference light signal, and when the light source fluctuates, the homologous measurement light and reference light fluctuate at the same time, and the measurement error caused by power supply fluctuation is eliminated through the differential comparison circuit. Thus, a more stable and accurate measurement is achieved.

[0005] The specific implementation contents of the present invention are as follows:

[0006] The present invention proposes an optical signal measurement system based on differential comparison compensation of reference light and reference light, comprising a light source, a measurement optical signal unit, a reference optical signal unit, a measurement channel, a reference channel, a differential comparison circuit, a data acquisition unit, and a data processing unit;

[0007] The light source is connected to the measuring light signal unit and the reference light signal unit respectively, and is connected to the measuring channel and the reference channel respectively through the measuring light signal unit and the reference light signal unit, and then connected to the differential comparison circuit through the measuring channel and the reference channel; a signal attenuation unit is provided in the measuring channel;

[0008] The differential comparison circuit, the data acquisition unit, and the data processing unit are connected in sequence;

[0009] The differential comparison circuit includes an instrumentation amplifier FX620, an adjustable resistor RP1, and a resistor R1;

[0010] The positive input terminal of the instrument amplifier FX620 is connected to the measurement channel; the negative input terminal of the instrument amplifier FX620 is connected to the reference channel;

[0011] Terminal 5 of the instrument amplifier FX620 is grounded; the resistor R1 and the adjustable resistor RP1 are connected in parallel and then bridged between terminals 8 and 1 of the instrument amplifier FX620.

[0012] In order to better implement the present invention, further, the measurement channel and the reference channel both include a photoelectric conversion unit, a signal amplification unit, and a filtering circuit;

[0013] The input end of the signal attenuation unit in the measurement channel is connected to the measurement light signal unit, and the output end is connected to the photoelectric conversion unit, the signal amplification unit, and the filter circuit of the measurement channel in sequence, and is connected to the positive input end of the instrument amplifier FX620 of the differential comparison circuit through the filter circuit;

[0014] The input end of the photoelectric conversion unit in the reference channel is connected to the reference optical signal unit, and the output end is connected to the signal amplification unit and the filter circuit of the reference channel in sequence, and is connected to the negative input end of the instrument amplifier FX620 of the differential comparison circuit through the filter circuit.

[0015] In order to better implement the present invention, further, the filter circuit adopts an RC filter circuit.

[0016] In order to better implement the present invention, further, the data acquisition unit adopts an AD conversion circuit.

[0017] In order to better implement the present invention, further, the data processing unit adopts a CPU processing chip.

[0018] In order to better implement the present invention, further, the signal attenuation unit adopts a measuring medium to attenuate the measuring light signal through the measuring medium.

[0019] The present invention has the following advantages and beneficial effects:

[0020] The present invention provides a homologous measurement light signal and a reference light signal through a light source. After the measurement light signal passes through a measurement medium, the signal is attenuated, and then a measurement voltage signal is obtained after passing through a photoelectric conversion circuit, a signal amplification circuit, and a filtering circuit; the reference light signal directly passes through the same photoelectric conversion circuit, a signal amplification circuit, and a filtering circuit to obtain a reference voltage signal; the measurement voltage signal and the reference voltage signal are passed through a differential comparison circuit to obtain a voltage signal that can be collected by an AD converter, and the CPU reads the AD collected signal through a data bus to calculate the measurement light intensity. When the light source fluctuates, the homologous measurement light and reference light fluctuate at the same time, and the measurement error caused by the power supply fluctuation is eliminated through the differential comparison circuit, thereby achieving a more accurate and stable measurement effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of the connection of specific modules of the present invention;

[0022] Figure 2 Schematic diagram of the circuit principle of the differential comparison circuit of the present invention. DETAILED DESCRIPTION

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. It should be understood that the described embodiments are only part of the embodiments of the present invention, not all of the embodiments, and therefore should not be regarded as limiting the scope of protection. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technical personnel in this field without making creative work are within the scope of protection of the present invention.

[0024] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "disposed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0025] Embodiment 1:

[0026] This embodiment proposes an optical signal measurement system based on differential comparison compensation of reference light and reference light. Figure 1 As shown, it includes a light source, a measuring light signal unit, a reference light signal unit, a measuring channel, a reference channel, a differential comparison circuit, a data acquisition unit, and a data processing unit;

[0027] The light source is connected to the measuring light signal unit and the reference light signal unit respectively, and is connected to the measuring channel and the reference channel respectively through the measuring light signal unit and the reference light signal unit, and then connected to the differential comparison circuit through the measuring channel and the reference channel; a signal attenuation unit is provided in the measuring channel;

[0028] The differential comparison circuit, the data acquisition unit and the data processing unit are connected in sequence.

[0029] Working principle: The light source of the present invention provides a homologous measurement light signal and a reference light signal. When the light source fluctuates, the homologous measurement light and reference light fluctuate at the same time, and the measurement error caused by power supply fluctuation is eliminated through the differential comparison circuit, thereby achieving a more stable and accurate measurement.

[0030] Embodiment 2:

[0031] In this embodiment, based on the above-mentioned embodiment 1, in order to better realize the present invention, further, the measurement channel and the reference channel both include a photoelectric conversion unit, a signal amplification unit, and a filtering circuit;

[0032] The input end of the signal attenuation unit in the measurement channel is connected to the measurement light signal unit, and the output end is connected to the photoelectric conversion unit, the signal amplification unit, and the filter circuit of the measurement channel in sequence, and is connected to the positive input end of the instrument amplifier FX620 of the differential comparison circuit through the filter circuit;

[0033] The input end of the photoelectric conversion unit in the reference channel is connected to the reference optical signal unit, and the output end is connected to the signal amplification unit and the filter circuit of the reference channel in sequence, and is connected to the negative input end of the instrument amplifier FX620 of the differential comparison circuit through the filter circuit.

[0034] Working principle: Figure 1 As shown: the light source provides a homologous measurement light signal and a reference light signal. The measurement light signal is attenuated after passing through the measurement medium, and then the measurement voltage signal is obtained after passing through the photoelectric conversion circuit, signal amplification circuit, and filtering circuit; the reference light signal directly passes through the same photoelectric conversion circuit, signal amplification circuit, and filtering circuit to obtain a reference voltage signal; the measurement voltage signal and the reference voltage signal are obtained through a differential comparison circuit to obtain a voltage signal that can be collected by the AD converter. The CPU reads the AD collected signal through the data bus to calculate the measurement light intensity. When the light source fluctuates, the homologous measurement light and reference light products fluctuate at the same time, and the measurement error caused by the power supply fluctuation is eliminated through the differential comparison circuit. The photoelectric conversion circuit can be composed of a photodiode to convert the light signal into a current signal, and the signal amplification circuit can be composed of an operational amplifier to convert the circuit signal into a voltage signal.

[0035] The other parts of this embodiment are the same as those of the above-mentioned embodiment 1, and thus will not be described in detail.

[0036] Embodiment 3:

[0037] In this embodiment, based on any one of the above embodiments 1-2, the differential comparison circuit includes an instrumentation amplifier FX620, an adjustable resistor RP1, and a resistor R1;

[0038] The positive input terminal of the instrument amplifier FX620 is connected to the measurement channel; the negative input terminal of the instrument amplifier FX620 is connected to the reference channel;

[0039] Terminal 5 of the instrument amplifier FX620 is grounded; the resistor R1 and the adjustable resistor RP1 are connected in parallel and then bridged between terminals 8 and 1 of the instrument amplifier FX620.

[0040] Working principle: Figure 2 The differential comparison circuit shown uses the low-power instrument amplifier FX620, whose voltage gain can be changed with only one external resistor. The amplifier circuit is set to a fixed resistor and a potentiometer in parallel. The output voltage, that is, the range of the AD converter collecting signals, can be adjusted by changing the resistance value of the amplifier resistor.

[0041] The other parts of this embodiment are the same as any of the above embodiments 1-2, so they are not repeated here.

[0042] Embodiment 4:

[0043] In this embodiment, based on any one of the above embodiments 1-3, in order to better realize the present invention, further, the filter circuit adopts an RC filter circuit.

[0044] The other parts of this embodiment are the same as any one of the above embodiments 1-3, so they are not repeated here.

[0045] Embodiment 5:

[0046] In this embodiment, based on any one of the above embodiments 1-4, in order to better implement the present invention, the data acquisition unit further adopts an AD conversion circuit.

[0047] The other parts of this embodiment are the same as any one of the above embodiments 1-4, so they are not repeated here.

[0048] Embodiment 6:

[0049] In this embodiment, based on any one of the above embodiments 1-5, in order to better realize the present invention, the data acquisition unit further adopts an AD conversion circuit.

[0050] The other parts of this embodiment are the same as any one of the above embodiments 1-5, so they are not repeated here.

[0051] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification or equivalent change made to the above embodiment based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. An optical signal measurement system based on differential comparison compensation of reference light and reference light, characterized in that: It includes a light source, a measuring light signal unit, a reference light signal unit, a measuring channel, a reference channel, a differential comparison circuit, a data acquisition unit, and a data processing unit; The light source is connected to the measuring light signal unit and the reference light signal unit respectively, and is connected to the measuring channel and the reference channel respectively through the measuring light signal unit and the reference light signal unit, and then connected to the differential comparison circuit through the measuring channel and the reference channel; a signal attenuation unit is provided in the measuring channel; The differential comparison circuit, the data acquisition unit, and the data processing unit are connected in sequence; The differential comparison circuit includes an instrumentation amplifier FX620, an adjustable resistor RP1, and a resistor R1; The positive input terminal of the instrument amplifier FX620 is connected to the measurement channel; the negative input terminal of the instrument amplifier FX620 is connected to the reference channel; Terminal 5 of the instrument amplifier FX620 is grounded; the resistor R1 and the adjustable resistor RP1 are connected in parallel and then bridged between terminals 8 and 1 of the instrument amplifier FX620.

2. The optical signal measurement system based on differential comparison and compensation of reference light and reference light as claimed in claim 1, characterized in that: The measurement channel and the reference channel both include a photoelectric conversion unit, a signal amplification unit, and a filtering circuit; The input end of the signal attenuation unit in the measurement channel is connected to the measurement light signal unit, and the output end is connected to the photoelectric conversion unit, the signal amplification unit, and the filter circuit of the measurement channel in sequence, and is connected to the positive input end of the instrument amplifier FX620 of the differential comparison circuit through the filter circuit; The input end of the photoelectric conversion unit in the reference channel is connected to the reference optical signal unit, and the output end is connected to the signal amplification unit and the filter circuit of the reference channel in sequence, and is connected to the negative input end of the instrument amplifier FX620 of the differential comparison circuit through the filter circuit.

3. The optical signal measurement system based on differential comparison and compensation of reference light and reference light as claimed in claim 2, characterized in that: The filter circuit adopts an RC filter circuit.

4. An optical signal measurement system based on differential comparison and compensation of reference light and reference light as claimed in claim 1, 2 or 3, characterized in that: The data acquisition unit adopts an AD conversion circuit.

5. The optical signal measurement system based on differential comparison and compensation of reference light and reference light as claimed in claim 1, 2 or 3, characterized in that: The data processing unit adopts a CPU processing chip.

6. An optical signal measurement system based on differential comparison and compensation of reference light and reference light as claimed in claim 1, 2 or 3, characterized in that: The signal attenuation unit uses a measuring medium to attenuate the measuring light signal through the measuring medium.

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