Temperature compensation pre-detection high-precision amplitude stabilization method and network analyzer

Abstract

The invention relates to the technical field of network analyzers, and aims to solve the technical problem of low radio frequency power output precision. In order to solve the technical problem, the invention provides a temperature compensation pre-detection high-precision amplitude stabilization method and a network analyzer. The method comprises the following steps: detecting the temperature of the output end of a radio frequency main circuit; after the collected temperature value is calculated, the detection circuit outputs a compensation voltage value, meanwhile, reference voltage is output to the detection circuit, and after the compensation voltage value, the reference voltage and the voltage value of the detection circuit are summed, a correction voltage value is output; and the variable voltage carries out amplitude stabilization on the correction voltage value according to the acquired temperature value. The system also comprises a radio frequency main circuit, a detection circuit, an amplitude stabilizing circuit, a temperature detection circuit and a control assembly. The temperature detection circuit is provided with a temperature sensor; and an acquired temperature adjusting module of the control assembly is electrically connected with the temperature sensor and the variable capacitor respectively. The radio frequency power output precision is greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of network analyzers, and in particular to a temperature compensation pre-detection high-precision amplitude stabilization method and a network analyzer. Background Art

[0002] The network analyzer is a powerful comprehensive microwave measuring instrument, which is mainly used for scanning measurement in a wide frequency band to determine network parameters. It can directly measure the complex scattering parameters of active or passive, reversible or irreversible two-port and single-port networks, and give the amplitude, phase and frequency characteristics of each scattering parameter in a frequency sweep mode.

[0003] The network analyzer can automatically perform error correction on the measurement results point by point and convert dozens of other network parameters, such as input reflection coefficient, output reflection coefficient, voltage standing wave ratio, impedance (or admittance), attenuation (or gain), phase shift and group delay, as well as transmission parameters such as isolation and directivity.

[0004] Network analyzers are used to measure amplifiers, coaxial cables, power dividers, combiners, antennas, couplers, filters, isolators, branch distributors, crystals, SAWs, etc. Network analyzers can measure the following parameters: insertion loss, attenuation, isolation, gain, frequency response, in-band flatness, phase, group delay, return loss, SWR, characteristic impedance, 3dB bandwidth, out-of-band suppression, stopband bandwidth, rectangular coefficient, etc.

[0005] Network analyzers are very useful in measuring the linear characteristics of wireless radio frequency (RF) components and equipment, and can provide extremely high accuracy and repeatable measurement of wireless radio frequency (RF) components. When measuring, the network analyzer in the prior art has a different RF power output accuracy at different frequencies. It is very necessary to be able to perform more accurate RF component measurements and provide higher measurement accuracy requirements. For a table showing the relationship between the RF power output accuracy of the network analyzer and the frequency band of the network analyzer, see the attached Figure 1 , by the attached Figure 1 It can be seen that as the frequency band of the network analyzer increases, the accuracy of the network analyzer's RF power output decreases. Especially at frequencies between 26.5GHz and 43.5GHz and 50GHz, the accuracy is ±3.0dB and ±3.5db, which is too low and affects the measurement effect. Therefore, it is necessary to improve the existing network analyzer to improve the accuracy of the network analyzer's RF power output in the high frequency band (26.5GHz to 50GHz). Summary of the invention

[0006] Therefore, the technical problem to be solved by the present invention is to overcome the above-mentioned problems existing in the prior art.

[0007] In order to solve the above technical problems, on the one hand, the present invention provides a temperature compensation pre-detection high-precision amplitude stabilization method, including: detecting the temperature of the output end of the RF main circuit; calculating the collected temperature value and then outputting a compensation voltage value to the detection circuit, and at the same time outputting a reference voltage to the detection circuit, summing the compensation voltage value, the reference voltage and the detection circuit voltage value of the detection circuit and then outputting a correction voltage value; a variable voltage stabilizes the correction voltage value according to the collected temperature value.

[0008] In another aspect, the present invention provides a network analyzer, comprising:

[0009] A radio frequency main circuit, comprising a radio frequency signal input terminal, an adjustable attenuator and a radio frequency signal output terminal connected in sequence;

[0010] A detection circuit, one end of which is connected between the adjustable attenuator and the RF signal output terminal through a signal distribution component, and the other end of which is connected to the adjustable attenuator; the detection circuit includes a detection diode, a logarithmic amplifier and a comparison integration amplifier connected in sequence;

[0011] An amplitude stabilization circuit includes a variable capacitor, wherein the variable capacitor is connected in parallel to the comparison integral amplifier;

[0012] The temperature detection circuit has one end connected between the logarithmic amplifier and the comparison integral amplifier through a combiner, and the other end is provided with a temperature sensor; the temperature sensor is arranged close to the radio frequency main circuit;

[0013] The control component includes a temperature acquisition adjustment module, a compensation algorithm module and a calibration module; the temperature acquisition adjustment module is electrically connected to the temperature sensor and the variable capacitor respectively; the compensation algorithm module and the calibration module are electrically connected to the output end of the logarithmic amplifier respectively.

[0014] In one embodiment of the present invention, the temperature value detected by the temperature sensor is transmitted to the acquisition temperature adjustment module of the control component, and the compensation algorithm module of the control component compares and calculates the temperature value and outputs a compensation voltage value.

[0015] In one embodiment of the present invention, the compensation algorithm module performs comparison calculation based on a parameter table, and the parameter table is a relationship table between temperature values ​​and compensation voltage values.

[0016] In one embodiment of the present invention, the control component further includes a control module, and the control module is electrically connected to the acquisition temperature adjustment module, the compensation algorithm module and the calibration module.

[0017] In one embodiment of the present invention, the variable capacitor includes a plurality of correction branches connected in parallel; the correction branch includes a switch and a capacitor connected in series, and the switch is electrically connected to the control component; and the capacitance values ​​of the plurality of correction branches are different.

[0018] In one embodiment of the present invention, the radio frequency main circuit further includes a fixed amplifier connected between the adjustable attenuator and the radio frequency signal output terminal.

[0019] In one embodiment of the present invention, the detection circuit further includes an exponential amplifier connected between the adjustable attenuator and the comparison and integration amplifier.

[0020] In one embodiment of the present invention, the signal distribution component is a directional coupler.

[0021] In one embodiment of the present invention, the compensation algorithm module and the calibration module are incorporated into the detection circuit through a combiner.

[0022] In one embodiment of the present invention, the temperature sensor is arranged close to the radio frequency signal output terminal of the radio frequency main circuit.

[0023] The above technical solution of the present invention has the following advantages compared with the prior art:

[0024] The temperature compensation pre-detection high-precision amplitude stabilization method and network analyzer described in the present invention collect the temperature of the RF main circuit in real time through a temperature sensor, and then calculate the compensation voltage value output by the post-detection circuit according to the collected temperature value, so as to compensate the compensation voltage value to the detection circuit voltage value of the detection circuit. It can be seen that this embodiment can pre-detect the real-time temperature of the network analyzer and make compensation in advance, so that the RF power output accuracy of the network analyzer is greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below according to specific embodiments of the present invention in conjunction with the accompanying drawings, wherein:

[0026] Figure 1 It is a table showing the relationship between the RF power output accuracy of the network analyzer and the frequency band of the network analyzer;

[0027] Figure 2 is a circuit schematic diagram of a network analyzer in a preferred embodiment of the present invention;

[0028] Figure 3 yes Figure 1 A schematic diagram of the structure of the control components in the network analyzer;

[0029] Figure 4 yes Figure 1 Circuit diagram of variable capacitor in network analyzer;

[0030] Figure 5 It is the parameter table based on which the compensation algorithm module calculates;

[0031] Explanation of the reference numerals in the specification: 1. RF signal input terminal; 2. Adjustable attenuator; 3. RF signal output terminal; 4. Detection diode; 5. Logarithmic amplifier; 6. Comparison integrating amplifier; 7. Variable capacitor; 7.1. Switch; 7.2. Capacitor; 8. Temperature sensor; 9. Acquisition temperature adjustment module; 10. Compensation algorithm module; 11. Calibration module; 12. Control module; 13. Fixed amplifier; 14. Directional coupler; 15. Exponential amplifier; 16. Combiner. DETAILED DESCRIPTION

[0032] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0033] During use, the inventor found that temperature changes have a certain impact on the RF power output accuracy of the network analyzer. After testing, when the temperature rises by 1 degree, the RF power will decrease by about 0.05dB. Therefore, this application improves the RF power output accuracy of the network analyzer through temperature compensation. The specific compensation structure and compensation method are as follows.

[0034] Reference Figure 1 to Figure 5 As shown, the present invention provides a network analyzer, which can improve the accuracy through a temperature compensation pre-detection high-precision amplitude stabilization method. The network analyzer includes:

[0035] The RF main circuit includes an RF signal input terminal 1, an adjustable attenuator 2 and an RF signal output terminal 3 which are connected in sequence; the RF signal input terminal 1 is used for inputting RF signals. The adjustable attenuator 2 is used for adjusting the output signal of the RF signal output terminal 3. The RF signal output terminal 3 is used for outputting signals.

[0036] The detection circuit has one end connected between the adjustable attenuator 2 and the RF signal output terminal 3 through a signal distribution component, and the other end connected to the adjustable attenuator 2; the detection circuit includes a detection diode 4, a logarithmic amplifier 5 and a comparison integral amplifier 6 connected in sequence. The detection diode 4 is used to convert the power value into a voltage value, which is then convenient for subsequent correction by a temperature compensation method. The logarithmic amplifier 5 plays a role in amplifying the detection signal. The comparison integral amplifier 6 plays a role in signal amplification.

[0037] The amplitude stabilization circuit includes a variable capacitor 7, which is connected in parallel to the comparison and integration amplifier 6. The amplitude is precisely stabilized by switching different capacitor 7.2 gear values.

[0038] The temperature detection circuit has one end connected between the logarithmic amplifier 5 and the comparison integrating amplifier 6 through a combiner 16, and the other end is provided with a temperature sensor 8; the temperature sensor 8 is arranged close to the RF main circuit;

[0039] The control component includes a temperature acquisition adjustment module 9, a compensation algorithm module 10 and a calibration module 11; the temperature acquisition adjustment module 9 is electrically connected to the temperature sensor 8 and the variable capacitor 7 respectively; the compensation algorithm module 10 and the calibration module 11 are electrically connected to the output end of the logarithmic amplifier 5 respectively.

[0040] The embodiment of the present invention provides a temperature compensation pre-detection high-precision amplitude stabilization method, including: detecting the temperature at the output end of the RF main circuit; calculating the collected temperature value and then outputting the compensation voltage value of the detection circuit. For example, the temperature value detected by the temperature sensor 8 is transmitted to the acquisition temperature adjustment module 9 of the control component, and the compensation algorithm module 10 of the control component compares and calculates the temperature value and outputs the compensation voltage value. Furthermore, the compensation algorithm module 10 compares and calculates based on a parameter table, and the parameter table is a relationship table between the temperature value and the compensation voltage value. The relationship is obtained by multiple tests and debugging. The relationship table is shown in the attached Figure 5 At the same time, the calibration module 11 outputs a reference voltage to the detection circuit. Then the compensation voltage value, the reference voltage and the detection circuit voltage value of the detection circuit are summed and then output to the comparison integral amplifier 6 to output the correction voltage value. The variable voltage stabilizes the correction voltage value according to the collected temperature value.

[0041] Specifically, the present application collects the temperature of the RF main circuit in real time through the temperature sensor 8, and then calculates the compensation voltage value output by the detector circuit according to the collected temperature value, so as to compensate the compensation voltage value to the detector circuit voltage value of the detector circuit. It can be seen that the present embodiment can pre-detect the real-time temperature of the network analyzer, make compensation in advance, and greatly improve the RF power output accuracy of the network analyzer.

[0042] After testing, the RF power output accuracy of the high frequency band (26.5GHz~50GHz) can be improved by about 0.5dB (26.5GHz~43.5GHz can be improved to ±2.5dB, 43.5GHz~50GHz can be improved to ±3.0dB). Figure 1 It can be seen that the present application can greatly improve the RF power output accuracy of the network analyzer, making the network analyzer test more accurate.

[0043] Furthermore, the control component further includes a control module 12, which is electrically connected to the acquisition temperature adjustment module 9, the compensation algorithm module 10 and the calibration module 11. Specifically, this embodiment can realize fully automatic adjustment without manual operation and has high efficiency.

[0044] Further, the variable capacitor 7 includes a plurality of correction branches in parallel; the correction branch includes a switch 7.1 and a capacitor 7.2 in series, and the switch 7.1 is electrically connected to the control component; the values ​​of the capacitors 7.2 of the plurality of correction branches are different. By controlling the on and off of the switches 7.1 of each correction branch through the control component, more combinations can be achieved, thereby affecting the integration time t of the operational amplifier, since t = R × C, R is the resistance value, and C is the value of the capacitor 7.2. Therefore, by changing the value of the RC time constant, changing the value of the capacitor 7.2C or changing the value of the resistor R, the time required for the output voltage to reach saturation can be changed. Thereby improving the measurement efficiency. For example, there are four correction branches. The capacitors 7.2 on the four correction branches are C1, C2, C3 and C4 respectively. The values ​​of C1, C2, C3 and C4 are different. It can achieve 16 different combinations; when the temperature change is less than or equal to 1 degree Celsius, it is 1 gear, and so on, this embodiment can achieve the switching of 16 gears. Since the temperature of the machine changes by about 15 degrees when it is turned on and the machine runs for a period of time, the 16-speed switching in this embodiment can be suitable for actual conditions.

[0045] Furthermore, the RF main circuit also includes a fixed amplifier 13 connected between the adjustable attenuator 2 and the RF signal output terminal 3. Specifically, the fixed amplifier 13 in this embodiment can amplify the signal output by the adjustable attenuator 2 and then transmit it to the RF signal output terminal 3, thereby improving the quality and efficiency of the signal.

[0046] Furthermore, the signal distribution component is a directional coupler 14. Specifically, the directional coupler 14 divides the signal output by the adjustable attenuator 2 into two parts, one part is output to the RF signal output terminal 3, and the other part is output to the detection circuit. It has stable performance and low cost.

[0047] Furthermore, the detection circuit further includes an exponential amplifier 15, which is connected between the adjustable attenuator 2 and the comparison and integration amplifier 6. Specifically, the exponential amplifier 15 can amplify the feedback signal, making it easier for the adjustable attenuator 2 to identify it.

[0048] Furthermore, the temperature sensor 8 is arranged close to the RF signal output terminal 3 of the RF main circuit. Specifically, the data collected in this way is more accurate.

[0049] Furthermore, the compensation algorithm module 10 and the calibration module 11 are incorporated into the detection circuit through the combiner 16 .

[0050] Obviously, the above embodiments are merely examples for the purpose of clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the present invention.

Claims

1. A temperature compensation pre-detection high-precision amplitude stabilization method, characterized by: include: Detect the temperature at the output end of the RF main circuit; After calculating the collected temperature value, the detector circuit outputs a compensation voltage value, and at the same time outputs a reference voltage to the detector circuit, and then outputs a correction voltage value after summing the compensation voltage value, the reference voltage and the detector circuit voltage value of the detector circuit; The variable voltage stabilizes the correction voltage value according to the collected temperature value.

2. A network analyzer, characterized in that: Measuring parameters using the temperature compensation pre-detection high-precision amplitude stabilization method described in claim 1; The network analyzer comprises: A radio frequency main circuit, comprising a radio frequency signal input terminal, an adjustable attenuator and a radio frequency signal output terminal connected in sequence; A detection circuit, one end of which is connected between the adjustable attenuator and the RF signal output terminal through a signal distribution component, and the other end is connected to the adjustable attenuator; the detection circuit comprises a detection diode, a logarithmic amplifier and a comparison integration amplifier connected in sequence; An amplitude stabilization circuit, comprising a variable capacitor, wherein the variable capacitor is connected in parallel to the comparison and integration amplifier; A temperature detection circuit, one end of which is connected between the logarithmic amplifier and the comparison integrating amplifier through a combiner, and the other end of which is provided with a temperature sensor; the temperature sensor is arranged close to the RF main circuit; The control component includes a temperature acquisition adjustment module, a compensation algorithm module and a calibration module; the temperature acquisition adjustment module is electrically connected to the temperature sensor and the variable capacitor respectively; the compensation algorithm module and the calibration module are electrically connected to the output end of the logarithmic amplifier respectively.

3. The network analyzer according to claim 2, characterized in that: The temperature value detected by the temperature sensor is transmitted to the acquisition temperature adjustment module of the control component, and the compensation algorithm module of the control component compares and calculates the temperature value and outputs a compensation voltage value to compensate the voltage value of the detection circuit.

4. The network analyzer according to claim 3, characterized in that: The compensation algorithm module performs comparative calculations based on a parameter table, which is a relationship table between temperature values ​​and compensation voltage values.

5. The network analyzer according to claim 2, characterized in that: The control component also includes the control module, which is electrically connected to the acquisition temperature adjustment module, the compensation algorithm module and the calibration module.

6. The network analyzer according to claim 5, characterized in that: The variable capacitor includes a plurality of correction branches connected in parallel; the correction branch includes a switch and a capacitor connected in series, and the switch is electrically connected to the control component; the capacitance values ​​of the plurality of correction branches are different.

7. The network analyzer according to claim 2, characterized in that: The radio frequency main circuit also includes a fixed amplifier connected between the adjustable attenuator and the radio frequency signal output terminal.

8. The network analyzer according to claim 2, characterized in that: The detection circuit further includes an exponential amplifier connected between the adjustable attenuator and the comparison integration amplifier.

9. The network analyzer according to claim 2, characterized in that: The signal distribution component is a directional coupler.

10. The network analyzer according to claim 2, characterized in that: The temperature sensor is arranged close to the radio frequency signal output end of the radio frequency main circuit.

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