A compensation control method for zero drift of terahertz detector and its dedicated system

Abstract

The present invention provides a compensation control method for zero drift of a terahertz detector, which can solve the problem that the current zero drift obviously affects the detection accuracy of the terahertz detector. The method records the output level of the terahertz detector obtained in the initial zeroing operation as the reference zero level; controls the terahertz controller to perform a re-zeroing operation after each working time T, records the output level of the terahertz detector obtained by the re-zeroing operation as the adjusted zero level, calculates the level difference between the adjusted zero level and the reference zero level and records the level difference as the zero drift value, controls the terahertz detector to enter the detection work with a duration of T again, and in this process, always inputs a compensation level that is equal to and opposite to the zero drift value to the output rear stage of the terahertz detector, so that the compensation level always offsets the zero drift value, so that the terahertz detector still uses the reference zero level as the signal detection reference to detect the terahertz radiation signal.

Description

Technical Field

[0001] The present invention relates to the technical field of millimeter-wave / terahertz detection, and particularly to a compensation control method for zero-position drift of a terahertz detector and a dedicated system therefor. Background Art

[0002] Before detecting a target, a terahertz detector usually needs to perform a zero-adjustment operation first. The zero-adjustment operation is to block the antenna of the detector with a shielding material whose temperature is equal to the ambient temperature and use this as the zero-input state of the detector. At this time, a voltmeter is used to detect that the output signal of the detector is a certain constant level, and this constant level value is the zero-position level of the detector, as Figure 1 shown; after the zero-adjustment is completed, the blackbody material is removed, and the antenna of the terahertz detector is directed at the detection target to detect the terahertz radiation signal. At this time, the input is not zero, and the output level of the detector is detected by a voltmeter, as shown in Figure 2 , and at this time, the detected level deviates from the zero-position level. In practical applications, an analog-to-digital converter (AD converter) is used at the rear stage of the terahertz detector to sample the detected level and convert it into a digital signal, and then a micro-control unit (MCU) reads and converts the digital signal to obtain the input quantity of the terahertz detector. In this way, a typical detector sampling conversion and reading device is formed, as Figure 3 shown.

[0003] However, similar to most analog devices, the zero-position level of the detector in the non-ideal state will deviate from the zero-position level in the initial state as the working time increases due to factors such as the internal circuit heating of the detector or external temperature disturbances; in order to ensure the detection accuracy of the terahertz detector, the terahertz detector often needs to perform a zero-adjustment operation again after working for a period of time. However, in the re-zero-adjustment operation, the terahertz detector often cannot output the zero-position level in the initial state, but outputs a new zero-position level, that is, there is a difference between the front and rear zero-position levels, and this difference is the zero-position drift of the terahertz detector, as Figure 4 shown. During the long-term use of the terahertz detector, multiple zero-adjustment operations will cause the zero-position drift amount to continuously accumulate. When the continuously accumulated zero-position drift amount approaches the upper and lower limits of the sampling range of the analog-to-digital converter (AD converter), it may cause the output level corresponding to the actual detection target to exceed the sampling range of the analog-to-digital converter (AD converter), that is, AD input overflow, resulting in measurement value distortion (see Figure 5 ). Generally speaking, the sampling range of the analog-to-digital converter (AD converter) is matched with the maximum level change amount output by the terahertz detector. If a larger sampling range analog-to-digital converter is used to avoid AD input overflow, a large amount of the sampling range of the analog-to-digital converter (AD converter) will be wasted, that is, it is equivalent to reducing the dynamic range of the terahertz detector and resulting in a decrease in measurement accuracy, as Figure 6as shown

[0004] In summary, the zero - point drift of the terahertz detector will significantly affect the measured value of the detector; under the current technical conditions, the zero - point drift of the terahertz detector cannot be avoided. Therefore, how to overcome the influence of zero - point drift on the detection accuracy of the terahertz detector has become an urgent problem to be solved in this field. Summary of the Invention

[0005] In view of the above problems, the present invention provides a compensation control method for zero - point drift of a terahertz detector, which can solve the problem that the current zero - point drift significantly affects the detection accuracy of the terahertz detector; for this purpose, the present invention also provides a dedicated system.

[0006] A compensation control method for zero - point drift of a terahertz detector, characterized in that it successively includes the following steps

[0007] Step S100, perform an initial zero - adjustment operation on the terahertz detector before it starts to work, and record the output level of the terahertz detector obtained in the initial zero - adjustment operation as the reference zero - point level;

[0008] Step S200, the terahertz detector uses the reference zero - point level as the signal detection reference to detect the terahertz radiation signal for a duration of T;

[0009] Step S300, perform a re - zero - adjustment operation on the terahertz detector, and record the output level of the terahertz detector obtained in the re - zero - adjustment operation as the adjusted zero - point level;

[0010] Step S400, calculate the level difference between the adjusted zero - point level obtained in step 300 and the reference zero - point level, and record this level difference as the zero - point drift value;

[0011] Step S500, control the terahertz detector to enter the detection work with a duration of T again, and always input a compensation level equal in value and opposite in direction to the zero - point drift value to the post - stage of the output of the terahertz detector during the detection work with a duration of T, so that the compensation level and the zero - point drift value always cancel each other out during the detection work with a duration of T, so that the terahertz detector still uses the reference zero - point level as the signal detection reference to detect the terahertz radiation signal;

[0012] Then successively loop to execute step S300, step S400, and step S500.

[0013] Furthermore, the zero - adjustment operation includes the following steps

[0014] Step S610, use a shielding material with a temperature equal to the ambient temperature to cover the antenna of the terahertz detector;

[0015] Step S620: The analog-to-digital converter collects the output level of the terahertz detector in this state, converts the output level from the analog signal mode to the digital signal mode, and then transmits it to the microprocessor for storage.

[0016] Step S630: Then, remove the shielding material that blocks the antenna of the terahertz detector.

[0017] Further, in steps S400 and S500, the microprocessor calculates the zero drift value and the compensation level, and transmits the compensation level to the digital-to-analog converter. The digital-to-analog converter converts the compensation level from the digital signal mode to the analog signal mode and then inputs it to the output stage after the terahertz detector.

[0018] Further, the shielding material has a first position and a second position, and an electric control actuator controls the shielding material to move between the first position and the second position. When performing a zero adjustment operation on the terahertz detector, the electric control actuator controls the shielding material to move to the first position, at which time the shielding material can completely block the antenna of the terahertz detector. When the terahertz detector is to perform the detection work of the terahertz radiation signal with a duration of T, the electric control actuator controls the shielding material to move to the second position, at which time the shielding material cannot block the antenna of the terahertz detector.

[0019] Even further, the shielding material sends a position status signal to the microprocessor through a signal switch. When the shielding material moves to the first position, the signal switch is disconnected. After receiving the disconnection signal of the signal switch, the microprocessor controls the execution of step S620 and step S400. When the shielding material moves to the second position, the signal switch is closed. After receiving the closing signal of the signal switch, the microprocessor controls the execution of step S500.

[0020] Even further, the shielding material controls the disconnection or closing of the signal switch through a mechanical linkage device.

[0021] Even further, the shielding material is a blackbody material.

[0022] A dedicated system for the compensation control method of the zero drift of a terahertz detector, characterized in that it includes

[0023] A terahertz detector for detecting terahertz radiation signals;

[0024] A shielding material for blocking the antenna of the terahertz detector when performing a zero adjustment operation on the terahertz detector;

[0025] An analog-to-digital converter for collecting the output level of the terahertz detector and converting the collected output level from the analog signal mode to the digital signal mode;

[0026] A microprocessor, configured to collect and store the output level of a terahertz detector that has been converted into a digital signal mode and output by the analog-to-digital converter, and calculate and store the zero drift value and the compensation level that is equal in value and opposite in direction to the zero drift value;

[0027] A digital-to-analog converter, configured to convert the compensation level from a digital signal mode to an analog signal mode and input the compensation level converted to the analog signal mode to the post-stage output of the terahertz detector;

[0028] A power supply, configured to provide operating voltages for the terahertz detector and the microprocessor;

[0029] The analog-to-digital converter, the digital-to-analog converter and the microprocessor are respectively connected by a communication bus for signal connection, and the post-stage output of the terahertz detector, the input terminal of the analog-to-digital converter and the output terminal of the digital-to-analog converter are electrically connected.

[0030] Further, it further includes an electric control actuator for controlling the movement of the shielding material, and the electric control actuator and the microprocessor are connected by a communication bus for signal connection.

[0031] Furthermore, the shielding material is further connected to a signal switch through a mechanical linkage device, the output terminal of the microprocessor is electrically connected to the signal switch, and the power supply provides an operating voltage for the signal switch.

[0032] The beneficial effect of a compensation control method for zero drift of a terahertz detector according to the present invention is that: by inputting a compensation level equal in value and opposite in direction to the zero drift value of the terahertz detector to the post-stage output of the terahertz detector, the zero drift value can be completely offset by the compensation level, so that the terahertz detector can always use the reference zero level obtained by the initial zero adjustment as the signal detection reference to detect terahertz signals, ensuring that the input voltage of the analog-to-digital converter at the post-stage output of the terahertz detector will not overflow due to the superposition of multiple zero drifts, and ensuring the accuracy and stability of the detection structure of the terahertz detector. Description of the Drawings

[0033] Figure 1 It is a schematic diagram of the principle of zero adjustment operation for a terahertz detector in the art;

[0034] Figure 2 It is a schematic diagram of the principle of detecting terahertz radiation signals of a target using a terahertz detector in the art;

[0035] Figure 3 It is a schematic diagram of the sampling conversion and reading principle of a typical existing terahertz detector in the art;

[0036] Figure 4 It is a schematic diagram of the zero - position drift principle of a terahertz detector in the art;

[0037] Figure 5 It is a schematic diagram of AD input overflow during the sampling conversion and reading process of an existing typical terahertz detector in the art;

[0038] Figure 6 It is a schematic diagram of a large amount of the sampling range of the analog - to - digital converter being wasted after using an analog - to - digital converter with a large sampling range during the sampling conversion and reading process of an existing typical terahertz detector in the art;

[0039] Figure 7 It is a schematic diagram of the principle of the compensation control method of the present invention;

[0040] Figure 8 It is a schematic diagram of the principle of the dedicated system composition of the compensation method of the present invention;

[0041] Figure 9 It is a schematic diagram of system control when the shielding material reaches the first position in the present invention;

[0042] Figure 10 It is a schematic diagram of system control when the shielding material reaches the second position in the present invention. Detailed implementation mode

[0043] A compensation control method for zero - position drift of a terahertz detector according to the present invention sequentially includes the following steps:

[0044] Step S100, perform an initial zero - adjustment operation on the terahertz detector before it starts working, and record the output level of the terahertz detector obtained in the initial zero - adjustment operation as the reference zero - position level;

[0045] Step S200, the terahertz detector uses the reference zero - position level as the signal detection reference to detect terahertz radiation signals for a duration of T;

[0046] Step S300, perform a re - zero - adjustment operation on the terahertz detector, and record the output level of the terahertz detector obtained in the re - zero - adjustment operation as the adjusted zero - position level;

[0047] Step S400, calculate the level difference between the adjusted zero - position level obtained in step 300 and the reference zero - position level, and record this level difference as the zero - position drift value;

[0048] Step S500: Control the terahertz detector to enter the detection operation for a duration of T again, and during the detection operation with the duration of T, always input a compensation level equal in value and opposite in direction to the zero position drift value to the output stage after the terahertz detector, so that during the detection operation with the duration of T, the compensation level always cancels out the zero position drift value, and thus the terahertz detector still uses the reference zero level as the signal detection reference to perform the terahertz radiation signal detection operation, as shown in Figure 7 ;

[0049] Then sequentially and circularly execute Step S300, Step S400, and Step S500.

[0050] The zero adjustment operation includes the following steps,

[0051] Step S610: Use a shielding material with a temperature equal to the ambient temperature to shield the antenna of the terahertz detector;

[0052] Step S620: The analog-to-digital converter collects the output level of the terahertz detector in this state, converts the output level from the analog signal mode to the digital signal mode, and then transmits it to the microprocessor for storage;

[0053] Step S630: Then remove the shielding of the antenna of the terahertz detector by the shielding material.

[0054] When performing the initial zero adjustment operation before the terahertz detector works, the output level collected by the analog-to-digital converter in Step S620 is the reference zero level; and when the zero adjustment operation is the readjustment during the terahertz detection operation, the output level collected by the analog-to-digital converter in Step S620 is the adjusted zero level. The analog-to-digital converter converts the adjusted zero level from the analog signal to the digital signal and then transmits it to the microprocessor. The microprocessor calculates the level difference between the adjusted zero level and the stored reference zero level, and this level difference is the zero position drift value of this readjustment.

[0055] Moreover, in Steps S400 and S500, the microprocessor calculates the zero position drift value and the compensation level, and transmits the compensation level to the digital-to-analog converter. The digital-to-analog converter converts the compensation level from the digital signal mode to the analog signal mode and then inputs it to the output stage after the terahertz detector.

[0056] As a preferred technical solution of the method of the present invention, the shielding material has a first position and a second position, as shown in Figure 9 and Figure 10, an electric control actuator controls the movement of the shielding material between a first position and a second position; when zeroing the terahertz detector, the electric control actuator controls the shielding material to move to the first position, at which time the shielding material can completely block the antenna of the terahertz detector; when the terahertz detector is to detect terahertz radiation signals with a duration of T, the electric control actuator controls the shielding material to move to the second position, at which time the shielding material cannot block the antenna of the terahertz detector.

[0057] As a further preferred technical solution of the method of the present invention, the shielding material sends a position status signal to the microprocessor through a signal switch; when the shielding material moves to the first position, the signal switch is disconnected, and after receiving the disconnection signal of the signal switch, the microprocessor controls the execution of step S620 and step S400; when the shielding material moves to the second position, the signal switch is closed, and after receiving the closing signal of the signal switch, the microprocessor controls the execution of step S500.

[0058] As a further preferred technical solution of the method of the present invention, the shielding material controls the opening / closing of the signal switch through a mechanical linkage device. When the shielding material moves to the first position, the shielding material drives the signal switch to disconnect through the mechanical linkage device. When the shielding material moves to the second position, the shielding material drives the signal switch to close through the mechanical linkage device.

[0059] In the method of the present invention, the shielding material is a blackbody material.

[0060] See Figure 8 , a dedicated system for the compensation control method of zero position drift of a terahertz detector according to the present invention, which includes

[0061] A terahertz detector 10 for detecting terahertz radiation signals;

[0062] A shielding material 20 for blocking the antenna of the terahertz detector during zeroing the terahertz detector, and a blackbody material is used in the present invention;

[0063] An analog-to-digital converter 30 for collecting the output level of the terahertz detector and converting the collected output level from an analog signal mode to a digital signal mode;

[0064] A microprocessor 40 for collecting and storing the output level of the terahertz detector that has been converted to the digital signal mode output by the analog-to-digital converter, and calculating and storing the zero position drift value and the compensation level equal in value and opposite in direction to the zero position drift value;

[0065] A digital-to-analog converter 50 for converting the compensation level from the digital signal mode to the analog signal mode and inputting the compensation level converted to the analog signal mode to the output stage behind the output of the terahertz detector;

[0066] A power supply 60 for providing operating voltages for the terahertz detector and the microprocessor;

[0067] The analog-to-digital converter 30, the digital-to-analog converter 50 and the microprocessor 40 are respectively connected by a communication bus for signal connection. The output stage of the terahertz detector 10, the input end of the analog-to-digital converter 30, and the output end of the digital-to-analog converter 50 are electrically connected.

[0068] See Figure 9 and Figure 10 , and it further includes an electric control actuator 70 for controlling the movement of the shielding material 20. The electric control actuator 70 and the microprocessor 40 are connected by a communication bus for signal connection; the shielding material 20 is also connected to a signal switch 90 through a mechanical linkage device 80. The input end of the microprocessor 40 is electrically connected to the signal switch 90, and the power supply 60 provides an operating voltage for the signal switch.

[0069] The working process of the special system of the present invention will be specifically described below with reference to the accompanying drawings:

[0070] See Figure 9 , when performing the zero adjustment operation of the terahertz detector 10, the microprocessor 40 issues an action instruction to the electric control actuator 70. The electric control actuator 70 controls the shielding material 20 to move to one side of the antenna of the terahertz detector 10 so that the antenna of the terahertz detector 10 is completely blocked by the shielding material 20 (i.e., when moving to the first position). While the shielding material 20 is moving, it disconnects the signal switch 90 through the mechanical linkage device 80. After receiving the signal that the signal switch 90 is disconnected, the microprocessor 40 controls the analog-to-digital converter 30 to collect the output level signal of the terahertz detector 10 at this time, converts the output level from an analog signal to a digital signal, and transmits it to the microprocessor 40. After receiving the output level converted by the analog-to-digital converter 30, if this zero adjustment operation is the initial zero adjustment before the terahertz detector 10 officially performs detection work, the microprocessor 40 marks this output level as the reference zero level and stores it; if this zero adjustment operation is the re-zero adjustment operation during the detection work of the terahertz detector 10, the microprocessor 40 marks this output level as the adjusted zero level, calculates the level difference between the adjusted zero level and the reference zero level recorded and stored during the initial zero adjustment, marks this level difference as the zero drift value of this re-zero adjustment operation, and then marks and stores this zero drift value as the compensation level according to the principle of equal value and reverse direction; then the microprocessor 40 outputs a zero level to the digital-to-analog converter 50, and the digital-to-analog converter 50 outputs a zero level to the subsequent stage of the terahertz detector 10.

[0071] See Figure 10, after a zero adjustment operation of the terahertz detector 10 is completed, the microprocessor 40 sends an action instruction to the electric control actuator 70. The electric control actuator 70 controls the movement of the shielding material 20 so that the shielding material 20 gradually moves away from the antenna of the terahertz detector 10. When the shielding material 20 moves to the second position, the mechanical linkage device 80 simultaneously drives the signal switch 90 to close, and the terahertz controller 10 enters the normal detection work. After receiving the closing signal of the signal switch 90, the microprocessor 40 always maintains outputting the compensation level marked and stored after the previous zero adjustment operation to the digital-to-analog converter 50. The digital-to-analog converter 50 converts the compensation level from a digital signal into an analog signal and then transports it to the subsequent stage of the terahertz detector 10 in the normal detection working state and adds it to the detection level output by the terahertz detector 10 at this time. Since the compensation level and the zero level drift value are equal in value and opposite in direction, the compensation for the zero level drift is realized, and the terahertz detector 10 always uses the reference zero level as the signal detection reference to detect the terahertz radiation signal.

[0072] The above has detailed the specific implementation of the present invention, but the content is only the preferred implementation of the present invention and cannot be considered as being used to limit the implementation scope of the present invention. All equivalent changes and improvements made according to the application scope of the present invention should still fall within the patent coverage scope of the present invention.

Claims

1. A compensation control method for zero drift of a terahertz detector, characterized in that: It includes the following steps in sequence: Step S100, performing an initial zeroing operation on the terahertz detector before the terahertz detector starts working, and recording the output level of the terahertz detector obtained in the initial zeroing operation as a reference zero level; Step S200, the terahertz detector detects the terahertz radiation signal with a duration of T using the reference zero level as a signal detection reference; Step S300, performing a re-zeroing operation on the terahertz detector, and recording the output level of the terahertz detector obtained by the re-zeroing operation as an adjusted zero level; Step S400, calculating the level difference between the adjusted zero level obtained in step 300 and the reference zero level and recording the level difference as a zero drift value; Step S500, controlling the terahertz detector to enter a detection operation with a duration of T again, and always inputting a compensation level that is equal to and opposite to the zero drift value to the output back stage of the terahertz detector during the detection operation with a duration of T, so that during the detection operation with a duration of T, the compensation level always offsets the zero drift value, so that the terahertz detector still uses the reference zero level as a signal detection reference to detect the terahertz radiation signal; Then, the steps S300, S400, and S500 are executed in a loop in sequence; The zeroing operation comprises the following steps: Step S610, shielding the antenna of the terahertz detector with a shielding material having a temperature equal to the ambient temperature; Step S620, the analog-to-digital converter collects the output level of the terahertz detector in this state, converts the output level from an analog signal mode to a digital signal mode, and transmits the digital signal mode to the microprocessor for storage; Step S630, then remove the shielding material from shielding the antenna of the terahertz detector.

2. The compensation control method for zero drift of a terahertz detector according to claim 1, characterized in that: In steps S400 and S500, the microprocessor calculates the zero drift value and the compensation level, and transmits the compensation level to the digital-to-analog converter, which converts the compensation level from a digital signal mode to an analog signal mode and inputs it into the output stage after the terahertz detector.

3. The compensation control method for zero drift of a terahertz detector according to claim 2, characterized in that: The shielding material has a first position and a second position, and an electrically-controlled actuator controls the shielding material to move between the first position and the second position; when the terahertz detector is to be zeroed, the electrically-controlled actuator controls the shielding material to move to the first position, at which time the shielding material can completely block the antenna of the terahertz detector; when the terahertz detector is to detect a terahertz radiation signal for a duration of T, the electrically-controlled actuator controls the shielding material to move to the second position, at which time the shielding material cannot block the antenna of the terahertz detector.

4. The compensation control method for zero drift of a terahertz detector according to claim 3, characterized in that: The shielding material sends a position status signal to the microprocessor through a signal switch; when the shielding material moves to the first position, the signal switch is disconnected, and the microprocessor controls the execution of steps S620 and S400 after receiving the disconnection signal of the signal switch; when the shielding material moves to the second position, the signal switch is closed, and the microprocessor controls the execution of step S500 after receiving the closing signal of the signal switch.

5. The compensation control method for zero drift of a terahertz detector according to claim 4, characterized in that: The shielding material controls the opening or closing of the signal switch through a mechanical linkage device.

6. A method for compensating and controlling zero drift of a terahertz detector according to any one of claims 1 to 5, characterized in that: The shielding material is a black body material.

7. A dedicated system for a compensation control method for a terahertz detector zero drift, characterized in that: It includes A terahertz detector, used to detect terahertz radiation signals; A shielding material used to shield the antenna of the terahertz detector when performing a zeroing operation on the terahertz detector; An analog-to-digital converter, used for collecting the output level of the terahertz detector and converting the collected output level from an analog signal mode to a digital signal mode; A microprocessor, used for collecting and storing the output level of the terahertz detector converted into a digital signal mode by the analog-to-digital converter, and calculating and storing a zero drift value and a compensation level which is equal to and opposite to the zero drift value; A digital-to-analog converter, used to convert the compensation level from a digital signal mode to an analog signal mode and input the compensation level converted into the analog signal mode to an output post-stage of the terahertz detector; A power supply, used to provide operating voltage for the terahertz detector and microprocessor; The analog-to-digital converter, the digital-to-analog converter and the microprocessor are respectively connected by signals via a communication bus, and the output rear stage of the terahertz detector, the input end of the analog-to-digital converter and the output end of the digital-to-analog converter are electrically connected.

8. The dedicated system for the compensation control method of the terahertz detector zero drift according to claim 7, characterized in that: It also includes an electric control actuator for controlling the movement of the shielding material. The electric control actuator is connected to the microprocessor by signals via a communication bus.

9. The dedicated system for the compensation control method of the terahertz detector zero drift according to claim 8, characterized in that: The shielding material is connected to a signal switch through a mechanical linkage device, the output end of the microprocessor is electrically connected to the signal switch, and the power supply provides a working voltage for the signal switch.

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