High-precision synchronous locking optical signal acquisition circuit for space

Abstract

The invention discloses a high-precision synchronous locking optical signal acquisition circuit for space, which belongs to the technical field of optical signal acquisition for space and comprises a signal conversion unit and an information processing unit. The signal conversion unit comprises M groups of photoelectric conversion circuits, each group of photoelectric conversion circuits comprises N photoelectric conversion circuits, and each photoelectric conversion circuit comprises a conversion circuit and a sampling holder; in each photoelectric conversion circuit, the output terminal of the conversion circuit is connected with the input terminal of the sampling holder; the output terminal of each photoelectric conversion circuit is connected with an N-path analog switch, and the output terminal of the N-path analog switch is connected with a differential circuit through a multi-path analog-to-digital converter; the information processing unit outputs address signals to the N paths of analog switches and outputs sampling holding signals to the sampling holder; the sampling holder carries out synchronous locking and impedance conversion on M * N paths of voltage signals and sends the signals to the N paths of analog switches, and N is smaller than the number of input paths of the multi-path analog-to-digital converter.

Description

Technical Field

[0001] The invention belongs to the technical field of space optical signal acquisition, and in particular relates to a space high-precision synchronous locking optical signal acquisition circuit. Background Art

[0002] As the application of optoelectronic payloads in space environments becomes increasingly widespread, the demand for optical signal acquisition circuits has become increasingly common and urgent. At present, in space environments, traditional optical signal acquisition circuits have the following main defects:

[0003] First, they have great difficulty in capturing weak light signals, which limits their application in certain specific environments;

[0004] Second, the synchronization time of these traditional optical signal acquisition circuits is relatively long. Usually, this time is greater than 10 microseconds, which is an obvious shortcoming in situations that require fast response.

[0005] Third, the acquisition accuracy of these acquisition circuits is not high, and its accuracy range is generally around 1%, which is a problem that cannot be ignored for application scenarios that require high-precision measurement;

[0006] Fourth, these traditional optical signal acquisition circuits have poor anti-interference capabilities, which makes them susceptible to interference in complex electromagnetic environments, affecting the accurate acquisition of signals;

[0007] Fifth, these optical signal acquisition circuits have weak scalability, which limits their application in systems that require flexible configuration and upgrade. Summary of the invention

[0008] The purpose of the present invention is to provide a high-precision synchronous locked optical signal acquisition circuit for space use, which is suitable for data acquisition of optical signals. It can not only capture weak optical signals, but also has the advantages of short synchronization time, high acquisition accuracy, strong anti-interference ability and strong scalability.

[0009] To achieve the above object, the present invention provides the following technical solutions:

[0010] A high-precision synchronous locking optical signal acquisition circuit for space use, comprising a signal conversion unit and an information processing unit; wherein:

[0011] The signal conversion unit includes M groups of photoelectric conversion circuits, each group of photoelectric conversion circuits includes N photoelectric conversion circuits, and each photoelectric conversion circuit includes a conversion circuit and a sample-and-hold device; in each photoelectric conversion circuit, an output terminal of the conversion circuit is connected to an input terminal of the sample-and-hold device; an output terminal of each photoelectric conversion circuit is connected to an N-way analog switch, and an output terminal of the N-way analog switch is connected to a differential circuit via a multi-way analog-to-digital converter;

[0012] The information processing unit exchanges data with N analog switches and each sample holder respectively, outputs address signals to the N analog switches, and outputs sample hold signals to the sample holders; the sample holders perform synchronous locking and impedance transformation on M×N voltage signals, and send the signals to the N analog switches, where N is less than the number of input channels of the multi-channel analog-to-digital converter; M and N are both natural numbers greater than 1.

[0013] Preferably, the conversion circuit includes a photodiode that converts an optical signal into a current signal, the positive electrode of the photodiode is connected to a reference power supply; the negative electrode of the photodiode is grounded through a capacitor; the positive electrode of the photodiode is grounded through resistor No. 1 and resistor No. 2, and the positive electrode of the photodiode is connected to the negative electrode of the photodiode through resistor No. 1.

[0014] Preferably, the cathode of the photodiode is connected to the input terminal of the sample and hold device.

[0015] Preferably, the voltage V of the sample and hold device out for:

[0016]

[0017] Where: V ref is the voltage of the reference power supply; R1 is the resistance value of resistor No. 1; R2 is the resistance value of resistor No. 2; R1=R2=Vref kΩ / V; I is the output current of the photodiode.

[0018] Preferably, the information processing unit includes a differential circuit, a processor and a memory.

[0019] Preferably, the processor is one of FPGA, DSP, and MCU.

[0020] Preferably, the information processing unit exchanges information with the communication terminal via a serial bus, receives control instructions, and transmits the collected data to the communication terminal in a certain format.

[0021] Preferably, the differential circuit is RS422 or LVDS.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The present invention selects appropriate circuit parameters, namely, R1=R2=Vref kΩ / V, and the dark current of the photoelectric sensor only needs to be at the nA level to capture the weak photocurrent signal of the uA level, and the requirements for the photoelectric sensor are not high;

[0024] The present invention synchronizes and locks multiple optical signals through a sample-and-hold device, and has the ability to synchronously capture signals at high speed (microsecond level);

[0025] The voltage collected by the present invention is only related to the reference bias voltage and the voltage divider resistor, and the reference voltage can offset interference by digital differential mode. The collection accuracy is only related to the voltage divider resistor, and the collection accuracy is high (the collection accuracy can reach 0.1%).

[0026] The present invention converts the photocurrent into voltage by using a resistor voltage divider, and the resistor form is simple and reliable;

[0027] The invention adopts differential signals for data transmission and communication, and has strong anti-interference ability;

[0028] The present invention separates signal conversion and information processing, and has strong independence; M×N signal paths can be expanded through analog switches, and has strong scalability. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A circuit block diagram of a preferred embodiment of the present invention;

[0030] Figure 2 It is a circuit diagram of a sub-circuit in a preferred embodiment of the present invention, used to show the circuit relationship between the conversion circuit and the sample-and-hold device. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] See also Figure 1 and Figure 2 As shown, a high-precision synchronous locking optical signal acquisition circuit for space use mainly includes two parts: a signal conversion unit and an information processing unit; wherein:

[0033] The signal conversion unit realizes signal conversion and transmission through conversion circuit, sample and hold, analog switch, analog-to-digital converter and differential circuit: light->current->voltage->multiplexed voltage->digital signal->digital differential signal.

[0034] The conversion circuit and the sample-and-hold circuit 1-M×N are photoelectric conversion circuits, such as Figure 2 As shown, the photodiode converts the light signal into a current signal. The current signal generates a voltage signal proportional to the current signal after flowing through resistors R1 and R2. The sample-and-hold device performs synchronous locking and impedance transformation on the M×N voltage signals and sends them to N analog switches. The outputs of the N analog switches are connected to a multi-channel serial analog-to-digital converter. N should be less than the number of input channels of the analog-to-digital converter.

[0035] The signal conversion unit includes M groups of photoelectric conversion circuits, each group of photoelectric conversion circuits includes N photoelectric conversion circuits, and each photoelectric conversion circuit includes a conversion circuit and a sample-and-hold device; in each photoelectric conversion circuit, an output terminal of the conversion circuit is connected to an input terminal of the sample-and-hold device; an output terminal of each photoelectric conversion circuit is connected to an N-way analog switch, and an output terminal of the N-way analog switch is connected to a differential circuit via a multi-way analog-to-digital converter;

[0036] The information processing unit can use various processors such as FPGA, DSP, MCU, etc. to output address signals, sampling and holding signals, and serial bus control signals. In order to improve the anti-interference performance of the control signal, a differential circuit is used to convert the single-ended signal into a differential signal. According to the characteristics of the interference source and the interference path, the differential circuit can use RS422, LVDS or other level standards.

[0037] The information processing unit exchanges information with the communication terminal through the serial bus, receives control instructions, and transmits the collected data to the communication terminal in a certain format.

[0038] The information processing unit exchanges data with N analog switches and each sample holder respectively, outputs address signals to the N analog switches, and outputs sample hold signals to the sample holders; the sample holders perform synchronous locking and impedance transformation on M×N voltage signals, and send the signals to the N analog switches, where N is less than the number of input channels of the multi-channel analog-to-digital converter; M and N are natural numbers greater than 1.

[0039] As attached Figure 2 As shown in the figure, the photoelectric conversion circuit converts the current signal output by the photoelectric tube into a voltage signal, which is then transmitted to the analog-to-digital converter through the sample-and-hold device. According to the theoretical derivation, the voltage V out for:

[0040]

[0041] Where: V ref is the voltage of the reference power supply; R1 is the resistance value of resistor No. 1; R2 is the resistance value of resistor No. 2; R1=R2=Vref kΩ / V; I is I is the output current of the photodiode.

[0042] The transformed voltage signal is held by a sample-and-hold device, and a control signal is used to synchronously hold the M×N sample-and-hold devices, so that the circuit can synchronously collect all analog quantities.

[0043] To expand M×N signals, use the following Figure 1The topology shown in the figure is used to expand multi-channel signals. Multi-channel serial analog-to-digital conversion is used to realize digital quantization of M×N signals converted by M analog switches. In order to improve the independence of circuit functions, signal acquisition and information processing are divided into two independent units. In order to improve the reliability of information transmission between the two independent units, differential or single-ended transmission of data and control signals can be selected according to the actual line length of the two units. The information processing unit can process the collected information and send it to the communication terminal through the differential serial bus.

[0044] The conversion circuit includes a photosensitive diode that converts an optical signal into a current signal, wherein the positive electrode of the photosensitive diode is connected to a reference power supply; the negative electrode of the photosensitive diode is grounded through a capacitor; the positive electrode of the photosensitive diode is grounded through a No. 1 resistor and a No. 2 resistor, and the positive electrode of the photosensitive diode is connected to the negative electrode of the photosensitive diode through the No. 1 resistor.

[0045] The cathode of the photodiode is connected to the input terminal of the sample-and-hold device.

[0046] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems) and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor or other programmable data processing device to generate a program, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A way to specify functions in one or more boxes.

[0047] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0048] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0049] In the drawings of the embodiments disclosed in the present invention, only the structures involved in the embodiments disclosed in the present invention are involved, and other structures can refer to the general design. In the absence of conflict, the same embodiment and different embodiments of the present invention can be combined with each other.

[0050] The flowcharts shown in the accompanying drawings are only examples and do not necessarily include all the contents and operations / steps, nor must they be executed in the order described. For example, some operations / steps may also be decomposed, combined or partially merged, so the actual execution order may change according to actual conditions.

[0051] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A high-precision synchronous locking optical signal acquisition circuit for space, characterized in that: It includes a signal conversion unit and an information processing unit; wherein: The signal conversion unit includes M groups of photoelectric conversion circuits, each group of photoelectric conversion circuits includes N photoelectric conversion circuits, and each photoelectric conversion circuit includes a conversion circuit and a sample-and-hold device; in each photoelectric conversion circuit, an output terminal of the conversion circuit is connected to an input terminal of the sample-and-hold device; an output terminal of each photoelectric conversion circuit is connected to an N-way analog switch, and an output terminal of the N-way analog switch is connected to a differential circuit via a multi-way analog-to-digital converter; The information processing unit exchanges data with N analog switches and each sample holder respectively, outputs address signals to the N analog switches, and outputs sample hold signals to the sample holders; the sample holders perform synchronous locking and impedance transformation on M×N voltage signals, and send the signals to the N analog switches, where N is less than the number of input channels of the multi-channel analog-to-digital converter; M and N are both natural numbers greater than 1.

2. The high-precision synchronous locking optical signal acquisition circuit for space use according to claim 1, characterized in that: The conversion circuit includes a photosensitive diode that converts an optical signal into a current signal, wherein the positive electrode of the photosensitive diode is connected to a reference power supply; the negative electrode of the photosensitive diode is grounded through a capacitor; the positive electrode of the photosensitive diode is grounded through a No. 1 resistor and a No. 2 resistor, and the positive electrode of the photosensitive diode is connected to the negative electrode of the photosensitive diode through the No. 1 resistor.

3. The high-precision synchronous locking optical signal acquisition circuit for space use according to claim 2, characterized in that: The cathode of the photodiode is connected to the input terminal of the sample-and-hold device.

4. The high-precision synchronous locking optical signal acquisition circuit for space use according to claim 3, characterized in that: The voltage V of the sample-and-hold out for: Where: V ref is the voltage of the reference power supply; R1 is the resistance value of resistor No. 1; R2 is the resistance value of resistor No. 2; I is the output current of the photodiode.

5. The high-precision synchronous locking optical signal acquisition circuit for space use according to claim 1, characterized in that: The information processing unit includes a differential circuit, a processor and a memory.

6. The high-precision synchronous locking optical signal acquisition circuit for space use according to claim 5, characterized in that: The processor is one of FPGA, DSP and MCU.

7. The high-precision synchronous locking optical signal acquisition circuit for space use according to claim 1, characterized in that: The information processing unit exchanges information with the communication terminal via a serial bus, receives control instructions, and transmits the collected data to the communication terminal in a certain format.

8. The high-precision synchronous locking optical signal acquisition circuit for space use according to claim 1, characterized in that: The differential circuit is RS422 or LVDS.

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