Temperature-compensation voltage-controlled oscillation circuit for self-inspection of microwave channel

Abstract

The utility model discloses a temperature-compensation voltage-controlled oscillation circuit for microwave channel self-inspection, and the circuit comprises a self-inspection power supply circuit which is used for outputting stable DC power supply voltage; the temperature compensation circuit is used for outputting tuning voltage Vt; a voltage-controlled oscillator, the voltage tuning end of which is connected with the tuning voltage Vt of the partial voltage output end of the temperature compensation circuit, and which is used for outputting a microwave continuous wave signal; the microwave modulation circuit is used for receiving the microwave continuous wave signal output by the voltage-controlled oscillator and generating a microwave pulse signal; the microwave switch receives the microwave pulse signal generated by the microwave modulation circuit through a power divider and is used for selecting a microwave pulse self-checking signal; and the feed-in coupling circuit is used for feeding the microwave pulse self-checking signal into the microwave channel. According to the utility model, the voltage-controlled oscillator is enabled to maintain stable frequency output at different temperatures, and the consistency and repeatability of microwave channel detection are improved.

Description

Technical Field

[0001] The utility model belongs to the field of microwave transceiver equipment, and particularly relates to a temperature-compensated voltage-controlled oscillator circuit for microwave channel self-testing. Background Art

[0002] With the rapid development of fields such as microwave communication, radar countermeasure, and radar detection, the microwave transceiver channel, as the core component of the microwave system, directly affects the overall function of the microwave system whether its function is normal or not. Therefore, the testability of the microwave channel in complex electronic equipment has become an essential function of microwave equipment. Especially for phased array radars with hundreds or even thousands of microwave channels, the microwave channel self-test function is even more important. The temperature-compensated voltage-controlled oscillator circuit for microwave channel self-testing is a microwave self-test circuit used to detect whether the function of the microwave transceiver channel is normal, and is widely used in various microwave transceiver equipment.

[0003] Currently, the common microwave channel self-test uses a voltage-controlled oscillator within the required frequency band to generate a self-test source signal. The self-test source signal is then fed into the microwave channel through coupling and / or switching. The front and / or rear-end circuits of the microwave channel obtain the strength of the microwave self-test signal through a microwave detector or an intermediate-frequency ADC sampling circuit after mixing, and then determine whether the state of the detected microwave channel is normal. Among them, the voltage-controlled oscillator circuit is an open-loop system, and the output frequency of the voltage-controlled oscillator is greatly affected by temperature changes. Especially in aerospace microwave equipment with a large operating temperature range, it leads to poor repeatability and consistency of the detected voltage at the rear end.

[0004] Therefore, further research and innovation are needed to solve the above problems existing in the prior art. Summary of the Utility Model

[0005] The purpose of the utility model is to provide a temperature-compensated voltage-controlled oscillator circuit for microwave channel self-testing to solve the above problems existing in the prior art.

[0006] Technical Solution: The temperature-compensated voltage-controlled oscillator circuit for microwave channel self-testing includes:

[0007] A self-test power supply circuit for outputting a stable DC power supply voltage, including an output voltage VCC and an output voltage VEE;

[0008] A temperature compensation circuit connected to the output voltage VCC of the self-test power supply circuit for outputting a tuning voltage Vt;

[0009] A voltage-controlled oscillator, the power supply terminal of the voltage-controlled oscillator is connected to the output voltage VCC of the self-test power supply circuit, and the voltage tuning terminal of the voltage-controlled oscillator is connected to the tuning voltage Vt at the voltage division output terminal of the temperature compensation circuit, for outputting a microwave continuous wave signal with the required frequency;

[0010] A microwave modulation circuit that receives the microwave continuous wave signal output by a voltage controlled oscillator and generates a microwave pulse signal;

[0011] A microwave switch, connected to the output voltage VEE of the self - test power supply circuit, receives the microwave pulse signal generated by the microwave modulation circuit through a power divider, and is used to select a microwave pulse self - test signal;

[0012] A feeding and coupling circuit that receives the microwave pulse self - test signal selected by the microwave switch and is used to feed the microwave pulse self - test signal into the microwave channel.

[0013] According to one aspect of the present application, the self - test power supply circuit includes a linear voltage regulator or a switching voltage regulator and has an enable control signal.

[0014] According to one aspect of the present application, the temperature compensation circuit uses a thermistor and ordinary resistors in parallel and series to form a voltage - dividing network, and obtains the tuning voltage Vt through the voltage - dividing network.

[0015] According to one aspect of the present application, the voltage - dividing network includes a thermistor R T , a first ordinary resistor R P , a second ordinary resistor R S , a third ordinary resistor R dn , where one end of the thermistor R T and the first ordinary resistor R P are simultaneously connected to the output voltage VCC of the self - test power supply circuit, the other ends of the thermistor R T and the first ordinary resistor R P are simultaneously connected to one end of the second ordinary resistor R S , the other end of the second ordinary resistor R S is connected to one end of the third ordinary resistor R dn , and the other end of the third ordinary resistor R dn is grounded.

[0016] According to one aspect of the present application, the microwave modulation circuit includes a fixed attenuator, a microwave filter, and a microwave modulator. The microwave continuous wave signal output by the voltage controlled oscillator is connected to the microwave filter after passing through the fixed attenuator, and a microwave signal is output; the microwave signal is connected to the microwave modulator, and the microwave modulator is connected to the output voltage VCC of the self - test power supply circuit. The microwave modulator generates a microwave pulse signal with a predetermined pulse width and period under the action of the microwave signal and a preset modulation signal.

[0017] According to one aspect of the present application, the microwave modulator is composed of a predetermined number of GaAs FET process switches connected in series, and the modulation depth of the microwave modulator > 110dB.

[0018] According to one aspect of the present application, the microwave switch is composed of a predetermined number of single-pole single-throw switches. The opening and closing times of the microwave switch for microwave pulse signals are < 30 ns, and the isolation degree of the microwave switch for microwave pulse signals is > 40 dB.

[0019] According to one aspect of the present application, the feeding and coupling circuit includes a predetermined number of directional couplers.

[0020] According to one aspect of the present application, the microwave modulation circuit further includes a microwave amplifier.

[0021] According to one aspect of the present application, the thermistor is a negative temperature coefficient thermistor or a positive temperature coefficient thermistor.

[0022] Beneficial effects: The temperature compensation circuit in the present application obtains the tuning voltage of the voltage-controlled oscillator in the form of thermistor voltage division, so that the voltage-controlled oscillator maintains stable frequency output at different temperatures, overcomes the problem that the output frequency of the traditional voltage-controlled oscillator circuit varies greatly at high and low temperatures, and improves the consistency and repeatability of microwave channel detection; at the same time, in view of the non-linear logarithmic relationship between the resistance value of the thermistor and the temperature, a linearization process is realized by means of parallel and series connection with ordinary resistors, so that the circuit structure is simple, the power consumption is low, the cost is low, and the practicability is strong. Description of the Drawings

[0023] Figure 1 It is a schematic block diagram of the microwave channel self-checking circuit of the present utility model.

[0024] Figure 2 It is a linearization circuit diagram of the NTC thermistor of the present utility model.

[0025] Figure 3 It is a voltage division output circuit diagram after linearization of the NTC thermistor of the present utility model.

[0026] Figure 4 It is a corresponding relationship diagram between the resistance value of the NTC thermistor and the temperature of the present utility model.

[0027] Figure 5 It is a corresponding relationship diagram between the resistance value of the NTC thermistor after linearization processing and the temperature of the present utility model. Detailed Embodiment

[0028] As Figure 1As shown in the figure, the present application proposes a temperature-compensated voltage-controlled oscillator circuit for microwave channel self-check, which includes a voltage-controlled oscillator, a temperature compensation circuit, a self-check power supply circuit, a microwave modulation circuit, a microwave switch, and a feeding and coupling circuit. Among them, the self-check power supply circuit is used to output a stable DC power supply voltage, including an output voltage VCC and an output voltage VEE; the temperature compensation circuit is connected to the output voltage VCC of the self-check power supply circuit and is used to output a tuning voltage Vt; the voltage-controlled oscillator, the power supply terminal of the voltage-controlled oscillator is connected to the output voltage VCC of the self-check power supply circuit, and the voltage tuning terminal of the voltage-controlled oscillator is connected to the tuning voltage Vt of the voltage-dividing output terminal of the temperature compensation circuit, and is used to output a microwave continuous wave signal; the microwave modulation circuit receives the microwave continuous wave signal output by the voltage-controlled oscillator and generates a microwave pulse signal; the microwave modulation circuit includes a fixed attenuator, a microwave filter, and a microwave modulator. The microwave continuous wave signal output by the voltage-controlled oscillator is connected to the microwave filter after passing through the fixed attenuator. The microwave filter is mainly used to filter out the sub-harmonic and high-order harmonic signals of the self-check signal generated by the voltage-controlled oscillator; the microwave signal output by the microwave filter is connected to the microwave modulator. The microwave modulator is connected to the output voltage VCC of the self-check power supply circuit. The microwave modulator generates a microwave pulse signal with a predetermined pulse width and period under the action of the microwave signal and a preset modulation signal MOD.

[0029] The microwave pulse signal is then fed into the microwave channel to be tested through a power divider, a microwave switch, and a feeding and coupling circuit for channel self-check. Specifically: the microwave switch is connected to the output voltage VEE of the self-check power supply circuit and receives the microwave pulse signal generated by the microwave modulation circuit through the power divider, and is used to select the microwave pulse self-check signal; the feeding and coupling circuit includes a predetermined number of directional couplers and receives the microwave pulse self-check signal selected by the microwave switch, and is used to feed the microwave pulse self-check signal into the microwave channel.

[0030] In this embodiment, the voltage-controlled oscillator outputs a microwave signal with a stable frequency under the action of the self-check power supply circuit and the temperature compensation circuit; the self-check power supply circuit provides a stable DC voltage for the voltage-controlled oscillator, the microwave modulation circuit, and the microwave switch; the microwave modulation circuit realizes pulse modulation of the microwave continuous wave signal under the action of the modulation signal MOD, and then outputs a microwave pulse self-check signal with a specified pulse width and period; the microwave switch is composed of a single-pole single-throw switch and selects to perform self-check on the microwave channel to be tested under the action of the switch signal Kn. This embodiment overcomes the disadvantage of poor output frequency stability of the traditional microwave self-check circuit in high and low temperature environments and improves the consistency and repeatability of microwave channel detection.

[0031] According to one aspect of the present application, the voltage-controlled oscillator outputs a microwave signal under the combined action of the self-checking power supply circuit and the temperature compensation circuit. The output microwave frequency of the voltage-controlled oscillator changes with the tuning voltage Vt, and its representation parameter is the voltage tuning sensitivity (MHz / V). Generally, the voltage tuning sensitivity of the voltage-controlled oscillator is a non-linear curve in the entire operating frequency band, but can be linearly approximated within a small frequency range.

[0032] In an embodiment of the present application, the selected voltage-controlled oscillator model is HGC592-15, and the output fundamental frequency range is 17 - 19 GHz. The second harmonic of its 18 GHz frequency, which is 36 GHz, is used as the self-checking signal frequency. The voltage tuning sensitivity of the voltage-controlled oscillator HGC592-15 near the output frequency of 18 GHz is 400 MHz / V. The tuning voltage when the voltage-controlled oscillator outputs the same microwave frequency at high and low temperatures is Vt_ X℃ . For example, the measured tuning voltages of the typical voltage-controlled oscillator HGC592-15 at different temperatures (corresponding to -55 °C, +25 °C, +85 °C respectively) when outputting 18 GHz are: Vt_ -55℃ = 2.19 V, Vt_ +25℃ = 2.55 V, Vt_ +85℃ = 2.84 V. According to the tuning voltage values at different temperatures, the fitting curve of the tuning voltage and temperature at a specified frequency can be obtained (using a linear equation for engineering approximate fitting), and the corresponding mathematical relationship is Vt_ X℃ = F(X) = AX + B, where A and B are constants, and X is the operating temperature (°C). In this embodiment, Vt_ X℃ = 0.004643X + 1.1771295.

[0033] According to one aspect of the present application, the temperature compensation circuit uses a negative temperature coefficient (NTC) thermistor and ordinary resistors to form a voltage dividing network through parallel and series connections, and obtains the tuning voltage Vt of the voltage-controlled oscillator from the voltage dividing network. The voltage dividing network includes a thermistor R T , a first ordinary resistor R P , a second ordinary resistor R S , a third ordinary resistor R dn , where one end of the thermistor R T and the first ordinary resistor R P are simultaneously connected to the output voltage VCC of the self-checking power supply circuit. The other ends of the thermistor R T and the first ordinary resistor R P are simultaneously connected to one end of the second ordinary resistor R S . The other end of the second ordinary resistor R S is connected to one end of the third ordinary resistor R dn . The other end of the third ordinary resistor R dnThe other end is grounded.

[0034] The relationship between the resistance value of the NTC thermistor and temperature is generally described by the Arrhenius formula: R T =R0 exp[Ea / ( kT)]==R0 exp[B / T], where R0 represents the resistance value at the reference temperature, exp( ) represents the exponential function, Ea is the activation energy, indicating the energy characteristics of the thermistor material, k represents the Boltzmann constant, and B represents the material constant of the thermistor. In actual use, two basic electrical parameters are generally used to represent the electrical parameters of the NTC thermistor: (1) The resistance value at the reference temperature is R 25 , that is, the resistance value at 25°C; (2) The B value is defined as B = Ea / k, which represents the degree of change of the resistance value of the thermistor with temperature. The B value depends on the proportion content of Co, Mn, Cu, Ni metal oxides in the thermistor material. It can be seen from the thermistor calculation formula that the resistance value R T of the NTC thermistor changes exponentially with temperature T. In the temperature compensation circuit of this embodiment, linearization processing is first performed on the NTC resistor. As Figure 2 shown, the NTC thermistor is first connected in parallel with the ordinary resistor R P , and then connected in series with the ordinary resistor R S to achieve a linear change relationship between the resistance value R UP after linearization processing and temperature T, where R UP =R T / / R P +R S =( R T * R P ) / ( R T + R P )+ R S . As Figure 3 shown, the NTC thermistor linearization circuit and the ordinary resistor R dn are connected in series to form a voltage dividing circuit for the output voltage VCC. The output voltage of the voltage dividing circuit is connected to the voltage tuning terminal of the voltage controlled oscillator to adjust the output frequency of the voltage controlled oscillator. The output tuning voltage Vt = VCC*R dn / (R dn +R UP )=VCC*R dn / [R dn +( R T * R P ) / ( R T + R P )+ R S .

[0035] In one embodiment of the present application, the thermistor selected is of model J-CMFA103J3950HANT, and the corresponding R 25 = 10 kΩ, B = 3950; the ordinary resistors R P and the ordinary resistor R S are both 6.8 kΩ, the ordinary resistor R dn = 10 kΩ, and the corresponding relationship between the resistance value of the resistor and the temperature is as Figure 4 shown. From Figure 4 the display curve, it can be seen that the resistance value RT of the NTC thermistor changes exponentially with the temperature T, and the linearity is poor; the corresponding relationship between the resistance value R UP after linearization processing and the temperature is as Figure 5 shown. From Figure 5 it can be known that the fitting degree between the resistance value after linearization and the ideal linear straight line is better.

[0036] According to one aspect of the present application, the self-check power supply circuit realizes the DC power supply for all active devices in the self-check circuit. The self-check power supply circuit is required to have an enable control signal (Power_EN), and Power_EN is generally a TTL logic level, which is used to control the power supply on or off of the self-check circuit. There are two main purposes: one is to save the system power consumption by turning off the power supply of the self-check circuit in the non-self-check state; the other is to reduce the microwave spurious components introduced by the operation of the voltage-controlled oscillator in the non-self-check state. The self-check power supply circuit is internally composed of a linear voltage regulator or a switching voltage regulator, and outputs a stable DC power supply voltage: the output voltage VCC supplied to the voltage-controlled oscillator, the temperature compensation circuit and the microwave modulator, and the output voltage VEE supplied to the microwave switch. The TTL control signals include the enable control signal Power_EN, the pulse modulation control signal MOD, and the switch selection control signal Kn, and these control signals all come from the upper computer of the microwave system to realize the state control of the microwave self-check circuit.

[0037] According to one aspect of the present application, a microwave fixed attenuator with a large attenuation value such as 20 dB is first connected to the output end of the voltage-controlled oscillator, and the purpose is to reduce the load pulling effect of the output frequency of the voltage-controlled oscillator. Due to the presence of the pulse modulator in the microwave self-check channel, the microwave load impedance seen from the oscillator will change during the microwave modulation operation. Adding a fixed attenuator with a large attenuation value between the voltage-controlled oscillator and the modulator can eliminate the change in the output frequency of the voltage-controlled oscillator caused by the change in the load impedance. In addition, a microwave amplifier with a high isolation degree (isolation degree > 40 dB) can also be connected to the output end of the voltage-controlled oscillator to eliminate the load pulling effect.

[0038] According to one aspect of the present application, the microwave modulator is realized by connecting multiple GaAs FET process switches in series. It is required that the turn-on and turn-off times of the switch for microwave signals are < 30 ns, and the modulation depth depends on the system index requirements. Usually, a three-stage switch series form is adopted to achieve a modulation depth of > 110 dB.

[0039] According to one aspect of the present application, the microwave switch is composed of a single-pole single-throw switch, which selects to perform self-check on the microwave channel to be measured under the action of the switch signal Kn; the microwave switch is realized by using a GaAs FET process switch. It is required that the turn-on and turn-off times of the switch for microwave pulse signals are < 30 ns, and the isolation degree of the switch for microwave pulse signals is > 40 dB.

[0040] According to one aspect of the present application, the microwave filter, microwave switch, microwave power divider and directional coupler adopt the form of bare chips, and the implementation process adopts micro-assembly plus laser sealing to ensure the airtightness requirements of the self-check circuit. All devices use domestic components, which can further improve the system integration and realize the miniaturization of the self-check circuit.

[0041] The temperature compensation circuit of the voltage-controlled oscillator in the present application is simple and effective. Without increasing the circuit complexity and cost, the purpose of stabilizing the output frequency of the voltage-controlled oscillator is achieved. At the same time, the main components in the voltage-controlled oscillation circuit for microwave channel self-check all adopt bare chips, which is especially suitable for electronic countermeasure equipment with multiple microwave channels, and realizes the miniaturization and integration requirements of the equipment.

[0042] According to one aspect of the present application, the thermistor can also adopt a positive temperature coefficient (PTC) thermistor.

[0043] In an embodiment of the present application, the fixed attenuator model is IFA-20B, and the 20 dB deep attenuation is used for the load pulling effect of a smaller oscillator. The microwave filter model is HGC170-30, which is used to filter out the fundamental wave and extract the 36 GHz self-check microwave signal. The microwave modulator is realized by connecting multiple ISW-0050ST-N-PD microwave switches in series to achieve a modulation depth of > 110 dB. The power divider selects at least 1 IPD-18403 to realize the output of multiple groups of self-check signals. The directional coupler model is IDC-185020, which is used to feed the microwave self-check signal into the microwave channel.

[0044] In an embodiment of the present application, when the voltage-controlled oscillator does not have a temperature compensation circuit added, the frequency change is 635 MHz at -55°C to +85°C; after the temperature compensation circuit is added, the frequency change is 80 MHz at -55°C to +85°C. A temperature compensation circuit is introduced at the tuning power supply terminal of the voltage-controlled oscillator to solve the problem of large temperature drift of the self-check signal output by the voltage-controlled oscillator. Currently, for the Ka band such as 36 GHz, the temperature drift can be controlled within 80 MHz at -55°C to +85°C, improving the consistency and repeatability of microwave channel detection. The temperature compensation circuit is implemented by simple temperature compensation (NTC) resistor voltage division, and the complexity and cost of the circuit are relatively low.

[0045] It should be noted that, for the various specific technical features described in the above specific embodiments, they can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present utility model will not separately describe various possible combination methods.

Claims

1. A temperature-compensated voltage-controlled oscillator circuit for microwave channel self-test, characterized in that: include: A self-checking power supply circuit is used to output a stable DC power supply voltage, including an output voltage VCC and an output voltage VEE; A temperature compensation circuit is connected to the output voltage VCC of the self-test power supply circuit and is used to output a tuning voltage Vt; A voltage-controlled oscillator, wherein a power supply end of the voltage-controlled oscillator is connected to an output voltage VCC of a self-test power supply circuit, and a voltage tuning end of the voltage-controlled oscillator is connected to a tuning voltage Vt of a voltage-dividing output end of a temperature compensation circuit, for outputting a microwave continuous wave signal; A microwave modulation circuit receives a microwave continuous wave signal output by a voltage-controlled oscillator and generates a microwave pulse signal; A microwave switch is connected to the output voltage VEE of the self-test power supply circuit, receives the microwave pulse signal generated by the microwave modulation circuit through the power divider, and is used to select the microwave pulse self-test signal; The feeding coupling circuit receives the microwave pulse self-test signal selected by the microwave switch and is used to feed the microwave pulse self-test signal into the microwave channel.

2. The temperature-compensated voltage-controlled oscillator circuit for microwave channel self-test according to claim 1, characterized in that: The self-test power supply circuit includes a linear regulator or a switching regulator and is provided with an enable control signal.

3. The temperature-compensated voltage-controlled oscillator circuit for microwave channel self-test according to claim 2, characterized in that: The temperature compensation circuit uses a thermistor and an ordinary resistor in parallel and series to form a voltage divider network, and obtains the tuning voltage Vt through the voltage divider network.

4. The temperature-compensated voltage-controlled oscillator circuit for microwave channel self-test according to claim 3, characterized in that: The voltage divider network includes a thermistor R T , the first common resistor R P , the second common resistor R S , the third common resistor R dn , where the thermistor R T and the first common resistor R P One end of the thermistor R is connected to the output voltage VCC of the self-test power supply circuit. T and the first common resistor R P The other end is connected to the second common resistor R S One end of the second common resistor R S The other end is connected to the third common resistor R dn One end of the third common resistor R dn The other end is grounded.

5. The temperature-compensated voltage-controlled oscillator circuit for microwave channel self-test according to claim 1, characterized in that: The microwave modulation circuit includes a fixed attenuator, a microwave filter and a microwave modulator. The microwave continuous wave signal output by the voltage-controlled oscillator is connected to the microwave filter after passing through the fixed attenuator to output a microwave signal. The microwave signal is connected to the microwave modulator, and the microwave modulator is connected to the output voltage VCC of the self-test power supply circuit. The microwave modulator generates a microwave pulse signal with a predetermined pulse width and period under the action of the microwave signal and the preset modulation signal.

6. The temperature-compensated voltage-controlled oscillator circuit for microwave channel self-test according to claim 5, characterized in that: The microwave modulator is composed of a predetermined number of GaAs FET process switches connected in series, and the modulation depth of the microwave modulator is greater than 110 dB.

7. The temperature-compensated voltage-controlled oscillator circuit for microwave channel self-test according to claim 1, characterized in that: The microwave switch is composed of a predetermined number of single-pole single-throw switches. The opening and closing time of the microwave switch to the microwave pulse signal is less than 30ns, and the isolation degree of the microwave switch to the microwave pulse signal is greater than 40dB.

8. The temperature-compensated voltage-controlled oscillator circuit for microwave channel self-test according to claim 1, characterized in that: The feed coupling circuit includes a predetermined number of directional couplers.

9. The temperature-compensated voltage-controlled oscillator circuit for microwave channel self-test according to claim 5, characterized in that: The microwave modulation circuit also includes a microwave amplifier.

10. The temperature-compensated voltage-controlled oscillator circuit for microwave channel self-test according to claim 3, characterized in that: The thermistor is a negative temperature coefficient thermistor or a positive temperature coefficient thermistor.

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