Radio frequency microwave power level control device with temperature compensation

Abstract

A radio frequency microwave power level control device with temperature compensation comprises a sampler, a power level preset circuit, a digital processing circuit and a power level control circuit. The sampler comprises a power measurement thermistor, a temperature compensation thermistor, a heating resistor and a temperature acquisition resistor which are independently connected in parallel; the power measurement thermistor, the temperature compensation thermistor, the heating resistor and the temperature acquisition resistor are respectively connected with the digital processing circuit; the other end of the digital processing circuit is connected with the power level control circuit; three standard resistors of the power level preset circuit and the power measurement thermistor form a Wheatstone bridge, and then the Wheatstone bridge is connected with the digital processing circuit. The other end is connected with the power level control circuit; the whole device is electrically connected to form a complete closed loop. According to the utility model, by adding a temperature compensation function, errors caused by temperature drift of the sampler are reduced, and the precision of radio frequency microwave power level control is improved.

Description

Technical Field

[0001] The invention relates to the technical field of radio frequency microwave power level control, and in particular to a radio frequency microwave power level control device with temperature compensation. Background Art

[0002] With the widespread application of RF microwave technology, it is necessary to accurately control the RF microwave output power, especially in medium and high power RF microwave systems. Due to the use of RF microwave power amplifiers, the output power will decrease with the increase of signal frequency and amplifier temperature. The use of RF microwave power level control devices can control the output power and improve the output accuracy.

[0003] One of the factors that affects the output power control accuracy of the RF microwave power level control device is the sampler. The sampler performs bypass measurement on the output power, and the sampler measurement value directly affects the judgment of the RF microwave power level control device on the output power deviation. The measurement of RF microwaves can be mainly divided into two types: diode detection and calorimetric. The detection sampler can perform fast measurement, but due to its working principle, it cannot be accurately calibrated and is not suitable for RF microwave power calibration system.

[0004] At present, the RF microwave power level control device adopts a single thermistor sampler and analog direct control. The main disadvantage is that the error caused by thermistor temperature drift will directly affect the power level control signal, thereby affecting the accuracy of the RF microwave output power.

[0005] Therefore, due to the limitations of existing technology, people cannot solve it. Summary of the invention

[0006] (I) Purpose of the invention: In order to solve the problems existing in the above-mentioned prior art, the purpose of the present invention is to provide a radio frequency microwave power level control device that can compensate for the temperature drift of the sampler.

[0007] (II) Technical solution: In order to solve the above technical problems, the present technical solution provides a radio frequency microwave power level control device with temperature compensation, including a sampler, a power level preset circuit, a digital processing circuit and a power level control circuit;

[0008] The sampler comprises a power measurement thermistor, a temperature compensation thermistor, a heating resistor and a temperature acquisition resistor which are independently connected in parallel; the power measurement thermistor, the temperature compensation thermistor, the heating resistor and the temperature acquisition resistor are respectively connected to the digital processing circuit; the other end of the digital processing circuit is connected to the power level control circuit;

[0009] The three standard resistors of the power level preset circuit and the power measurement thermistor form a Wheatstone bridge, which is then connected to the digital processing circuit; the other end is connected to the power level control circuit; the entire device is electrically connected to form a complete closed loop.

[0010] Wherein, the digital processing circuit includes a sampler temperature compensation conversion circuit, a sampler temperature control circuit, a first analog-to-digital conversion circuit, a second analog-to-digital conversion circuit, a third analog-to-digital conversion circuit, a fourth analog-to-digital conversion circuit and a processor;

[0011] The first analog-to-digital conversion circuit is connected to the standard resistor; the second analog-to-digital conversion circuit is connected to the power measurement thermistor; the third analog-to-digital conversion circuit is connected to the sampler temperature compensation conversion circuit, and then connected to the temperature compensation thermistor; the fourth analog-to-digital conversion circuit is connected to the sampler temperature control circuit, and then connected to the heating resistor and the temperature acquisition resistor.

[0012] Among them, the first analog-to-digital conversion circuit, the second analog-to-digital conversion circuit, the third analog-to-digital conversion circuit, and the fourth analog-to-digital conversion circuit are respectively connected in parallel, and the output ends are connected to the processor, and the temperature-compensated power is displayed by the processor.

[0013] Among them, the sampler temperature compensation conversion circuit is a self-balanced Wheatstone bridge, and the temperature compensation thermistor is connected to the self-balanced Wheatstone bridge in a four-wire method, connected to the third analog-to-digital conversion circuit, and the DC component of the sampler temperature compensation conversion circuit is selected through the third analog-to-digital conversion circuit.

[0014] Wherein, the temperature compensation thermistor, the bridge arm standard resistor, the first operational amplifier and the second operational amplifier form a self-balancing Wheatstone bridge;

[0015] The positive power supply terminal and the negative power supply terminal of the first operational amplifier are respectively connected to the positive and negative poles of the first power supply; the positive power supply terminal and the negative power supply terminal of the second operational amplifier are respectively connected to the positive and negative poles of the second power supply; the first power supply includes two batteries connected in series, and the second power supply includes two batteries connected in series.

[0016] Wherein, the temperature compensation thermistor is connected to the connection of two batteries of the first power supply of the first operational amplifier through a first connection line; the second connection line of the temperature compensation thermistor is connected to the connection of two batteries of the second power supply of the second operational amplifier; the temperature compensation thermistor is connected to the same-direction input terminal of the first operational amplifier through a third connection line, and the temperature compensation thermistor is connected to the same-direction input terminal of the second operational amplifier through a fourth connection line;

[0017] The fifth connecting line of the bridge arm standard resistor is connected to the inverting input terminal of the first operational amplifier, and the sixth connecting line of the bridge arm standard resistor is connected to the inverting input terminal of the second operational amplifier; the output terminal of the first operational amplifier is connected to the inverting input terminal of the first operational amplifier; and the output terminal of the second operational amplifier is connected to the inverting input terminal of the second operational amplifier.

[0018] Wherein, the power level preset circuit includes a power setting circuit, a steady-state zero adjustment circuit, an analog adder and a Wheatstone bridge;

[0019] The power setting circuit and the steady-state zeroing circuit are both connected to the in-phase input terminal of the analog adder, and the inverting input terminal of the analog adder is grounded; the output terminal of the analog adder is connected to a Wheatstone bridge composed of the power measurement thermistor and three standard resistors.

[0020] The Wheatstone bridge comprises three standard resistors and a sampler power measurement thermistor, which are respectively connected in series and in parallel as four arms of the Wheatstone bridge; one end of the power measurement thermistor away from the second analog-to-digital conversion circuit is grounded.

[0021] The first analog-to-digital conversion circuit is connected to one of the standard resistors, and one end of the standard resistor away from the first analog-to-digital conversion circuit is grounded.

[0022] Wherein, the power level control circuit includes a digital-to-analog conversion circuit, an analog subtractor and a PID control circuit;

[0023] The digital-to-analog conversion circuit is connected to the processor, and the other end is connected to the inverting input end of the analog subtractor. The output end of the analog subtractor is connected to the PID control circuit, and the PID control circuit feedback regulates the power of the radio frequency microwave.

[0024] (III) Beneficial effects: The RF microwave power level control device with temperature compensation of the present invention reduces the error introduced by the temperature drift of the sampler by adding the temperature compensation function, and improves the accuracy of RF microwave power level control. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural diagram of a radio frequency microwave power level control device with temperature compensation of the utility model;

[0026] Figure 2 The utility model discloses a temperature compensation thermistor Rt2 of a radio frequency microwave power level control device with temperature compensation, which is connected to a self-balancing Wheatstone bridge structure by a four-wire method. DETAILED DESCRIPTION

[0027] The present invention is further described in detail below in conjunction with preferred embodiments. More details are elaborated in the following description to facilitate a full understanding of the present invention. However, the present invention can obviously be implemented in a variety of other ways different from the description. Those skilled in the art can make similar generalizations and deductions based on actual application situations without violating the connotation of the present invention. Therefore, the protection scope of the present invention should not be limited by the content of this specific embodiment.

[0028] The accompanying drawings are schematic diagrams of embodiments of the present invention. It should be noted that the drawings are only examples and are not drawn to scale, and should not be used to limit the actual protection scope of the present invention.

[0029] RF microwave power level control device with temperature compensation, such as Figure 1 As shown, it includes a sampler 20, a power level preset circuit 10, a digital processing circuit 30 and a power level control circuit 40. The sampler 20 is connected to the power level preset circuit 10 and the digital processing circuit 30 respectively; the output ends of the power level preset circuit 10 and the digital processing circuit 30 are connected to the power level control circuit 40; the output end of the power level preset circuit 10 is also connected to the digital processing circuit. The entire device is electrically connected to form a complete closed loop, which effectively and accurately controls the output power of the radio frequency microwave.

[0030] The sampler 20 includes a power measurement thermistor Rt1, a temperature compensation thermistor Rt2, a heating resistor Rh and a temperature acquisition resistor Rm which are independently connected in parallel. The power measurement thermistor Rt1, the temperature compensation thermistor Rt2, the heating resistor Rh and the temperature acquisition resistor Rm are respectively connected to the digital processing circuit 30; the other end of the digital processing circuit 30 is connected to the power level control circuit 40.

[0031] The digital processing circuit 30 includes a sampler temperature compensation conversion circuit 130, a sampler temperature control circuit 140, a first analog-to-digital conversion circuit 80, a second analog-to-digital conversion circuit 90, a third analog-to-digital conversion circuit 100, a fourth analog-to-digital conversion circuit 110 and a processor 120. The first analog-to-digital conversion circuit 80 is connected to the standard resistor Rs. The second analog-to-digital conversion circuit 90 is connected to the power measurement thermistor Rt1. After the third analog-to-digital conversion circuit 100 is connected to the sampler temperature compensation conversion circuit 130, it is connected to the temperature compensation thermistor Rt2. The fourth analog-to-digital conversion circuit 110 is connected to the sampler temperature control circuit 140, and then connected to the heating resistor Rh and the temperature acquisition resistor Rm respectively. The first analog-to-digital conversion circuit 80, the second analog-to-digital conversion circuit 90, the third analog-to-digital conversion circuit 100, and the fourth analog-to-digital conversion circuit 110 are respectively connected in parallel, and the output ends of the first analog-to-digital conversion circuit 80, the second analog-to-digital conversion circuit 90, the third analog-to-digital conversion circuit 100, and the fourth analog-to-digital conversion circuit 110 are respectively connected to the processor 120, and the temperature-compensated power is displayed by the processor 120.

[0032] More preferably, the power measurement thermistor Rt1 is connected to the power level preset circuit 10 and forms a Wheatstone bridge with three standard resistors Rs. And the first analog-to-digital conversion circuit 80 is connected to one of the standard resistors Rs for measuring the voltage value of the standard resistor Rs. The second analog-to-digital conversion circuit 90 is connected to the power measurement thermistor Rt1 for measuring the voltage value of the power measurement thermistor Rt1. One end of the power measurement thermistor Rt1 away from the second analog-to-digital conversion circuit 90 is grounded; one end of the standard resistor Rs away from the first analog-to-digital conversion circuit 80 is also grounded. Figure 1 shown.

[0033] The temperature compensation thermistor Rt2 is connected to the sampler temperature compensation conversion circuit 130, and the other end of the sampler temperature compensation conversion circuit 130 is connected to the third analog-to-digital conversion circuit 100. The voltage of the temperature compensation thermistor Rt2 is obtained through the sampler temperature compensation conversion circuit 130, and the collected DC voltage component value of the temperature compensation thermistor Rt2 is output through the third analog-to-digital conversion circuit 100.

[0034] More preferably, the sampler temperature compensation conversion circuit 130 processes the coupled AC part and only collects the voltage component of the DC part of the temperature compensation thermistor Rt2 and outputs it to the processor for data processing and display.

[0035] The power measurement thermistor Rt1 and the temperature compensation thermistor Rt2 are both temperature-dependent resistors, and the two constitute a dual-thermistor radio frequency microwave power sampling structure with a temperature compensation function.

[0036] The sampler temperature compensation conversion circuit 130 is a self-balancing Wheatstone bridge, and uses the characteristic of equal voltage at the input end of the operational amplifier to replace the resistance of the two opposite bridge arms on the original bridge, so that the temperature compensation thermistor Rt2 is connected to the bridge in a four-wire method. After the bridge is balanced, the voltage of the temperature compensation thermistor Rt2 on the opposite bridge arm to the Rcs standard resistor is the voltage value Vc of the temperature compensation thermistor Rt2; the bridge arms of the self-balancing Wheatstone bridge isolate the input end and the output end of the sampler temperature compensation conversion circuit 130 from each other.

[0037] like Figure 2 As shown, the temperature compensation thermistor Rt2, the bridge arm standard resistor Rcs, the first operational amplifier B50 and the second operational amplifier B60 form a self-balanced Wheatstone bridge. And the temperature compensation thermistor Rt2, the bridge arm standard resistor Rcs, the first operational amplifier B50 and the second operational amplifier B60 respectively serve as the four arms of the self-balanced Wheatstone bridge. The positive power supply terminal and the negative power supply terminal of the first operational amplifier B50 are respectively connected to the positive and negative electrodes of the first power supply B70. The positive power supply terminal and the negative power supply terminal of the second operational amplifier B60 are respectively connected to the positive and negative electrodes of the second power supply B80.

[0038] The first power supply B70 includes two batteries connected in series, and the temperature compensation thermistor Rt2 is connected to the connection of the two batteries of the first power supply B70 of the first operational amplifier B50 through the first connection line B10, and the first power supply B70 supplies power to the temperature compensation thermistor Rt2. The second power supply B80 also includes two batteries connected in series, and the second connection line B20 of the temperature compensation thermistor Rt2 is connected to the connection of the two batteries of the second power supply B80 of the second operational amplifier B60, and the second power supply B80 supplies power to the temperature compensation thermistor Rt2. The temperature compensation thermistor Rt2 is connected to the same-direction input terminal of the first operational amplifier B50 through the third connection line B30, and the temperature compensation thermistor Rt2 is connected to the same-direction input terminal of the second operational amplifier B60 through the fourth connection line B40. The temperature compensation thermistor Rt2 is connected to the self-balancing Wheatstone bridge through the four-wire method of the first connection line B10, the second connection line B20, the third connection line B30 and the fourth connection line B40.

[0039] The fifth connection line B90 of the bridge arm standard resistor Rcs is connected to the inverting input terminal of the first operational amplifier B50, and the sixth connection line B100 of the bridge arm standard resistor Rcs is connected to the inverting input terminal of the second operational amplifier B60. The output terminal of the first operational amplifier B50 is connected to the inverting input terminal of the first operational amplifier B50, and negative feedback is performed on the first operational amplifier B50. The output terminal of the second operational amplifier B60 is connected to the inverting input terminal of the second operational amplifier B60, and negative feedback is performed on the second operational amplifier B60.

[0040] The heating resistor Rh and the temperature acquisition resistor Rm are both connected to the sampler temperature control circuit 140, and the other end of the sampler temperature control circuit 140 is connected to the fourth analog-to-digital conversion circuit 110, and the fourth analog-to-digital conversion circuit 110 is connected to the processor at one end away from the sampler temperature control circuit 140. The temperature inside the sampler 20 is output to the processor and displayed through the fourth analog-to-digital conversion circuit 110. The heating resistor Rh is used to heat the inside of the sampler 20 so that the power measurement thermistor Rt1 and the temperature compensation thermistor Rt2 work at a steady-state temperature. The temperature acquisition resistor Rm is used to collect the internal temperature of the sampler 20 and control the heating power of the heating resistor Rh, ensuring that the power measurement thermistor Rt1 and the temperature compensation thermistor Rt2 work at a steady-state temperature.

[0041] More preferably, the heating resistor Rh includes various devices such as resistance wire and heating film, and no specific limitation is made here, as long as heating can be ensured so that the power measurement thermistor Rt1 and the temperature compensation thermistor Rt2 work at a steady-state temperature.

[0042] The power level preset circuit 10 includes a power setting circuit 60, a steady-state zeroing circuit 50, an analog adder 70 and a Wheatstone bridge. The power setting circuit 60 and the steady-state zeroing circuit 50 are both connected to the in-phase input terminal of the analog adder 70, and the reverse input terminal of the analog adder 70 is grounded; the output terminal of the analog adder 70 is connected to the Wheatstone bridge composed of the power measurement thermistor Rt1 and three standard resistors Rs. The power setting circuit 60, the steady-state zeroing circuit 50 and the analog adder 70 are used to set the DC replacement power voltage.

[0043] The Wheatstone bridge includes three standard resistors Rs and a sampler power measurement thermistor Rt1, and the three standard resistors Rs and the sampler power measurement thermistor Rt1 serve as four arms of the Wheatstone bridge respectively. The Wheatstone bridge is used to measure the difference between the voltage across the power measurement thermistor Rt1 and the voltage across the standard resistor Rs, thereby obtaining the resistance value of the power measurement thermistor Rt1, and obtaining the voltage value Vs of the standard resistor Rs through the first analog-to-digital conversion circuit 80 of the digital processing circuit 30. The voltage value Vm of the sampler power measurement thermistor Rt1 is obtained through the second analog-to-digital conversion circuit 90 of the digital processing circuit 30.

[0044] When the sampler 20 is heated to a steady-state temperature and the RF microwave power level control device with temperature compensation is not in a power level control state, the voltage difference between the power measurement thermistor Rt1 and the standard resistor Rs is 0V by adjusting the steady-state zeroing circuit 50, and the voltage V of the standard resistor at this time is measured. s，bal When the RF microwave power level control device with temperature compensation is in the power level control state, the DC substitution power voltage is adjusted by the power setting circuit 60 so that the voltage across the standard resistor Rs is the DC substitution voltage of the preset power level.

[0045] Due to the difference between the power measurement thermistor Rt1 and the laboratory temperature, the zero point voltage of the sampler 20 is different in steady state. The steady state zero adjustment circuit 50 adjusts the interpolation of the voltage on the power measurement thermistor Rt1 and the voltage on the standard resistor Rs to within a specific range.

[0046] More preferably, the voltage difference between the voltage on the power measurement thermistor Rt1 and the voltage on the standard resistor Rs is 0V; at this time, the output voltage of the power setting circuit 60 is the voltage when the power is 0mW, that is, the maximum voltage. It should be noted that the power setting circuit 60 has an opposite direction of change to the output voltage, that is, the output voltage decreases as the power setting increases.

[0047] The steady-state zeroing circuit 50 is composed of one or more capacitors, resistors and operational amplifiers. When the power level preset circuit 10 has no input value, the steady-state zeroing circuit 50 makes the output value of the power level preset circuit 10 zero, which can eliminate the offset voltage and noise in the power level preset circuit 10, thereby improving the accuracy and stability of the power level preset circuit 10.

[0048] The digital processing circuit 30 includes a sampler temperature compensation conversion circuit 130, a sampler temperature control circuit 140, a first analog-to-digital conversion circuit 80, a second analog-to-digital conversion circuit 90, a third analog-to-digital conversion circuit 100, a fourth analog-to-digital conversion circuit 110 and a processor 120. The first analog-to-digital conversion circuit 80 is connected to the standard resistor Rs and is used to collect the voltage value Vs of the standard resistor Rs. The second analog-to-digital conversion circuit 90 is connected to the power measurement thermistor Rt1 and is used to collect the voltage value Vm of the power measurement thermistor Rt1.

[0049] The temperature compensation thermistor Rt2 is connected to the sampler temperature compensation conversion circuit 130, and the resistance signal of the temperature compensation thermistor Rt2 is converted into a voltage value Vc through the sampler temperature compensation conversion circuit 130. The other end of the sampler temperature compensation conversion circuit 130 is connected to the third analog-to-digital conversion circuit 100, and the third analog-to-digital conversion circuit 100 is used to collect the voltage value Vc of the temperature compensation thermistor Rt2.

[0050] The sampler temperature control circuit is connected to the heating resistor Rh, and is used to control the heating power of the heating resistor Rh. At the same time, the resistance signal of the temperature acquisition resistor Rm is converted into a voltage signal Vt through a three-wire resistance measurement circuit; the other end of the sampler temperature control circuit is connected to the fourth analog-to-digital conversion circuit 110, and the fourth analog-to-digital conversion circuit 110 is used to collect the voltage value Vt of the temperature acquisition resistor Rm, and convert the voltage value Vt into a temperature value through the processor 120 and display it.

[0051] The processor 120 is respectively connected to the output ends of the first analog-to-digital conversion circuit 80, the second analog-to-digital conversion circuit 90, the third analog-to-digital conversion circuit 100, and the fourth analog-to-digital conversion circuit 110, and digitally processes the signals respectively collected by the first analog-to-digital conversion circuit 80, the second analog-to-digital conversion circuit 90, the third analog-to-digital conversion circuit 100, and the fourth analog-to-digital conversion circuit 110 to obtain a power value after temperature compensation.

[0052] More preferably, the processor 120 can be connected to an external display screen to display the temperature value, or can be connected to a pointer type or digital meter to display the temperature value. The specific display method is not limited, as long as it can ensure that the corresponding temperature value can be fed back and displayed in time.

[0053] The in-phase input terminal of the analog subtractor 160 is connected to the standard resistor Rs of the power level preset circuit 10, and the voltage Vs of the standard resistor Rs is input to the analog subtractor 160. The analog subtractor 160 inputs the voltage Vs of the standard resistor and the voltage Vp output by the digital-to-analog conversion circuit 150 into the analog subtractor 160 for subtraction and amplification. The output terminal of the analog subtractor 160 is connected to the PID control circuit 170, and the PID control circuit 170 feedback-adjusts the power of the radio frequency microwave.

[0054] The workflow is as follows:

[0055] The voltage V of the standard resistor Rs when not in the power level control state is passed through the RF microwave power level control device with temperature compensation. s，bal The voltage Vm of the power measuring thermistor Rt1 under the power level control state is used to calculate the RF microwave power Pm without temperature compensation, as shown in formula (1). The Pm calculation formula is as follows:

[0056]

[0057] By calculating the voltage Vc of the temperature compensation thermistor Rt2, the compensation power Pc is calculated, as shown in formula (2). Pc is calculated as follows:

[0058]

[0059] Where: V c，NoRF V is the voltage of the temperature compensation thermistor Rt2 when no RF power is loaded; c，RF is the voltage of the temperature compensation thermistor Rt2 when RF power is loaded; R cs is the standard resistance Rcs on the bridge arm opposite to Rt2 in the temperature compensation conversion circuit. Thus, the actual RF DC replacement power P is calculated. RF，sub , as shown in formula (3):

[0060]

[0061] Where: P RF，sub is the current actual RF DC replacement power; CF is the calibration factor of the sampler at the current frequency.

[0062] The power level control circuit 40 includes a digital-to-analog conversion circuit 150, an analog subtractor 160, and a PID control circuit 170. The digital-to-analog conversion circuit 150 is connected to the processor 120, and the other end is connected to the inverting input end of the analog subtractor 160. The digital-to-analog conversion circuit 150 converts the voltage corresponding to the temperature-compensated power value calculated by the processor 120 into an analog voltage value Vp and inputs it into the analog subtractor 160. As shown in formula (4), the output voltage Vp of the digital-to-analog conversion circuit 150 is calculated:

[0063]

[0064] Where: V s，bal is the voltage of the standard resistor Rs when the RF microwave power level control device with temperature compensation is not in the power level control state in a steady state; P RF，sub is the actual current RF DC replacement power.

[0065] It should be noted that the above-mentioned calculation method for temperature compensation using the radio frequency microwave power level control device with temperature compensation described in the utility model is a prior art, and the utility model is only an improvement on the existing temperature compensation device.

[0066] The radio frequency microwave power level control device with temperature compensation realizes the temperature compensation function of the radio frequency microwave power level control device by adopting a sampler with temperature compensation and adding relevant functional circuits such as conversion, acquisition, and digital processing. By adding the temperature compensation function, the error introduced by the sampler due to temperature drift is reduced, and the accuracy of radio frequency microwave power level control is improved.

[0067] The above content is an explanation of the preferred embodiments of the present invention, which can help those skilled in the art to more fully understand the technical solution of the present invention. However, these embodiments are merely illustrative, and it cannot be determined that the specific implementation methods of the present invention are limited to the description of these embodiments. For ordinary technicians in the technical field to which the present invention belongs, without departing from the concept of the present invention, several simple deductions and transformations can be made, which should be regarded as belonging to the protection scope of the present invention.

Claims

1. A radio frequency microwave power level control device with temperature compensation, characterized in that: It includes a sampler, a power level preset circuit, a digital processing circuit and a power level control circuit; The sampler comprises a power measurement thermistor, a temperature compensation thermistor, a heating resistor and a temperature acquisition resistor which are independently connected in parallel; the power measurement thermistor, the temperature compensation thermistor, the heating resistor and the temperature acquisition resistor are respectively connected to the digital processing circuit; the other end of the digital processing circuit is connected to the power level control circuit; The three standard resistors of the power level preset circuit and the power measurement thermistor form a Wheatstone bridge, which is then connected to the digital processing circuit; the other end is connected to the power level control circuit; the entire device is electrically connected to form a complete closed loop.

2. The RF microwave power level control device with temperature compensation according to claim 1, characterized in that: The digital processing circuit includes a sampler temperature compensation conversion circuit, a sampler temperature control circuit, a first analog-to-digital conversion circuit, a second analog-to-digital conversion circuit, a third analog-to-digital conversion circuit, a fourth analog-to-digital conversion circuit and a processor; The first analog-to-digital conversion circuit is connected to the standard resistor; the second analog-to-digital conversion circuit is connected to the power measurement thermistor; the third analog-to-digital conversion circuit is connected to the sampler temperature compensation conversion circuit, and then connected to the temperature compensation thermistor; the fourth analog-to-digital conversion circuit is connected to the sampler temperature control circuit, and then connected to the heating resistor and the temperature acquisition resistor.

3. The RF microwave power level control device with temperature compensation according to claim 2, characterized in that: The first analog-to-digital conversion circuit, the second analog-to-digital conversion circuit, the third analog-to-digital conversion circuit, and the fourth analog-to-digital conversion circuit are respectively connected in parallel, and the output ends are connected to the processor, and the temperature-compensated power is displayed by the processor.

4. The RF microwave power level control device with temperature compensation according to claim 3, characterized in that: The sampler temperature compensation conversion circuit is a self-balanced Wheatstone bridge, and the temperature compensation thermistor is connected to the self-balanced Wheatstone bridge in a four-wire method, connected to the third analog-to-digital conversion circuit, and the DC component of the sampler temperature compensation conversion circuit is selected through the third analog-to-digital conversion circuit.

5. The RF microwave power level control device with temperature compensation according to claim 4, characterized in that: The temperature compensation thermistor, the bridge arm standard resistor, the first operational amplifier and the second operational amplifier form a self-balancing Wheatstone bridge; The positive power supply terminal and the negative power supply terminal of the first operational amplifier are respectively connected to the positive and negative poles of the first power supply; the positive power supply terminal and the negative power supply terminal of the second operational amplifier are respectively connected to the positive and negative poles of the second power supply; the first power supply includes two batteries connected in series, and the second power supply includes two batteries connected in series.

6. The RF microwave power level control device with temperature compensation according to claim 5, characterized in that: The temperature compensation thermistor is connected to the connection of two batteries of the first power supply of the first operational amplifier through a first connection line; the second connection line of the temperature compensation thermistor is connected to the connection of two batteries of the second power supply of the second operational amplifier; the temperature compensation thermistor is connected to the non-inverting input terminal of the first operational amplifier through a third connection line, and the temperature compensation thermistor is connected to the non-inverting input terminal of the second operational amplifier through a fourth connection line; The fifth connecting line of the bridge arm standard resistor is connected to the inverting input terminal of the first operational amplifier, and the sixth connecting line of the bridge arm standard resistor is connected to the inverting input terminal of the second operational amplifier; the output terminal of the first operational amplifier is connected to the inverting input terminal of the first operational amplifier; and the output terminal of the second operational amplifier is connected to the inverting input terminal of the second operational amplifier.

7. The RF microwave power level control device with temperature compensation according to claim 1, characterized in that: The power level preset circuit includes a power setting circuit, a steady-state zero adjustment circuit, an analog adder and a Wheatstone bridge; The power setting circuit and the steady-state zeroing circuit are both connected to the in-phase input terminal of the analog adder, and the inverting input terminal of the analog adder is grounded; the output terminal of the analog adder is connected to a Wheatstone bridge composed of the power measurement thermistor and three standard resistors.

8. The radio frequency microwave power level control device with temperature compensation according to claim 7, characterized in that: The Wheatstone bridge comprises three standard resistors and a sampler power measurement thermistor, which are respectively connected in series and in parallel as four arms of the Wheatstone bridge; one end of the power measurement thermistor away from the second analog-to-digital conversion circuit is grounded.

9. The radio frequency microwave power level control device with temperature compensation according to claim 2 or 8, characterized in that: The first analog-to-digital conversion circuit is connected to one of the standard resistors, and one end of the standard resistor away from the first analog-to-digital conversion circuit is grounded.

10. The radio frequency microwave power level control device with temperature compensation according to claim 1, characterized in that: The power level control circuit includes a digital-to-analog conversion circuit, an analog subtractor and a PID control circuit; The digital-to-analog conversion circuit is connected to the processor, and the other end is connected to the inverting input end of the analog subtractor. The output end of the analog subtractor is connected to the PID control circuit, and the PID control circuit feedback regulates the power of the radio frequency microwave.

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