Ultra-wideband impulse fuze random frequency modulation system and method

Abstract

The invention provides an ultra-wideband impulse fuze random frequency modulation system and method, and belongs to the technical field of ultra-wideband impulse fuzes. The system comprises a microprocessor, and a signal transmitting module and a signal receiving module which are electrically connected with the microprocessor, wherein the signal transmitting module and the signal receiving module are both electrically connected with an ultra-wideband antenna. According to the method, random modulation of the pulse repetition frequency of the ultra-wideband impulse fuze is realized through a voltage-controlled oscillation circuit based on a variable capacitance diode, and the problem of range ambiguity of the pulse fuze is solved on the basis of ensuring high repetition frequency of fuze detection sensitivity. The circuit of the system is simple, the cost is low, the mutual winding influence of fuses is reduced, and the safety and the reliability of the ultra-wideband impulse fuses under the condition of simultaneous shooting and continuous shooting are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ultra-wideband impulse fuze, and particularly relates to an ultra-wideband impulse fuze random frequency modulation system and method. BACKGROUND

[0002] The ultra-wideband impulse fuze has good anti-interference and anti-stealth capabilities, and has the advantages of good distance consistency and high reliability, and has become the mainstream working system of radio fuze.

[0003] In order to adapt to targets with different sizes of scattering cross sections, the sensitivity of the ultra-wideband impulse fuze needs to be improved, but the existing technical solutions for improving the sensitivity of the ultra-wideband impulse fuze have the problems of high cost and distance ambiguity.

[0004] In addition, in the battlefield use environment condition of salvo and continuous firing, the mutual winding influence of the fuze needs to be reduced, and the existing technical solutions have the problem of high cost. SUMMARY

[0005] The present application provides an ultra-wideband impulse fuze random frequency modulation system and method, which realizes random frequency modulation of the ultra-wideband pulse signal output by the ultra-wideband impulse fuze through a voltage-controlled oscillation circuit based on a varactor diode, solves the distance ambiguity problem while ensuring the sensitivity of the ultra-wideband impulse fuze, and has simple circuit, low cost and improved reliability of the ultra-wideband impulse fuze.

[0006] In order to achieve the above purpose, the present application adopts the following technical solutions: In a first aspect, the present application provides an ultra-wideband impulse fuze random frequency modulation system, comprising a microprocessor, a signal transmitting module and a signal receiving module electrically connected with the microprocessor, and the signal transmitting module and the signal receiving module are electrically connected with an ultra-wideband antenna. An initial signal generating module and a received signal processing module are arranged in the microprocessor. The signal transmitting module comprises a smoothing filter circuit, an adder, a noise generating circuit, a voltage-controlled oscillation circuit and a first narrow pulse generating circuit; wherein the input end of the smoothing filter circuit is electrically connected with the output end of the initial signal generating module; the adder is provided with a first input end, a second input end and an output end, the output end of the smoothing filter circuit is electrically connected with the first input end of the adder, and the second input end of the adder is electrically connected with the output end of the noise generating circuit; the voltage-controlled oscillation circuit is used for modulating the signal frequency, and the voltage-controlled oscillation circuit is provided with an input end, a first output end and a second output end; the input end of the voltage-controlled oscillation circuit is electrically connected with the output end of the adder, and the first output end of the voltage-controlled oscillation circuit is electrically connected with the input end of the first narrow pulse generating circuit; the second output end of the voltage-controlled oscillation circuit is electrically connected with the input end of the delay circuit; a varactor is further arranged in the voltage-controlled oscillation circuit; and the output end of the first narrow pulse generating circuit is electrically connected with the input end of the ultra-wideband antenna. The signal receiving module comprises a delay circuit, a second narrow pulse generating circuit and an equivalent sampling circuit; wherein the output end of the delay circuit is electrically connected with the input end of the second narrow pulse generating circuit; the equivalent sampling circuit is provided with a first input end, a second input end and an output end, the first input end of the equivalent sampling circuit is electrically connected with the output end of the second narrow pulse generating circuit, and the second input end of the equivalent sampling circuit is electrically connected with the output end of the ultra-wideband antenna; and the output end of the equivalent sampling circuit is electrically connected with the input end of the received signal processing module.

[0007] In an implementation form of the first aspect, the voltage-controlled oscillation circuit is composed of an inductor, an inverter, a capacitor, the varactor and a resistor which are electrically connected in sequence.

[0008] In an implementation form of the first aspect, the initial signal generating module comprises a signal generating unit and a digital-to-analog converter. The input end of the initial signal generating module is electrically connected with the output end of a control unit in the microprocessor, the input end of the signal generating unit is coupled with the input end of the initial signal generating module, the output end of the signal generating unit is electrically connected with the input end of the digital-to-analog converter, and the output end of the digital-to-analog converter is coupled with the output end of the initial signal generating module.

[0009] In an implementation form of the first aspect, the initial signal generated by the signal generating unit is a random noise signal or a standard waveform signal.

[0010] In an implementation form of the first aspect, the receiving signal processing module comprises an amplification filter and a signal decision unit. An input of the amplification filter is coupled to the input of the receiving signal processing module, an output of the amplification filter is electrically connected to an input of the signal decision unit, and an output of the signal decision unit is electrically connected to the output of the receiving signal processing module.

[0011] In an implementation form of the first aspect, the noise generating circuit is composed of multiple operational amplifiers.

[0012] In an implementation form of the first aspect, the delay circuit is composed of multiple logic chips connected in series.

[0013] In the second aspect, the application provides a random frequency modulation method of an ultra-wideband impulse fuze, based on the system of the first aspect, comprising: an initial signal generating module in the microprocessor generates an initial signal of an ultra-wideband pulse signal; a noise generating circuit generates a noise signal. A smoothing filter circuit in the signal transmitting module outputs a smoothing filter signal after smoothing filter processing of the initial signal; an adder receives the noise signal and the smoothing filter signal, and outputs a composite signal after merging the noise signal and the smoothing filter signal; a varactor in the voltage-controlled oscillation circuit outputs a frequency modulation signal after frequency modulation of the composite signal; a first narrow pulse generating circuit outputs an ultra-wideband pulse signal after processing of the frequency modulation signal. An ultra-wideband antenna transmits the ultra-wideband pulse signal; the ultra-wideband antenna receives an ultra-wideband pulse signal reflected by a target object. A delay circuit of the signal receiving module outputs a delay signal after delay processing of the frequency modulation signal; a second narrow pulse generating circuit outputs a delay pulse signal after processing of the delay signal; an equivalent sampling circuit outputs a detection signal after equivalent sampling of the reflected ultra-wideband pulse signal and the delay pulse signal. A receiving signal processing module in the microprocessor judges the detection signal and gives a near-explosion start signal.

[0014] In an implementation form of the second aspect, the initial signal of the ultra-wideband pulse signal is generated, comprising: a control unit in the microprocessor sends a signal generation instruction to a signal generating unit in the initial signal generating module. The signal generating unit generates the initial signal; a digital-to-analog converter outputs the initial signal of the ultra-wideband pulse signal after digital-to-analog conversion of the initial signal.

[0015] In an implementation form of the second aspect, the detection signal is judged and the near-explosion start signal is given, comprising: an amplification filter in the receiving signal processing module outputs an amplified signal after amplification of the detection signal; a signal decision unit judges the amplified signal, and outputs the near-explosion start signal when the amplified signal meets the echo characteristics of the target object.

[0016] Compared with the prior art, the application has the following beneficial effects.

[0017] This invention provides a random frequency modulation system for an ultra-wideband impulse fuze. An initial signal is generated by an initial signal generation module within a microprocessor, and then smoothed by a smoothing filter circuit to obtain a smoothed filter signal. The smoothed filter signal and a noise signal generated by a noise generation circuit are input into a voltage-controlled oscillator circuit based on a varactor diode. Since the smoothed filter signal can cover the reverse bias voltage signal range of the varactor diode, although the smoothed filter signal is limited by the update rate of the initial signal generation module and is difficult to adjust between each clock cycle (approximately on the order of hundreds of nanoseconds) of the ultra-wideband impulse fuze, the noise signal simultaneously compensates for the slow update rate of the smoothed filter signal. This achieves random frequency modulation of the ultra-wideband pulse signal output by the ultra-wideband impulse fuze. The time of each clock cycle of the ultra-wideband impulse fuze continuously changes, solving the distance ambiguity problem of the pulse fuze while ensuring high repetition rate detection sensitivity. The system has a simple circuit, low cost, and reduces the influence of fuze intertwining, improving the reliability and safety of the ultra-wideband impulse fuze. Attached Figure Description

[0018] Figure 1 This is one of the schematic diagrams of an ultra-wideband impulse fuze random frequency modulation system provided in the embodiments of this application; Figure 2 This is a second schematic diagram of an ultra-wideband impulse fuze random frequency modulation system provided in the embodiments of this application; Figure 3 This is the third schematic diagram of an ultra-wideband impulse fuze random frequency modulation system provided in the embodiments of this application; Figure 4 This is the fourth schematic diagram of an ultra-wideband impulse fuze random frequency modulation system provided in the embodiments of this application; Figure 5 This is a circuit diagram of the amplification filter in the ultra-wideband impulse fuze random frequency modulation system provided in the embodiments of this application; Figure 6 This is the fifth schematic diagram of an ultra-wideband impulse fuze random frequency modulation system provided in the embodiments of this application.

[0019] Figure 7 This is a schematic diagram of the smoothing filter circuit in the ultra-wideband impulse fuze random frequency modulation system provided in the embodiments of this application; Figure 8 This is a circuit diagram of the adder in the ultra-wideband impulse fuze random frequency modulation system provided in the embodiments of this application; Figure 9 This is a schematic diagram of the noise generation circuit in the ultra-wideband impulse fuze random frequency modulation system provided in the embodiments of this application; Figure 10 This is a schematic diagram of the voltage-controlled oscillator circuit in the ultra-wideband impulse fuze random frequency modulation system provided in the embodiments of this application; Figure 11 This is a schematic diagram of the first narrow pulse generation circuit or the second narrow pulse generation circuit provided in the embodiments of this application; Figure 12 This is the sixth schematic diagram of an ultra-wideband impulse fuze random frequency modulation system provided in the embodiments of this application; Figure 13 This is a schematic diagram of the delay circuit in the ultra-wideband impulse fuze random frequency modulation system provided in the embodiments of this application; Figure 14 This is a schematic diagram of the equivalent sampling circuit in the ultra-wideband impulse fuze random frequency modulation system provided in the embodiments of this application; Figure 15 This is one of the schematic diagrams of a random frequency modulation method for an ultra-wideband impulse fuze provided in the embodiments of this application; Figure 16 This is the second schematic diagram of a random frequency modulation method for an ultra-wideband impulse fuze provided in the embodiments of this application. Detailed Implementation

[0020] In the specification and claims of this invention, the terms "first" and "second," etc., are used to distinguish different objects, rather than to describe a specific order of objects.

[0021] In the embodiments of this application, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or design that is described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design. Specifically, the use of the terms "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0022] In the prior art described in the background section, to improve the sensitivity of ultra-wideband impulse fuses, a high repetition rate (PRF) design is generally used to increase the number of pulse accumulations, thereby improving the processing gain. However, the high PRF design can cause range ambiguity problems. Traditional ultra-wideband fuses use pulse position modulation to resolve range ambiguity, where the pulse position modulation signal generally uses a pseudo-random code. Additionally, there are reports of using circuit noise control of the phase of direct digital frequency synthesis (DDS) to achieve truly random pulse position modulation.

[0023] Both the pulse signal based on pseudo-random code modulation and the DDS phase control based on true random numbers employ a field-programmable gate array (FPGA) processor. FPGAs are power-hungry and expensive, making them difficult to apply to conventional fuses where energy and cost are strictly limited.

[0024] To address the aforementioned issues, this application provides a random frequency modulation system and method for ultra-wideband impulse fuzes. This embodiment utilizes varactor diodes to achieve random frequency modulation, resulting in a simple circuit structure, low cost, and the ability to be mass-produced and applied to conventional fuzes. Random frequency modulation causes the repetition period of the ultra-wideband pulse signal emitted by the ultra-wideband impulse fuze to continuously change, resolving the distance ambiguity problem of pulse fuzes. Furthermore, during salvo or continuous firing, the emission signal periods of different fuzes differ, reducing mutual interference and improving the reliability and safety of the fuze operation.

[0025] like Figure 1 As shown in the embodiment of this application, an ultra-wideband impulse fuze random frequency modulation system includes a microprocessor (MCU), a signal transmitting module and a signal receiving module electrically connected to the microprocessor, and both the signal transmitting module and the signal receiving module are electrically connected to an ultra-wideband antenna.

[0026] It should be noted that in an ultra-wideband impulse fuze random frequency modulation system, if one of the components has only one input and one output, the input and output of that component will not be described.

[0027] Optionally, such as Figure 2 As shown, the microprocessor described above includes an initial signal generation module and a receiving signal processing module.

[0028] Understandably, in the aforementioned ultra-wideband impulse fuze random frequency modulation system, the initial signal generation module in the microprocessor is used to generate the initial signal of the ultra-wideband pulse signal; the signal transmission module processes the initial signal and then transmits the processed ultra-wideband pulse signal through the ultra-wideband antenna; after the ultra-wideband antenna receives the ultra-wideband pulse signal reflected by the target object, the signal receiving module processes the reflected ultra-wideband pulse signal and outputs it to the receiving signal processing module; the receiving signal processing module judges the processed ultra-wideband pulse signal, and outputs a proximity trigger signal when the processed ultra-wideband pulse signal matches the echo characteristics of the target object.

[0029] like Figure 3 As shown below, the initial signal generation module will be further explained.

[0030] The aforementioned initial signal generation module includes a signal generation unit and a digital-to-analog converter (DAC). The input terminal of the initial signal generation module is electrically connected to the output terminal of the control unit in the microprocessor; the input terminal of the signal generation unit is coupled to the input terminal of the initial signal generation module; the output terminal of the signal generation unit is electrically connected to the input terminal of the DAC; and the output terminal of the DAC is coupled to the output terminal of the initial signal generation module.

[0031] In this embodiment, the initial signal generated by the signal generation unit is a random noise signal or a standard waveform signal (such as sine waves, sawtooth waves, triangular waves, and other standard waveform signals of different styles). The random noise signal can be generated by a hardware random number generator (RNG); the standard waveform signal can be generated by a function generator or an arbitrary waveform generator. Therefore, the signal generation unit can include a hardware random number generator and a function generator / arbitrary waveform generator. It is understood that the hardware random number generator generates true random numbers, i.e., noise signals, based on a thermal noise physical random source, and has the characteristics of complete randomness and high-speed generation. Since the aforementioned digital-to-analog converter hardware random number generator and function generator / arbitrary waveform generator are commonly used signal generation devices in this technical field, this embodiment does not elaborate on the devices and connection methods included in the signal generation unit.

[0032] Combination Figure 3 ,like Figure 4 As shown, the above-mentioned receiving signal processing module includes an amplification filter and a signal decision unit. The input terminal of the amplification filter is coupled to the input terminal of the receiving signal processing module, the output terminal of the amplification filter is electrically connected to the input terminal of the signal decision unit, and the output terminal of the signal decision unit is electrically connected to the output terminal of the receiving signal processing module.

[0033] Understandably, the aforementioned amplification filter is a piece of physical hardware, and its circuit diagram can be seen as follows: Figure 5 As shown. Reference Figure 5 The amplification and filtering circuit consists of an operational amplifier and external resistors and capacitors. Figure 5 The amplifier and filter circuit shown is a 6th-order low-pass filter circuit.

[0034] The aforementioned signal decision unit is software logic and is stored in the microprocessor's memory space. The decision logic of the aforementioned signal decision unit is as follows: determine whether the ultra-wideband pulse signal output by the amplification filter matches the echo characteristics of the target object. When the ultra-wideband pulse signal output by the amplification filter matches the echo characteristics of the target object, output a proximity trigger signal.

[0035] Combination Figure 4 ,like Figure 6 As shown, the signal transmission module includes: a smoothing filter circuit, an adder, a noise generation circuit, a voltage-controlled oscillator circuit, and a first narrow pulse generation circuit.

[0036] The following is a further explanation of each component in the above signal transmission module.

[0037] The input terminal of the aforementioned smoothing filter circuit is coupled to the input terminal of the aforementioned signal transmission module, and the input terminal of the smoothing filter circuit is electrically connected to the output terminal of the initial signal generation module. Optionally, the aforementioned smoothing filter circuit can be as follows: Figure 7 As shown. Reference Figure 7 The smoothing filter circuit consists of an operational amplifier and external resistors and capacitors. Figure 7 The smoothing filter circuit shown is a second-order low-pass filter circuit.

[0038] The adder described above has a first input terminal, a second input terminal, and an output terminal. The output terminal of the smoothing filter circuit is electrically connected to the first input terminal of the adder, and the second input terminal of the adder is electrically connected to the output terminal of the noise generation circuit. Optionally, the adder can be configured as follows: Figure 8 As shown. Reference Figure 8 The adder consists of an operational amplifier and external resistors and capacitors. The channel gain of the two adders can be set by selecting the resistance value.

[0039] The noise generation circuit described above consists of multiple operational amplifier stages. For example, the circuit diagram of the noise generation circuit can be shown as follows: Figure 9 As shown. Specifically, Figure 9 The circuit shown is a three-stage differential amplifier circuit composed of four operational amplifiers. Its function is to amplify the thermal noise of the resistors step by step. Its gain is very high, and the amplification gain can be flexibly set by the resistors.

[0040] The voltage-controlled oscillator circuit described above has an input terminal, a first output terminal, and a second output terminal. The input terminal of the voltage-controlled oscillator circuit is electrically connected to the output terminal of the adder, and the first output terminal of the voltage-controlled oscillator circuit is electrically connected to the input terminal of the first narrow pulse generation circuit. The second output terminal of the voltage-controlled oscillator circuit is electrically connected to the input terminal of the delay circuit.

[0041] Specifically, the voltage-controlled oscillator circuit described above is used to modulate the signal frequency, and a varactor diode is incorporated within the voltage-controlled oscillator circuit. Optionally, refer to... Figure 10 The aforementioned voltage-controlled oscillator circuit consists of an inductor, an inverter, a capacitor, a varactor diode, and a resistor connected in sequence. The varactor diode and resistor form an RC oscillation feedback loop, while the inductor and capacitor provide isolation. The inductor is approximately short-circuited for low-frequency voltage signals and approximately open-circuited for high-frequency oscillation circuitry, thus preventing the high-frequency oscillation signal from affecting the low-frequency voltage-controlled signal (i.e., the reverse bias voltage signal). Similarly, the capacitor is approximately open-circuited for low-frequency voltage signals and approximately short-circuited for high-frequency oscillation circuitry, thus preventing the low-frequency voltage-controlled signal from affecting the high-frequency oscillation signal.

[0042] The output terminal of the aforementioned first narrow pulse generation circuit is electrically connected to the input terminal of the ultra-wideband antenna. The aforementioned first narrow pulse generation circuit can be configured as follows: Figure 11 As shown. Reference Figure 11The first narrow pulse generating circuit consists of a step recovery diode and an external inductor and capacitor connected in sequence.

[0043] like Figure 12 As shown, the signal receiving module includes: a delay circuit, a second narrow pulse generation circuit, and an equivalent sampling circuit.

[0044] The following is a further explanation of each component in the above signal receiving module.

[0045] The input terminal of the aforementioned delay circuit is electrically connected to the second output terminal of the aforementioned voltage-controlled oscillator circuit, and the output terminal of the aforementioned delay circuit is electrically connected to the input terminal of the second narrow pulse generation circuit. Optionally, the aforementioned delay circuit is composed of multiple sequentially electrically connected logic chips, and the aforementioned delay circuit can be as follows: Figure 13 As shown.

[0046] The equivalent sampling circuit described above has a first input terminal, a second input terminal, and an output terminal. The first input terminal of the equivalent sampling circuit is electrically connected to the output terminal of the second narrow pulse generation circuit, and the second input terminal of the equivalent sampling circuit is electrically connected to the output terminal of the ultra-wideband antenna. The output terminal of the equivalent sampling circuit is electrically connected to the input terminal of the received signal processing module.

[0047] Alternatively, the above-mentioned second narrow pulse generation circuit can also be as follows: Figure 11 As shown. Figure 14 As shown, the equivalent sampling circuit described above can be composed of a mixer diode and an external integrating and differentiating resistor-capacitor circuit.

[0048] Correspondingly, such as Figure 15 As shown, this application provides a method for random frequency modulation of an ultra-wideband impulse fuze, including steps S101-S105.

[0049] S101, the initial signal generation module in the microprocessor generates the initial signal of the ultra-wideband pulse signal; the noise generation circuit generates the noise signal.

[0050] Optionally, combined Figure 15 ,like Figure 16 As shown, S101 includes S1011-S1012.

[0051] S1011. Send a signal generation command to the signal generation unit in the initial signal generation module.

[0052] It is understood that the above signal generation instructions can be generated by the control unit within the microprocessor or by other controllers. The object that generates the above signal generation instructions is not limited in the embodiments of this application.

[0053] S1012, The signal generation unit generates an initial signal; the digital-to-analog converter performs digital-to-analog conversion on the initial signal and outputs the initial signal of the ultra-wideband pulse signal.

[0054] S102, the smoothing filter circuit in the signal transmission module performs smoothing filter processing on the initial signal and outputs a smoothed filter signal; the adder receives the noise signal and the smoothed filter signal, and combines the noise signal and the smoothed filter signal to output a composite signal; the varactor diode in the voltage-controlled oscillator circuit performs frequency modulation on the composite signal and outputs a frequency-modulated signal; the first narrow pulse generation circuit processes the frequency-modulated signal and outputs an ultra-wideband pulse signal.

[0055] S103, the ultra-wideband antenna transmits ultra-wideband pulse signals; the ultra-wideband antenna receives ultra-wideband pulse signals reflected by the target object.

[0056] S104, the delay circuit of the signal receiving module receives the frequency modulation signal, performs delay processing, and outputs the delayed signal; the second narrow pulse generation circuit processes the delayed signal and outputs the delayed pulse signal; the equivalent sampling circuit receives the ultra-wideband pulse signal and the delayed pulse signal obtained by reflection, performs equivalent sampling, and outputs the detection signal.

[0057] S105, the receiving signal processing module in the microprocessor determines the detection signal and provides a proximity trigger signal.

[0058] For example, S105 above includes S1051.

[0059] S1051, the amplification filter in the receiving signal processing module amplifies the detector signal and outputs an amplified signal; the signal decision unit judges the amplified signal, and outputs a proximity trigger signal when the amplified signal matches the echo characteristics of the target object.

[0060] In one implementation, the process of the above-mentioned ultra-wideband impulse fuze random frequency modulation method is as follows.

[0061] (1) The resistors and capacitors of the voltage-controlled oscillator circuit are obtained based on the pulse repetition frequency (PRF) range of the ultra-wideband impulse fuze.

[0062] Where K is a coefficient related to the inverter, typically between 0.8 and 1.4, and is taken as 1.0 in the calculation; R is the oscillation resistance, typically between 2kΩ and 10kΩ, and is taken as 6.8kΩ; C is the oscillation capacitor. For example, assuming the ultra-wideband impulse fuze pulse repetition frequency PRF is 10MHz, then C = 14.7pF can be calculated using the above formula.

[0063] (2) Obtain the reverse bias voltage of the varactor diode based on the oscillation capacitor.

[0064] When the oscillation capacitor includes the varactor diode junction capacitance, inverter pin parasitic capacitance, and circuit board trace parasitic capacitance, etc., assuming that except for the varactor diode junction capacitance, the other capacitances C o =3pF, then the junction capacitance C of the varactor diode d = CC o =11.7pF.

[0065] Consult the varactor diode datasheet to obtain the reverse bias voltage V of the varactor diode. R For example, the junction capacitance C of a varactor diode. d When the value is 11.7 pF, the corresponding V R ≈7.5V. It should be understood that the above varactor diode datasheet is prior art, and this application will not elaborate on the contents of the above varactor diode datasheet in its embodiments.

[0066] (3) Determine the diode reverse bias voltage range according to the frequency modulation range and the steps (1) to (2).

[0067] Frequency modulation range is denoted as PRF min ~PRF max Then the junction capacitance C of the varactor diode dmin ~C dmax have: For example, frequency modulation range (PRF) min ~PRF max Select a frequency of 8MHz to 12MHz, and substitute the parameters to obtain the varactor diode junction capacitance C. dmin ~C dmax The value ranges from 9.3pF to 15.4pF. Referring to the varactor diode datasheet, the reverse bias voltage V of the varactor diode is obtained. R The voltage range is 5.1V to 9.0V.

[0068] (4) Determine the parameters of the smoothing filter circuit in the signal transmission module and the output voltage range of the DAC in the microprocessor.

[0069] The microprocessor's internal DAC output voltage dynamic range is 0–3.3Vpp, therefore the DAC's direct output voltage needs to be adjusted to the voltage range required by the varactor diode. Additionally, to reduce the influence of the oscillation circuit on the DAC output signal, an active analog filter circuit is used to isolate the oscillation circuit and the DAC output circuit. This active filter simultaneously filters out high-frequency components in the DAC signal, acting as a smoothing filter. The smoothing filter uses a second-order active low-pass filter, and the filter gain can be set to A. p =4 times, filter cutoff frequency settingf c It is 150kHz.

[0070] Among them, the filter gains are: The filter cutoff frequencies are: In actual circuits, =1.8kΩ, =7.5kΩ, =1.5kΩ, =100pF, =1nF, Vref=7.0V. Substituting into the formula, we get A p =4.17, f c =150kHz.

[0071] Let the DAC output voltage range be denoted as... ~ Then we have: In actual circuits, =5.1V, Substituting =9.0V, we get... =1.194V, =2.130V. That is, the DAC output voltage range is 1.194V to 2.130V.

[0072] f c / 1.5, where the value is 100ksps.

[0073] (5) The noise signal and the smoothing filter signal together constitute the reverse bias voltage signal of the varactor diode.

[0074] The smoothing filter signal can cover the reverse bias voltage signal range of the varactor diode. At the same time, the DAC can output various waveforms such as random noise, sine wave, sawtooth wave, and triangular wave. However, due to the limitation of the DAC update rate, it is difficult to adjust between each clock cycle (about 100 nanoseconds) of the ultra-wideband fuze. Therefore, it is necessary to use noise signal to make up for the slow update rate of the smoothing filter signal.

[0075] The noise generation circuit consists of multiple operational amplifier stages. The noise signal includes operational amplifier voltage noise, current noise, and resistor thermal noise. The amplification factor is adjusted according to the noise level to amplify the noise to a certain order of magnitude, compensating for the insufficient signal update rate after DAC smoothing and filtering. It should be understood that the dynamic range of the noise generation circuit's output signal should not exceed the dynamic range of the varactor diode's reverse bias voltage signal. Here, we can take 1 / 4 of the varactor diode's reverse bias voltage signal dynamic range, i.e., the output signal U of the noise amplifier circuit. n Peak-to-peak value =0.975V.

[0076] The noise signal and the smoothed filtered signal are respectively input to the adder, meaning the voltage of the composite signal output by the adder satisfies: When designing a circuit, you can take ,therefore = .

[0077] Therefore, the peak-to-peak value of the varactor diode reverse bias voltage signal is: 9.0 - 5.1 + 0.945 = 4.875. That is, the voltage range of the noise signal output by the noise generation circuit is 5.513V to 6.489V, the range of the smoothing filter signal output by the microprocessor is 5.1V to 9.0V, and the range of the varactor diode reverse bias voltage signal is approximately 5.51V to 10.39V.

[0078] Referring to the varactor diode datasheet, when the reverse bias voltage signal range is approximately 5.51V to 10.39V, the junction capacitance C... d The range is 7.9 pF to 13.8 pF. Substituting... It can be seen that the pulse repetition frequency (PRF) of the ultra-wideband impulse fuze ranges from 8.75MHz to 13.5MHz.

[0079] (6) The frequency modulation signal is amplified by radio frequency or radiated directly by the ultra-wideband antenna; the frequency modulation signal with position modulation is delayed by a delay circuit (this delay is the setting of the high voltage, which is composed of several logic chips), and then the delayed pulse signal is obtained by the second narrow pulse generation circuit.

[0080] (7) The ultra-wideband pulse signal sent by the fuze through the ultra-wideband antenna is scattered by the target object and then received by the ultra-wideband antenna again. This signal and the delayed pulse signal are received by the equivalent sampling circuit and output as a detector signal.

[0081] (8) After the detection signal is amplified, filtered and judged, a proximity start signal is output after it meets the target echo characteristics.

Claims

1. An ultra-wideband (UWB) burst fuze random frequency modulation system, comprising a microprocessor, a signal transmitting module and a signal receiving module electrically connected to the microprocessor, and the signal transmitting module and the signal receiving module are electrically connected to an UWB antenna; characterized in that: an initial signal generating module and a received signal processing module are arranged in the microprocessor; the signal transmitting module comprises a smoothing filter circuit, an adder, a noise generating circuit, a voltage controlled oscillation circuit and a first narrow pulse generating circuit; wherein the input end of the smoothing filter circuit is electrically connected to the output end of the initial signal generating module; the adder is provided with a first input end, a second input end and an output end, the output end of the smoothing filter circuit is electrically connected to the first input end of the adder, and the second input end of the adder is electrically connected to the output end of the noise generating circuit; the voltage controlled oscillation circuit is used for modulating signal frequency, and the voltage controlled oscillation circuit is provided with an input end, a first output end and a second output end; the input end of the voltage controlled oscillation circuit is electrically connected to the output end of the adder, the first output end of the voltage controlled oscillation circuit is electrically connected to the input end of the first narrow pulse generating circuit; the second output end of the voltage controlled oscillation circuit is electrically connected to the input end of a delay circuit; a varactor is further arranged in the voltage controlled oscillation circuit; the output end of the first narrow pulse generating circuit is electrically connected to the input end of the UWB antenna; the signal receiving module comprises the delay circuit, a second narrow pulse generating circuit and an equivalent sampling circuit; wherein the output end of the delay circuit is electrically connected to the input end of the second narrow pulse generating circuit; the equivalent sampling circuit is provided with a first input end, a second input end and an output end, the first input end of the equivalent sampling circuit is electrically connected to the output end of the second narrow pulse generating circuit, and the second input end of the equivalent sampling circuit is electrically connected to the output end of the UWB antenna; the output end of the equivalent sampling circuit is electrically connected to the input end of the received signal processing module.

2. The system according to claim 1, characterized in that: the voltage controlled oscillation circuit is composed of an inductor, an inverter, a capacitor, the varactor and a resistor which are electrically connected in sequence.

3. The system according to claim 1, characterized in that: the initial signal generating module comprises a signal generating unit and a digital-to-analog converter; the input end of the initial signal generating module is electrically connected to the output end of a control unit in the microprocessor, the input end of the signal generating unit is coupled to the input end of the initial signal generating module, the output end of the signal generating unit is electrically connected to the input end of the digital-to-analog converter, and the output end of the digital-to-analog converter is coupled to the output end of the initial signal generating module.

4. The system according to claim 3, characterized in that: the initial signal generated by the signal generating unit is a random noise signal or a standard waveform signal.

5. The system according to claim 1 or 3, characterized in that: the received signal processing module comprises an amplification filter and a signal decision unit. ​ The input end of the amplification filter is coupled with the input end of the received signal processing module, the output end of the amplification filter is electrically connected with the input end of the signal decision unit, and the output end of the signal decision unit is electrically connected with the output end of the received signal processing module.

6. The system of claim 1, wherein, The noise generation circuit is composed of multiple stages of operational amplifiers.

7. The system of claim 1, wherein, The delay circuit is composed of multiple logically sequential chips.

8. A random frequency modulation method for an ultra-wideband impulsive fuze, based on the system of any one of claims 1 to 7, characterized in that, including: The initial signal generation module in the microprocessor generates an initial signal of an ultra-wideband pulse signal; The noise generation circuit generates a noise signal; The smoothing filter circuit in the signal transmitting module outputs a smoothing filter signal after smoothing filter processing of the initial signal; the adder receives the noise signal and the smoothing filter signal, and outputs a composite signal after merging the noise signal and the smoothing filter signal; the varactor in the voltage-controlled oscillation circuit outputs a frequency modulation signal after frequency modulation of the composite signal; and the first narrow pulse generation circuit outputs an ultra-wideband pulse signal after processing of the frequency modulation signal; The ultra-wideband antenna transmits the ultra-wideband pulse signal, and receives an ultra-wideband pulse signal reflected by a target object; The delay circuit of the signal receiving module outputs a delay signal after delay processing of the frequency modulation signal; the second narrow pulse generation circuit outputs a delay pulse signal after processing of the delay signal; and the equivalent sampling circuit outputs a detection signal after equivalent sampling of the reflected ultra-wideband pulse signal and the delay pulse signal; The received signal processing module in the microprocessor judges the detection signal and gives a near explosion start signal.

9. The method of claim 8, wherein, The initial signal of the ultra-wideband pulse signal includes: The control unit in the microprocessor sends a signal generation instruction to a signal generation unit in the initial signal generation module; The signal generation unit generates an initial signal, and the digital-to-analog converter outputs the initial signal of the ultra-wideband pulse signal after digital-to-analog conversion of the initial signal.

10. The method of claim 8, wherein, The judgment of the detection signal and the giving of the near explosion start signal include: The amplification filter in the received signal processing module outputs an amplified signal after amplification of the detection signal; and the signal decision unit judges the amplified signal, and outputs a near explosion start signal when the amplified signal meets the echo characteristics of the target object.

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