High-precision vector regulation and control device and method for signal generation link

Abstract

The invention discloses a high-precision vector regulation and control device and method for a signal generation link, and belongs to the technical field of information. A frequency mixing feedback loop is adopted to replace a traditional ALC detection loop, the amplitude of a signal can be stabilized, the phase of the signal can also be stabilized, and impedance matching of a channel can also be regulated and controlled; a path feedback signal is converted into a digital signal for high-speed transmission, and the ADC, the signal processing module and the DDS are interconnected through a high-speed bus, so that high-speed vector regulation and control can be quickly performed, and the loop control speed is higher; according to the invention, the direct digital frequency synthesizer is in a loop, which means that the amplitude and phase drift in the DDS can also be captured by the loop for correction; according to the method, vector information of the amplitude and phase drift of the channel can be obtained at the same time, so that closed-loop dual control, namely vector control, is carried out, and the purpose of regulating and controlling the amplitude and phase of the signal at the same time is achieved.

Description

Technical Field

[0001] The present invention belongs to the field of information technology, and in particular relates to a high-precision vector control device and method for a signal generation link. Background Art

[0002] Direct digital frequency synthesizers (DDSs) have the advantages of high integration, high frequency, and phase accuracy, and are widely used in instrumentation, broadband and high-speed satellite communications, electromagnetic spectrum signal monitoring, electronic countermeasures, and intersatellite communication simulation testing. However, DDSs are rarely used directly as the final signal output in high-end instruments. Signal conditioning is usually performed instead. However, current signal conditioning can only control one variable, amplitude, meaning it can only stabilize amplitude. Amplitude stabilization is usually achieved through an automatic level control (ALC) loop consisting of a conditioning channel, coupling, detection, logarithmic amplification, summing op amp, and amplitude stabilization control.

[0003] Automatic Level Control (ALC) maintains a constant output level when the input level varies within a wide range. Specifically, when the input signal power is unstable or fluctuates significantly, the output signal power remains stable at a relatively constant amplitude after the ALC loop stabilizes the amplitude. To ensure stable output power, an ALC loop is necessary in RF amplifier circuits. Figure 1 The signal conditioning channel is composed of an electrically adjustable attenuator, an amplifier, a digitally controlled attenuator, an amplitude stabilization controller, etc.

[0004] After the output signal of the direct digital frequency synthesizer is amplified by the RF amplifier circuit, the directional coupler couples out part of the power in proportion, and generates a detection voltage after passing through the detector. The detection voltage is logarithmically amplified, and the logarithmic voltage value is summed and integrated with the preset reference voltage. The output voltage of the summing circuit is fed back to the electrically adjustable attenuator in the control signal conditioning channel to form a negative feedback loop, so that the RF signal power is output constantly.

[0005] With the development of high-end equipment such as phased array radar, communications, and satellite communications, the demand for phase stability is increasing. Furthermore, signal generators are required to be able to adjust channel impedance to match test loads or offset impedance mismatches in test cables and fixtures. Therefore, the direct digital frequency synthesizer (DDS) in the signal generator must be able to perform vector adjustment, simultaneously controlling both amplitude and phase information.

[0006] The existing technology has three shortcomings. First, the existing ALC technology can only control one variable, the amplitude, that is, it can only stabilize the amplitude and maintain stable power output, and cannot obtain and control the phase information of the signal. The present invention can simultaneously obtain vector information of amplitude and phase, and can also simultaneously perform vector control on the amplitude and phase of the DDS. At the same time, it can control the impedance of the signal conditioning path by obtaining the amplitude and phase information of the reflected signal, and thus match the impedance of the test load. Second, the entire loop is composed entirely of analog circuits, the circuit system is cumbersome and complex, and the control speed is slow. The signal processing of the present invention is completed by a high-speed FPGA, and the amplitude and phase control is directly completed by the FPGA controlling the DDS, which is faster. Third, the amplitude and phase drift formed by the direct digital frequency synthesizer itself outside the control loop cannot be detected by the loop, so it cannot form a closed loop in real time. Summary of the Invention

[0007] In response to the above technical problems existing in the prior art, the present invention proposes a high-precision vector control device and method for a signal generation link, which has a reasonable design, overcomes the shortcomings of the prior art, and has good effects.

[0008] In order to achieve the above object, the present invention adopts the following technical solutions:

[0009] A high-precision vector control device for a signal generation link includes a signal processing module, a direct digital frequency synthesizer, a signal conditioning channel, a coupler, an amplifier, a mixer, an intermediate frequency conditioning module, an analog-to-digital converter, a local oscillator module, and a reference distribution module. The signal processing module, the direct digital frequency synthesizer, the signal conditioning channel, the coupler, the amplifier, the mixer, the intermediate frequency conditioning module, and the analog-to-digital converter form a closed mixing feedback loop for simultaneously controlling the amplitude and phase of a signal. The reference distribution module is connected to the local oscillator module and the direct digital frequency synthesizer via lines, and the local oscillator module is connected to the mixer via lines.

[0010] a signal processing module configured to generate waveform data and generate a control signal according to a feedback signal;

[0011] a direct digital frequency synthesizer configured to receive waveform data, perform vector control according to a control signal, and generate a radio frequency signal;

[0012] A signal conditioning channel is configured to perform signal conditioning on a radio frequency signal;

[0013] a coupler configured to couple a portion of the output signal;

[0014] an amplifier configured to amplify the coupled signal;

[0015] A reference distribution module is configured to distribute a high-precision reference signal to both the local oscillator module and the direct digital frequency synthesizer to ensure phase synchronization between the local oscillator signal and the radio frequency signal;

[0016] A local oscillator module is configured to generate a local oscillator signal;

[0017] a mixer configured to mix the amplified coupled signal with a local oscillator signal to generate an intermediate frequency signal;

[0018] An intermediate frequency conditioning module, configured to condition the intermediate frequency signal;

[0019] The analog-to-digital converter is configured to convert the intermediate frequency signal into a digital signal and send the digital signal to the signal processing module.

[0020] Preferably, the signal processing module is configured to analyze the digital signal output by the ADC, and correct the amplitude and phase drift of the direct digital frequency synthesizer based on the digital signal.

[0021] Preferably, the mixer feedback loop is configured to stabilize the amplitude of the signal, stabilize the phase of the signal, and achieve impedance matching of the signal conditioning channel.

[0022] Preferably, the impedance matching is achieved by adjusting an output signal of a direct digital frequency synthesizer.

[0023] Preferably, the local oscillator module is co-referenced with the direct digital frequency synthesizer to maintain synchronization.

[0024] In addition, the present invention also provides a high-precision vector control method for a signal generation link, which uses the high-precision vector control device for a signal generation link as described above, and includes the following steps:

[0025] Step 1: Generate waveform data through the signal processing module and send it to the direct digital frequency synthesizer;

[0026] Step 2: The direct digital frequency synthesizer generates an RF signal based on the received waveform data and outputs it to the signal conditioning channel;

[0027] Step 3: Condition the RF signal through the signal conditioning channel and send it to the coupler;

[0028] Step 4: Extract part of the output signal through the coupler and send it to the amplifier;

[0029] Step 5: Amplify the extracted output signal through the amplifier and send the amplified signal to the mixer;

[0030] Step 6: Generate a local oscillator signal through the local oscillator module and send it to the mixer;

[0031] Step 7: Mix the amplified coupled signal with the local oscillator signal through a mixer to generate an intermediate frequency signal;

[0032] Step 8: Condition the intermediate frequency signal through the intermediate frequency conditioning module and then output it to the analog-to-digital converter;

[0033] Step 9: Convert the intermediate frequency signal into a digital signal through an analog-to-digital converter and send it to the signal processing module;

[0034] Step 10: The signal processing module performs vector analysis on the digital signal, extracts amplitude and phase information, generates a corresponding control signal, and sends the control signal to the direct digital frequency synthesizer to adjust the output signal of the direct digital frequency synthesizer to achieve vector control.

[0035] The beneficial technical effects brought about by the present invention are:

[0036] 1. Existing technologies can only control one variable, amplitude. This means they can only stabilize amplitude and maintain stable power output, but cannot obtain and control the signal's phase information. The present invention uses a mixer feedback loop to replace the traditional ALC detection loop, stabilizing both the signal amplitude and phase, and also controlling the channel's impedance matching.

[0037] 2. In the prior art, the entire loop is composed of analog circuits, the circuit system is cumbersome and complex, and the control speed is slow. The present invention converts the path feedback signal into a digital signal for high-speed transmission. The ADC, signal processing module and DDS are all interconnected by a high-speed bus, which can quickly perform high-speed vector control and faster loop control speed.

[0038] 3. The direct digital frequency synthesizer in the prior art is outside the control loop, and the amplitude and phase drifts generated by itself cannot be detected by the loop. The direct digital frequency synthesizer of the present invention is inside the loop, which means that the amplitude and phase drifts inside the DDS will also be captured by the loop and then corrected, which other loop structures cannot do. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a schematic diagram of the traditional ALC loop;

[0040] Figure 2 Schematic diagram of the vector control loop of the present invention. DETAILED DESCRIPTION

[0041] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0042] The technical solution of the present invention is as follows Figure 2 shown.

[0043] The waveform data for a direct digital synthesizer is generated by a signal processing module, typically comprised of a high-speed FPGA or DSP. A direct digital synthesizer can consist of a DDS or high-performance DAC with a high-speed interface. This receives real-time waveform data from the signal processing module and generates the RF signal.

[0044] The signal conditioning channel usually includes an electrically adjustable attenuator, an amplifier, a digitally controlled attenuator, an amplitude stabilizer controller, etc., which are used to condition the signal. The signal conditioning electrically adjustable attenuator in the present invention may not be a continuous analog voltage-controlled attenuator. The linearity of an external continuous analog voltage-controlled attenuator is limited, which will deteriorate the signal quality. Therefore, the present invention can perform high-precision amplitude control in a direct digital frequency synthesizer, avoiding signal deterioration.

[0045] The coupler can be a traditional unidirectional coupler or a bidirectional coupler. The unidirectional coupler only extracts and analyzes the amplitude and phase information of the output signal, while the bidirectional coupler can be used to extract and analyze the amplitude and phase of the reflected signal at the same time. The signal after coupling is generally small, and an amplifier is required to amplify the feedback signal. The local oscillator signal mixes the feedback amplified signal into an intermediate frequency signal of several hundred MHz.

[0046] The local oscillator and direct digital frequency synthesizer of the present invention must be used for reference. Generally, the higher the reference signal, the better, to ensure that the RF signal and the mixed local oscillator signal remain synchronized. Only with synchronization can the phase information of the RF signal be accurately obtained. After mixing, signal conditioning is still required, including signal amplification and attenuation, etc., to adjust the feedback signal to an amplitude range suitable for ADC sampling. The ADC uses a high-precision ADC with a relatively high bit number, such as 12, 14, or 16 bits, and the feedback intermediate frequency signal is converted into a digital signal.

[0047] The signal processing module is generally an FPGA, DSP or high-speed ARM chip, which is interconnected with the ADC with a high-speed data line to ensure high-speed signal transmission. The signal processing module performs vector analysis on the collected feedback signal, which is generally I and Q signals, and extracts the amplitude and phase information of the feedback signal at the same time. It also generates a control signal from the feedback information through an algorithm, which is generally controlled as I and Q signals. The I, Q control signals are vector-modulated with the original waveform data and sent to the direct digital frequency synthesizer through a high-speed data bus to generate a vector-controlled RF signal. The entire feedback loop is very fast, completing high-speed feedback control over and over again, and correcting the amplitude and phase drift of the channel at high speed to ensure the stability of the amplitude and phase of the output signal. At the same time, since the output signal is a vector-modulated signal, the impedance of the entire path can also be changed to match the impedance of the output test load.

[0048] The key points and protection points of the present invention are:

[0049] 1. The loop architecture of the present invention is relatively innovative. It structurally introduces a local oscillator and mixing feedback loop, in which the local oscillator and DDS are highly synchronized through a high-frequency reference, replacing the traditional ALC detection loop. It can stabilize the signal amplitude and phase, and can also adjust the impedance matching of the channel. In this way, regardless of the load impedance changes, impedance matching can be achieved by changing the DDS data waveform in real time, which is very convenient for users.

[0050] 2. The feedback signal of the path is converted into a digital signal for high-speed transmission. The ADC, signal processing module and DDS are all interconnected by a high-speed bus, which can quickly perform high-speed vector control, making the loop control faster and more stable.

[0051] 3. The direct digital frequency synthesizer is within the loop, which means that the amplitude and phase drift within the DDS will also be captured by the loop and then corrected, which other loop structures cannot do. Therefore, the accuracy and preparation are higher.

[0052] Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by technicians in this technical field within the essential scope of the present invention should also fall within the scope of protection of the present invention.

Claims

1. A high-precision vector control device for a signal generation link, characterized in that: The system comprises a signal processing module, a direct digital frequency synthesizer, a signal conditioning channel, a coupler, an amplifier, a mixer, an intermediate frequency conditioning module, an analog-to-digital converter, a local oscillator module, and a reference distribution module; wherein the signal processing module, the direct digital frequency synthesizer, the signal conditioning channel, the coupler, the amplifier, the mixer, the intermediate frequency conditioning module, and the analog-to-digital converter form a closed mixing feedback loop for simultaneously controlling the amplitude and phase of the signal; the reference distribution module is respectively connected to the local oscillator module and the direct digital frequency synthesizer through lines, and the local oscillator module is connected to the mixer through lines; a signal processing module configured to generate waveform data and generate a control signal according to a feedback signal; a direct digital frequency synthesizer configured to receive waveform data, perform vector control according to a control signal, and generate a radio frequency signal; A signal conditioning channel is configured to perform signal conditioning on a radio frequency signal; a coupler configured to couple a portion of the output signal; an amplifier configured to amplify the coupled signal; A reference distribution module is configured to distribute a high-precision reference signal to both the local oscillator module and the direct digital frequency synthesizer to ensure phase synchronization between the local oscillator signal and the radio frequency signal; A local oscillator module is configured to generate a local oscillator signal; a mixer configured to mix the amplified coupled signal with a local oscillator signal to generate an intermediate frequency signal; An intermediate frequency conditioning module, configured to condition the intermediate frequency signal; The analog-to-digital converter is configured to convert the intermediate frequency signal into a digital signal and send the digital signal to the signal processing module.

2. The high-precision vector control device for a signal generation link according to claim 1, characterized in that: The signal processing module is configured to analyze the digital signal output by the ADC and correct the amplitude and phase drift of the direct digital frequency synthesizer based on the digital signal.

3. The high-precision vector control device for a signal generation link according to claim 1, characterized in that: The mixing feedback loop is configured to stabilize the amplitude and phase of the signal and achieve impedance matching of the signal conditioning channel.

4. The high-precision vector control device for a signal generation link according to claim 3, characterized in that: Impedance matching is achieved by adjusting the output signal of the direct digital frequency synthesizer.

5. The high-precision vector control device for a signal generation link according to claim 1, characterized in that: The local oscillator module is referenced to the direct digital frequency synthesizer to maintain synchronization.

6. A high-precision vector control method for a signal generation link, characterized in that: The high-precision vector control device for a signal generation link according to claim 1 comprises the following steps: Step 1: Generate waveform data through the signal processing module and send it to the direct digital frequency synthesizer; Step 2: The direct digital frequency synthesizer generates an RF signal based on the received waveform data and outputs it to the signal conditioning channel; Step 3: The RF signal is conditioned through the signal conditioning channel and sent to the coupler; Step 4: Extract part of the output signal through the coupler and send it to the amplifier; Step 5: Amplify the extracted output signal through the amplifier and send the amplified signal to the mixer; Step 6: Generate a local oscillator signal through the local oscillator module and send it to the mixer; Step 7: Mix the amplified coupled signal with the local oscillator signal through a mixer to generate an intermediate frequency signal; Step 8: Condition the intermediate frequency signal through the intermediate frequency conditioning module and then output it to the analog-to-digital converter; Step 9: Convert the intermediate frequency signal into a digital signal through an analog-to-digital converter and send it to the signal processing module; Step 10: The signal processing module performs vector analysis on the digital signal, extracts amplitude and phase information, generates a corresponding control signal, and sends the control signal to the direct digital frequency synthesizer to adjust the output signal of the direct digital frequency synthesizer to achieve vector control.

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