Program-controlled frequency sweep signal source circuit

Abstract

The utility model discloses a program-controlled frequency sweep signal source circuit, which comprises a sawtooth wave generator, a digital potentiometer, an MCU (Microprogrammed Control Unit) control circuit and a DAC (Digital-to-Analog Converter) circuit. The output end of the MCU control circuit is respectively connected with the input ends of the sawtooth wave generator, the digital potentiometer and the DAC circuit; the input end of the sawtooth wave generator is connected with the MCU control circuit, and the output end of the sawtooth wave generator is connected with the digital potentiometer; the input end of the digital potentiometer is respectively connected with the sawtooth wave generator and the MCU control circuit; the input end of the DAC circuit is connected with the output end of the MCU control circuit. The MCU control circuit can efficiently process parameters such as frequency sweep signal source bandwidth, frequency sweep frequency and central frequency point input from the outside and convert the parameters into internal control signals, and the highly integrated design simplifies the circuit structure and improves the reliability and stability of the system.

Description

Technical Field

[0001] The utility model belongs to the technical field of communication anti-interference and intelligent security equipment, and particularly relates to a program-controlled sweep frequency signal source circuit. Background Art

[0002] With the continuous development of wireless communication technology, a large number of wireless communication electronic products have become widely used in people's daily lives. However, the illegal use of some products has also posed safety risks to people's lives. For example, wireless communication products have been used to cheat on educational exams, and drones have been illegally entering airport airspace, causing large-scale flight delays and forced landings, seriously affecting the travel plans of many passengers. Such illegal use of radio signals requires communication countermeasures, and the use of jamming equipment to accurately and effectively suppress radio signals is essential.

[0003] The jammer is mainly composed of a jammer signal source, a power amplifier, a radio frequency antenna, etc. The jammer signal source is mainly implemented using a direct digital synthesizer (DDS) or a voltage-controlled oscillator (VCO).

[0004] Currently, digital frequency synthesis chips are used to generate baseband interference signals, but this is costly, and the bandwidth of the high-frequency interference signal output is limited by the bandwidth of the baseband interference signal, which is relatively narrow. The voltage-controlled oscillator (VCO), a key component with widespread applications, is used in traditional jamming equipment to modulate the VCO using a sawtooth wave generated by a 555 combinational circuit. The amplitude of the sawtooth wave determines the bandwidth of the swept-frequency signal source, while the frequency of the sawtooth wave determines the sweep frequency. The sawtooth wave frequency is determined by external resistors and capacitors, and its amplitude is affected by the supply voltage and cannot be controlled by an external program. Furthermore, its stability is poor, making it impossible to instantly adjust to the frequency band in the field. Therefore, the bandwidth of the high-frequency interference signal generated by these methods rarely meets the desired bandwidth, suffers from poor stability, and is not adjustable for both signal bandwidth and sweep frequency. Utility Model Content

[0005] The purpose of the invention of the utility model is to provide a programmable sweep frequency signal source circuit to solve the above-mentioned problems, hoping to improve the problem that the bandwidth, sweep frequency and center frequency of the existing sweep frequency signal source are inconvenient to adjust immediately.

[0006] The technical solution adopted by the utility model is as follows: a programmable frequency sweep signal source circuit, including a sawtooth wave generator, a digital potentiometer, an MCU control circuit and a DAC circuit; the output end of the MCU control circuit is respectively connected to the input ends of the sawtooth wave generator, the digital potentiometer and the DAC circuit, and the input end of the MCU control circuit is used to receive a control signal; the input end of the sawtooth wave generator is connected to the MCU control circuit, and the output end of the sawtooth wave generator is connected to the digital potentiometer, and the sawtooth wave generator is used to generate a sawtooth waveform signal; the input end of the digital potentiometer is respectively connected to the sawtooth wave generator and the MCU control circuit, and the digital potentiometer is used to perform voltage regulation control on the amplitude of the waveform signal generated by the sawtooth wave generator; the input end of the DAC circuit is connected to the output end of the MCU control circuit, and the MCU control circuit sends a control signal to the DAC circuit, and the DAC circuit is used to convert the voltage digital signal into an analog voltage signal.

[0007] It should be noted that MCU stands for microcontroller, and MCU control circuit refers to the control system circuit composed of the microcontroller. DAC circuit, the full name of Digital-to-Analog Converter circuit, is an electronic device or integrated circuit that converts digital signals into analog signals.

[0008] Furthermore, the circuit also includes an AC coupler circuit, a VCO voltage-controlled oscillator and a power supply circuit; the input end of the AC coupler circuit is connected to the digital potentiometer, the output end of the AC coupler circuit is connected to the input end of the VCO voltage-controlled oscillator, and the AC coupler circuit is used to block the DC component output by the digital potentiometer; the input end of the VCO voltage-controlled oscillator is connected to the AC coupler circuit and the DAC circuit, and the VCO voltage-controlled oscillator is used to output a programmable sweep signal source; the output end of the power supply circuit is connected to the digital potentiometer, and the power supply circuit is used to provide power for the circuit.

[0009] It should be noted that the VCO voltage-controlled oscillator, full name Voltage Controlled Oscillator, its oscillation frequency can be controlled by an external voltage signal.

[0010] Furthermore, the sawtooth wave generator is a controllable signal generator using direct digital frequency synthesis technology.

[0011] Furthermore, the digital potentiometer includes a voltage divider and a controller. The voltage divider includes multiple groups of resistor elements, and the resistor elements are connected to input pins of the controller; the controller is used to read the control signal to change the resistance size in the voltage divider.

[0012] Furthermore, the input signal of the DAC circuit input end is a voltage digital signal, and the output signal of the DAC circuit output end is an analog voltage signal.

[0013] Furthermore, the output end of the AC coupler circuit is connected to the DAC circuit, and the analog voltage signal output by the DAC circuit and the sawtooth wave signal output by the AC coupler circuit are superimposed to form a VCO tuning voltage signal.

[0014] Furthermore, the VCO voltage-controlled oscillator input terminal is used to connect to the VCO tuning voltage signal, and the VCO voltage-controlled oscillator output terminal is used to output a program-controlled sweep frequency signal source.

[0015] Furthermore, the power supply circuit is an AD-DC switching circuit or a DC-DC power converter.

[0016] It should be noted that the power supply module can use some linear voltage regulation circuits.

[0017] Furthermore, the VCO voltage-controlled oscillator is used to adjust the tuning voltage within an adjustable range.

[0018] Furthermore, the control signal received by the input end of the MCU control circuit is the sweep frequency, the sweep bandwidth and the center frequency.

[0019] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0020] The MCU control circuit of the utility model can generate a high-precision sawtooth wave signal and bias voltage through calculation and control, thereby ensuring the high precision and stability of the sweep signal source. In addition, the sweep frequency, sweep bandwidth and center frequency of the sweep signal source can be set, making it more flexible to use.

[0021] The utility model proposes a programmable sweep frequency signal source circuit. The MCU control circuit can efficiently process external input sweep frequency signal source parameters such as bandwidth, sweep frequency and center frequency, and convert them into internal control signals. This highly integrated design simplifies the circuit structure and improves the reliability and stability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a functional block diagram of the program-controlled frequency sweep signal source of the present utility model;

[0023] Figure 2 This is the principle block diagram of the sawtooth wave generator of the utility model. DETAILED DESCRIPTION

[0024] The present invention will be described in detail below with reference to the accompanying drawings.

[0025] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0026] Example 1

[0027] like Figure 1 As shown, one embodiment of the present invention is a programmable frequency sweep signal source circuit, which includes a sawtooth wave generator, a digital potentiometer, an MCU control circuit, a DAC circuit, an AC coupler circuit, a VCO voltage-controlled oscillator and a power supply circuit.

[0028] The sawtooth wave generator is a controlled signal generator with controllable signal waveform frequency. The digital potentiometer adjusts the amplitude of the sawtooth wave through voltage regulation. The voltage-regulated waveform signal is then superimposed with the DC component generated by the DAC circuit through an AC coupler. This superimposed signal is then used to control the tuning input of the voltage-controlled oscillator, thereby completing the signal frequency sweep function.

[0029] The receiving end of the MCU control circuit receives the external program-controlled control signal, converts the received control signal internally, and then controls the sawtooth wave generator, digital potentiometer and DAC circuit respectively, and finally obtains the target frequency sweep signal.

[0030] A digital potentiometer, also known as a digitally controlled programmable resistor, operates by precisely controlling the resistance value based on a digital signal. A digital potentiometer consists of a voltage divider and a controller. The voltage divider consists of a series of resistors that divide the input voltage according to a specific ratio. Each resistor is connected to an input pin of the controller. The controller reads the control signal and opens or closes the corresponding switch based on the signal level, thereby changing the corresponding resistor value. This allows the digital signal to be output through program control to change the resistance value, thus completing the voltage regulation function for an input waveform signal with a fixed amplitude.

[0031] An AC coupler is connected to the output of the digital potentiometer. The signal output by the AC coupler's output circuit is superimposed with the signal output by the DAC circuit and then injected into the VCO voltage-controlled oscillator. This creates a programmable sweep signal source with controllable bandwidth, sweep frequency, and center frequency. The AC coupler circuit blocks the DC component of the digital potentiometer's output and transmits the AC component. This ensures the linearity of the coupled output sawtooth signal within a unit cycle, thereby ensuring the consistency of the frequency change rate within the sweep cycle.

[0032] A VCO (voltage-controlled oscillator) is an oscillator controlled by an input voltage (tuning voltage). Adjusting the tuning voltage proportionally changes the frequency of the output RF signal. Its performance indicators include frequency tuning range, tuning sensitivity, output power, frequency stability, and phase noise.

[0033] The power supply circuit uses an AD-DC switching circuit, a DC-DC power converter or a linear voltage regulation circuit to provide a stable power supply for the entire system.

[0034] In view of the inconvenience of adjusting the bandwidth, sweep frequency and center frequency of the current sweep signal source, a programmable sweep signal source circuit is proposed, which realizes flexible adjustment of the sweep signal through digital control. Its working process is as follows:

[0035] The MCU calculates the sawtooth wave signal period and the corresponding frequency control value based on the input control signal and the sweep frequency, and inputs the value into the sawtooth wave signal generator circuit to generate a sawtooth wave signal with a fixed amplitude;

[0036] The MCU converts the sweep signal source bandwidth into the corresponding sawtooth wave AC amplitude according to the VCO tuning sensitivity, and then calculates the signal voltage divider adjustment coefficient based on the specific amplitude of the sawtooth wave signal generator. The coefficient is converted into the control word of the digital potentiometer and input into the digital potentiometer.

[0037] The MCU calculates the corresponding bias voltage based on the bandwidth of the sweep signal source according to the VCO's frequency tuning range, tuning sensitivity and other related performance parameters, obtains the corresponding voltage digital signal, transmits it to the DAC circuit, and converts it into an analog voltage signal;

[0038] After the analog voltage signal is superimposed on the sawtooth AC signal, it is injected into the VCO tuning control terminal to obtain a programmable sweep signal source with controllable bandwidth, sweep frequency and center frequency.

[0039] Flexible adjustment of the sweep signal is achieved through digital control, which solves the inconvenience of adjusting the bandwidth, sweep frequency and center frequency of the sweep signal source. At the same time, the diversity of the power supply circuit also ensures the stability and reliability of the system.

[0040] Example 2

[0041] like Figure 2 As shown, another embodiment of the present invention is a controllable signal generator using direct digital synthesis (DDS) technology. Based on a highly stable reference clock as a reference source, the sawtooth wave generator generates the desired digital waveform through a phase accumulator, digital signal processing, and a high-speed D / A converter. After passing through a low-pass filter, the final sawtooth signal waveform is obtained. Furthermore, the sawtooth wave period of the sawtooth wave generator can be set using a frequency control word, while the signal amplitude is fixed.

[0042] To address the fixed amplitude of the sawtooth wave signal generated by the aforementioned circuit, a digital potentiometer is connected to the output of the sawtooth generator, replacing the traditional mechanical potentiometer. By program-controlled output of a digital signal, the digital potentiometer's resistance value is changed, achieving voltage regulation for the fixed-amplitude input waveform signal.

[0043] This embodiment realizes the controllability of the bandwidth, sweep frequency and center frequency of the sweep signal source through the coordinated operation of the sawtooth wave generator and the digital potentiometer.

[0044] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A program-controlled frequency sweep signal source circuit, characterized in that: Including sawtooth wave generator, digital potentiometer, MCU control circuit and DAC circuit; The output end of the MCU control circuit is connected to the input ends of the sawtooth wave generator, the digital potentiometer and the DAC circuit respectively, and the input end of the MCU control circuit is used to receive the control signal; The sawtooth wave generator input end is connected to the MCU control circuit, the sawtooth wave generator output end is connected to the digital potentiometer, and the sawtooth wave generator is used to generate a sawtooth waveform signal; The digital potentiometer input end is connected to the sawtooth wave generator and the MCU control circuit respectively, and the digital potentiometer is used to perform voltage regulation control on the amplitude of the waveform signal generated by the sawtooth wave generator; The DAC circuit input end is connected to the MCU control circuit output end, and the MCU control circuit sends a control signal to the DAC circuit. The DAC circuit is used to convert the voltage digital signal into an analog voltage signal.

2. A program-controlled frequency sweep signal source circuit according to claim 1, characterized in that: The circuit also includes an AC coupler circuit, a VCO voltage-controlled oscillator and a power supply circuit; The AC coupler circuit input end is connected to the digital potentiometer, and the AC coupler circuit output end is connected to the VCO voltage-controlled oscillator input end. The AC coupler circuit is used to block the DC component output by the digital potentiometer; The VCO voltage-controlled oscillator input end is connected to the AC coupler circuit and the DAC circuit, and the VCO voltage-controlled oscillator is used to output a programmable frequency sweep signal source; The output end of the power supply circuit is connected to the digital potentiometer, and the power supply circuit is used to provide power for the circuit.

3. The program-controlled frequency sweep signal source circuit according to claim 1, characterized in that: The sawtooth wave generator is a controllable signal generator using direct digital frequency synthesis technology.

4. The program-controlled frequency sweep signal source circuit according to claim 1, characterized in that: The digital potentiometer includes a voltage divider and a controller. The voltage divider includes multiple groups of resistor elements, and the resistor elements are connected to the input pins of the controller; the controller is used to read the control signal to change the resistance size in the voltage divider.

5. The program-controlled frequency sweep signal source circuit according to claim 1, characterized in that: The input signal at the input end of the DAC circuit is a voltage digital signal, and the output signal at the output end of the DAC circuit is an analog voltage signal.

6. The program-controlled frequency sweep signal source circuit according to claim 2, characterized in that: The output end of the AC coupler circuit is connected to the DAC circuit, and the analog voltage signal output by the DAC circuit and the sawtooth wave signal output by the AC coupler circuit are superimposed to form a VCO tuning voltage signal.

7. The program-controlled frequency sweep signal source circuit according to claim 6, characterized in that: The VCO voltage-controlled oscillator input end is used to be connected to the VCO tuning voltage signal, and the VCO voltage-controlled oscillator output end is used to output a program-controlled frequency sweeping signal source.

8. The program-controlled frequency sweep signal source circuit according to claim 1, characterized in that: The power supply circuit is an AD-DC switching circuit or a DC-DC power converter.

9. The program-controlled frequency sweep signal source circuit according to claim 7, characterized in that: The VCO voltage-controlled oscillator is used to adjust the tuning voltage within an adjustable range.

10. The program-controlled frequency sweep signal source circuit according to claim 1, characterized in that: The control signals received by the input end of the MCU control circuit are the sweep frequency, the sweep bandwidth and the center frequency point.

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