A signal generation system and method

Abstract

The application relates to the technical field of signal generation, and discloses a signal generation system and method, which comprises a first signal generation module, a second signal generation module comprising an analog signal generation unit and a signal replication unit, and a signal mixing module comprising an analog mixing unit, a digital mixing unit and a signal switching unit; the output end of the analog signal generation unit is connected with the input end of the analog mixing unit; the first end of the signal replication unit is connected with the clock signal output end of the analog signal generation unit, the second end is connected with the mixing input end of the analog signal generation unit, and the third end is connected with the first end of the signal switching unit; the second end of the signal switching unit is connected with the output end of the analog mixing unit, and the third end is connected with the input end of the digital mixing unit. Thus, the direct digital frequency synthesizer in the analog signal generation unit is calibrated when switching to a clock signal, and a spur signal is eliminated based on the calibration result when switching to an analog local oscillator signal.

Description

Technical Field

[0001] This invention relates to the field of signal generation technology, and more specifically to a signal generation system and method. Background Technology

[0002] High-performance spectrum analyzers generally use methods based on direct digital frequency synthesizers (DDS) and mixing phase-locked loops to generate analog local oscillator signals. However, due to the inherent characteristics of digital sampling, the output signal of a direct digital frequency synthesizer has inherent spurious components. These spurious components will be transmitted to the analog local oscillator signal and will eventually appear in the spectrum analysis results, degrading the spurious-free dynamic range of the instrument. Summary of the Invention

[0003] This invention provides a signal generation system and method to solve the problem of local oscillator spurious emissions introduced by direct digital frequency synthesizers.

[0004] In a first aspect, the present invention provides a signal generation system, the system comprising:

[0005] The first signal generation module is used to generate digital local oscillator signals;

[0006] The second signal generation module includes: an analog signal generation unit and a signal replication unit;

[0007] And, a signal mixing module, including: an analog mixing unit, a digital mixing unit, and a signal switching unit;

[0008] The output of the analog signal generation unit is connected to the input of the analog mixer unit.

[0009] The first end of the signal copying unit is connected to the clock signal output of the analog signal generation unit, the second end is connected to the mixer input of the analog signal generation unit, and the third end is connected to the first end of the signal switching unit. The signal copying unit is used to copy the clock signal generated in the analog signal generation unit to the signal switching unit.

[0010] The second terminal of the signal switching unit is connected to the output terminal of the analog mixer unit, and the third terminal is connected to the input terminal of the digital mixer unit.

[0011] In one alternative implementation, the analog signal generation unit includes a direct digital frequency synthesizer, a local oscillator generator, and a mixer phase-locked loop;

[0012] The input terminals of the direct digital frequency synthesizer and the local oscillator are respectively connected to reference signals. The direct digital frequency synthesizer is used to generate clock signals based on the reference signals, and the local oscillator is used to generate point frequency signals based on the reference signals.

[0013] The output of the direct digital frequency synthesizer is connected to the first end of the signal replication unit;

[0014] The first input terminal of the mixing phase-locked loop is connected to the second terminal of the signal replication unit, the second input terminal is connected to the output terminal of the local oscillator generator, and the output terminal is connected to the analog mixing unit.

[0015] In one alternative implementation, the signal replication unit is a coupler, a power divider, or a switch.

[0016] In one optional implementation, the analog mixing unit includes an analog mixer, with a first input terminal of the analog mixer receiving a high-frequency signal, a second input terminal connected to the output terminal of the analog signal generation unit, and the output terminal connected to the second terminal of the signal switching unit.

[0017] In one alternative implementation, the digital mixing unit includes an analog-to-digital converter and a digital mixer;

[0018] The input terminal of the analog-to-digital converter is connected to the third terminal of the signal switching unit, and the output terminal is connected to the first input terminal of the digital mixer.

[0019] The second input terminal of the digital mixer is connected to the output terminal of the first signal generation module, and the output terminal outputs the baseband signal.

[0020] In one alternative implementation, the first signal generation module includes a numerically controlled oscillator;

[0021] The input of the numerically controlled oscillator is connected to a reference signal, and the output is connected to a digital mixer unit. The numerically controlled oscillator is used to generate a digital local oscillator signal based on the reference signal.

[0022] In one optional implementation, the system further includes: a reference signal generation module, which includes a crystal oscillator, a frequency multiplier, and a power divider;

[0023] The crystal oscillator is connected to the input of the frequency multiplier, and the output of the frequency multiplier is connected to the input of the power divider.

[0024] The output of the power divider is connected to the direct digital frequency synthesizer, the local oscillator generator, and the first signal generation module of the analog mixer unit, respectively.

[0025] The signal generation system provided in this embodiment of the invention includes a signal copying unit in the second signal generation module and a signal switching unit in the signal mixing module. The signal copying unit copies the clock signal generated in the second signal generation module to the signal switching unit. The signal switching unit can select and output the clock signal and the analog local oscillator signal in the second signal generation module. Thus, when switching to the clock signal, the direct digital frequency synthesizer in the analog signal generation unit can be calibrated. When switching to the analog local oscillator signal, the spurious signals introduced into the local oscillator signal are eliminated based on the calibration results of the direct digital frequency synthesizer.

[0026] In a second aspect, the present invention provides a signal generation method, applied to a signal generation system of the first aspect or any corresponding embodiment thereof, the method comprising:

[0027] The reference clock signal frequency is determined based on the preset intermediate frequency signal frequency and the input high frequency signal frequency.

[0028] Based on the preset correspondence between clock signal frequency and signal power ratio, the reference clock signal frequency is searched to determine the corresponding signal power ratio. The correspondence between clock signal frequency and signal power ratio is obtained by calibrating the signal generation system.

[0029] If the signal power ratio is not within the preset range, within the preset offset frequency range, determine the target offset frequency so that the signal power ratio after the target offset frequency correction is within the preset range;

[0030] The analog local oscillator signal and the digital local oscillator signal are corrected based on the target offset frequency.

[0031] In one optional implementation, determining the target offset frequency within a preset offset frequency range includes:

[0032] Based on a preset offset frequency range, the first offset frequency and the second offset frequency are determined.

[0033] Based on the first offset frequency and the second offset frequency, the reference clock signal is corrected and searched respectively to obtain the first power ratio corresponding to the first offset frequency and the second power ratio corresponding to the second offset frequency.

[0034] The offset frequency range is updated based on the first power ratio corresponding to the first offset frequency and the second power ratio corresponding to the second offset frequency.

[0035] Repeat the following steps: Based on the updated offset frequency range, update the first offset frequency and the second offset frequency. Based on the updated first offset frequency and the second offset frequency, correct and search the reference clock signal respectively, update the first power ratio corresponding to the first offset frequency and the second power ratio corresponding to the second offset frequency to update the offset frequency range, until the interval length corresponding to the offset frequency range is less than the preset threshold, and determine the middle frequency value of the offset frequency range as the target offset frequency.

[0036] In one optional implementation, the analog local oscillator signal and the digital local oscillator signal are corrected based on the target offset frequency, including:

[0037] The simulated local oscillator signal is added to the signal at the target offset frequency to obtain the corrected simulated local oscillator signal;

[0038] The corrected digital local oscillator signal is obtained by subtracting the signal at the target offset frequency from the digital local oscillator signal.

[0039] The signal generation method provided in this embodiment of the invention calibrates the signal generation system to obtain the correspondence between the clock signal frequency and the signal power ratio. Based on the correspondence between the clock signal frequency and the signal power ratio, the signal power ratio corresponding to the reference clock signal frequency is determined. Based on the signal power ratio, the target offset frequency is determined within a preset offset frequency range. Thus, the analog local oscillator signal and the digital local oscillator signal are corrected based on the target offset frequency to eliminate spurious signals introduced into the local oscillator signal. Attached Figure Description

[0040] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0041] Figure 1 This is a schematic diagram of the structure of a signal generation system according to an embodiment of the present invention;

[0042] Figure 2 This is a schematic diagram of the architecture of a signal generation system according to an embodiment of the present invention;

[0043] Figure 3 This is a flowchart of a signal generation method according to an embodiment of the present invention;

[0044] Explanation of reference numerals in the attached figures:

[0045] 1. First signal generation module; 2. Second signal generation module; 21. Analog signal generation unit; 22. Signal replication unit; 3. Signal mixing module; 31. Analog mixing unit; 32. Digital mixing unit; 33. Signal switching unit; 4. Reference signal generation module. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0047] It is understood that before using the technical solutions disclosed in the various embodiments of the present invention, users should be informed of the types, scope of use, and usage scenarios of the personal information involved in the present invention and their authorization should be obtained in accordance with relevant laws and regulations through appropriate means.

[0048] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0049] High-performance spectrum analyzers generally use methods based on direct digital frequency synthesizers (DDS) and mixing phase-locked loops to generate analog local oscillator signals. However, due to the inherent characteristics of digital sampling, the output signal of a direct digital frequency synthesizer has inherent spurious components. These spurious components will be transmitted to the analog local oscillator signal and will eventually appear in the spectrum analysis results, degrading the spurious-free dynamic range of the instrument.

[0050] In related technologies, spurious emissions are mainly suppressed at the source by improving the phase accumulator or waveform mapping algorithm inside the direct digital frequency synthesizer. However, this method is costly and cannot completely eliminate all spurious emissions, especially near-end spurious emissions. Another related technology involves recording and calibrating the spurious characteristics of the direct digital frequency synthesizer to avoid introducing spurious emissions by avoiding known severe spurious frequencies during operation. However, this method is static and passive, unable to adapt to spurious changes caused by temperature and device aging, and lacks flexibility.

[0051] To address the aforementioned technical problems, embodiments of the present invention provide a signal generation system, comprising: a first signal generation module for generating a digital local oscillator signal; a second signal generation module including an analog signal generation unit and a signal replication unit; and a signal mixing module including an analog mixing unit, a digital mixing unit, and a signal switching unit; wherein the output terminal of the analog signal generation unit is connected to the input terminal of the analog mixing unit; a first terminal of the signal replication unit is connected to the clock signal output terminal of the analog signal generation unit, a second terminal is connected to the mixing input terminal of the analog signal generation unit, and a third terminal is connected to the first terminal of the signal switching unit, the signal replication unit being used to replicate the clock signal generated in the analog signal generation unit to the signal switching unit; a second terminal of the signal switching unit is connected to the output terminal of the analog mixing unit, and a third terminal is connected to the input terminal of the digital mixing unit. A signal copying unit is set in the second signal generation module, and a signal switching unit is set in the signal mixing module. The clock signal generated in the second signal generation module is copied to the signal switching unit through the signal copying unit. The signal switching unit can select the output of the clock signal and the analog local oscillator signal in the second signal generation module. Thus, when switching to the clock signal, the direct digital frequency synthesizer in the analog signal generation unit can be calibrated. When switching to the analog local oscillator signal, the spurious signals introduced into the local oscillator signal are eliminated based on the calibration results of the direct digital frequency synthesizer.

[0052] According to an embodiment of the present invention, a signal generation system embodiment is provided. Figure 1 This is a schematic diagram of the structure of a signal generation system according to an embodiment of the present invention, such as... Figure 1 As shown, the system includes: a first signal generation module, a second signal generation module, and a signal mixing module. The signal mixing module is connected to both the first and second signal generation modules. The first signal generation module generates a digital local oscillator signal, the second signal generation module generates an analog local oscillator signal, and the signal mixing module mixes the digital and analog local oscillator signals to output a baseband signal.

[0053] In this embodiment of the invention, the second signal generation module includes an analog signal generation unit and a signal copying unit. The analog signal generation unit is used to generate an analog local oscillator signal and is equipped with a direct digital frequency synthesizer. The signal copying unit is used to copy the clock signal generated in the analog signal generation unit to the signal switching unit in the signal mixing module, that is, to copy the clock signal generated by the direct digital frequency synthesizer to the signal switching unit.

[0054] In this embodiment of the invention, the signal mixing module includes: an analog mixing unit, a digital mixing unit, and a signal switching unit. The analog mixing unit is used to mix the input high-frequency signal with the analog local oscillator signal generated by the analog signal generation unit to obtain an intermediate frequency signal. The digital mixing unit is used to mix the intermediate frequency signal with the digital local oscillator signal to obtain and output a baseband signal.

[0055] In this embodiment of the invention, the output terminal of the analog signal generation unit is connected to the input terminal of the analog mixing unit; the first terminal of the signal replication unit is connected to the clock signal output terminal of the analog signal generation unit, the second terminal is connected to the mixing input terminal of the analog signal generation unit, and the third terminal is connected to the first terminal of the signal switching unit; the second terminal of the signal switching unit is connected to the output terminal of the analog mixing unit, and the third terminal is connected to the input terminal of the digital mixing unit.

[0056] In one alternative implementation, Figure 2 This is a schematic diagram of the architecture of a signal generation system according to an embodiment of the present invention, such as... Figure 2 As shown, the analog signal generation unit includes a direct digital frequency synthesizer, a local oscillator generator, and a mixer phase-locked loop.

[0057] In this system, the inputs of the direct digital frequency synthesizer (DDS) and the local oscillator (LOO) are respectively connected to reference signals. The DDS generates a clock signal based on the reference signals, and the LOO generates point frequency signals based on the reference signals. Specifically, the DDS converts the reference signals into a low-frequency variable clock through digital control, and the LOO generates multiple point frequency sources, such as 3.5GHz, 4GHz, 5GHz, 6GHz, etc., after frequency multiplication and filtering of the reference signals.

[0058] The output of the direct digital frequency synthesizer is connected to the first terminal of the signal replication unit. The first input of the mixing phase-locked loop is connected to the second terminal of the signal replication unit, the second input is connected to the output of the local oscillator generator, and the output is connected to the analog mixing unit. The mixing phase-locked loop mixes and locks the clock signal output by the direct digital frequency synthesizer and the point frequency signal output by the local oscillator generator to output an analog local oscillator signal. The frequency of the analog local oscillator signal is equal to the sum of the frequencies of the clock signal output by the direct digital frequency synthesizer and the point frequency signal output by the local oscillator generator.

[0059] In one alternative implementation, the signal replication unit is a coupler, a power divider, or a switch.

[0060] In one alternative implementation, such as Figure 2As shown, the analog mixing unit includes an analog mixer. The first input terminal of the analog mixer receives a high-frequency signal, the second input terminal is connected to the output terminal of the analog signal generation unit, and the output terminal is connected to the second terminal of the signal switching unit. The analog mixer mixes the input high-frequency signal and the analog local oscillator signal, down-converting them to an intermediate frequency (IF) signal. The frequency range of the input high-frequency signal is 2-57 GHz, and the frequency of the resulting IF signal is equal to the difference between the frequency of the high-frequency signal and the frequency of the analog local oscillator signal.

[0061] In one alternative implementation, such as Figure 2 As shown, the digital mixing unit includes an analog-to-digital converter (ADC) and a digital mixer. The ADC's input is connected to the third terminal of the signal switching unit, and its output is connected to the first input of the digital mixer. The digital mixer's second input is connected to the output of the first signal generation module, and its output is a baseband signal. The ADC converts the analog intermediate frequency (IF) signal into a digital IF signal, which is then input to the digital mixer for mixing. The digital mixer mixes the converted analog local oscillator (LoU) signal and the digital LoU signal, outputting a baseband signal. The frequency of the resulting baseband signal is equal to the difference between the frequency of the digital IF signal and the frequency of the digital LoU signal.

[0062] In one alternative implementation, the signal switching unit is used to select between the intermediate frequency signal output by the analog mixer and the clock signal output by the direct digital frequency synthesizer. When selecting the output clock signal, i.e., the direct digital frequency synthesizer link, the direct digital frequency synthesizer is calibrated. When selecting the output intermediate frequency signal, i.e., the analog local oscillator signal, the signal processing link, spurious signals introduced into the local oscillator are eliminated based on the calibration results of the direct digital frequency synthesizer.

[0063] In one alternative implementation, such as Figure 2 As shown, the first signal generation module includes a numerically controlled oscillator. The input of the numerically controlled oscillator is connected to a reference signal, and its output is connected to a digital mixer unit. The numerically controlled oscillator is used to generate a digital local oscillator signal based on the reference signal.

[0064] In one optional implementation, the reference signal accessed by the first signal generation module and the second signal generation module is the same. Accordingly, the signal generation system further includes a reference signal generation module, which comprises a crystal oscillator, a frequency multiplier, and a power divider. The crystal oscillator is connected to the input of the frequency multiplier, the output of the frequency multiplier is connected to the input of the power divider, and the output of the power divider is connected to the direct digital frequency synthesizer, the local oscillator generator, and the first signal generation module of the analog mixing unit, respectively.

[0065] The signal generation system provided in this embodiment of the invention includes a signal copying unit in the second signal generation module and a signal switching unit in the signal mixing module. The signal copying unit copies the clock signal generated in the second signal generation module to the signal switching unit. The signal switching unit can select and output the clock signal and the analog local oscillator signal in the second signal generation module. Thus, when switching to the clock signal, the direct digital frequency synthesizer in the analog signal generation unit can be calibrated. When switching to the analog local oscillator signal, the spurious signals introduced into the local oscillator signal are eliminated based on the calibration results of the direct digital frequency synthesizer.

[0066] According to embodiments of the present invention, a signal generation method is provided. It should be noted that the steps shown in the flowcharts can be executed in a computer system such as a set of computer-executable instructions. Furthermore, although a logical order is shown in the flowcharts, in some cases, the steps shown or described may be executed in a different order than that presented here. The following explanation, in conjunction with embodiments of the signal generation method of the present invention, further illustrates the elimination of spurious signals introduced by direct digital frequency synthesizers in signal generation systems.

[0067] This embodiment provides a signal generation method that can be used in the signal generation system described above. Figure 3 This is a flowchart of a signal generation method according to an embodiment of the present invention, such as... Figure 3 As shown, the process includes the following steps:

[0068] Step S301: Determine the reference clock signal frequency based on the preset intermediate frequency signal frequency and the input high frequency signal frequency.

[0069] In this embodiment of the invention, the required analog local oscillator frequency is determined based on the preset intermediate frequency signal frequency and the input high frequency signal frequency, which is the difference between the high frequency signal frequency and the intermediate frequency signal frequency. The reference clock signal frequency is determined based on the required analog local oscillator frequency and the point frequency signal frequency output by the local oscillator generator, which is the difference between the analog local oscillator frequency and the point frequency signal frequency.

[0070] Step S302: Based on the preset correspondence between clock signal frequency and signal power ratio, the reference clock signal frequency is searched to determine the signal power ratio corresponding to the reference clock signal frequency.

[0071] In this embodiment of the invention, the correspondence between clock signal frequency and signal power ratio is obtained by calibrating the signal generation system. When the signal generation system is manufactured or periodically calibrated, the signal switching unit switches to output the clock signal generated by the direct digital frequency synthesizer. At the same time, the direct digital frequency synthesizer is controlled to traverse all target output frequencies according to the minimum frequency interval. After sampling by the analog-to-digital converter, the digital signals corresponding to all target output frequencies are output. The main signal and spurious signal in these digital signals are analyzed respectively, and the power ratio between the main signal and the spurious signal is recorded to obtain the signal power ratio corresponding to each target output frequency, that is, each clock signal frequency. The corresponding relationship is formed and stored to obtain a calibration database.

[0072] In this embodiment of the invention, in the correspondence between clock signal frequency and signal power ratio, the reference clock signal frequency is searched to determine the signal power ratio corresponding to the reference clock signal frequency, and the local oscillator signal is corrected based on the signal power ratio to eliminate spurious signals introduced by the direct digital frequency synthesizer.

[0073] Step S303: If the signal power ratio is not within the preset range, determine the target offset frequency within the preset offset frequency range so that the signal power ratio after the target offset frequency correction is within the preset range.

[0074] In this embodiment of the invention, if the signal power ratio is not within the preset range, it indicates that the reference clock signal frequency will introduce spurious signals. Therefore, a target offset frequency needs to be introduced so that the signal power ratio corresponding to the clock signal frequency corrected based on the target offset frequency is within the preset range, or reaches a preset convergence threshold, thereby eliminating the spurious signals introduced by the clock signal. The boundary of the preset range corresponds to the signal power ratio of the clock signal that will not introduce spurious signals, and it can be customized according to user needs.

[0075] In this embodiment of the invention, the preset offset frequency range corresponds to the frequency interval [a, b], where the values ​​of the lower limit a and the upper limit b are equal to the maximum frequency offset of the signal generation system, and the maximum frequency offset is determined by the sampling intermediate frequency of the analog-to-digital converter.

[0076] In an optional implementation, multiple functional modes can be set, each corresponding to a different preset range, allowing for customization of calibration accuracy. For example, two functional modes with different calibration accuracies can be set. The functional mode with higher calibration accuracy has stricter tolerance requirements, i.e., a more demanding preset range, while the functional mode with lower calibration accuracy has more lenient tolerance requirements, i.e., a less demanding preset range. Alternatively, a custom mode can be set, allowing the user to define the preset range.

[0077] In one optional implementation, the target offset frequency can be determined within a preset offset frequency range in the following manner:

[0078] Step a1: Determine the first offset frequency and the second offset frequency based on the preset offset frequency range.

[0079] The first and second offset frequencies are obtained by calculating the golden section points corresponding to the preset offset frequency range, as shown in the following formula (1):

[0080]

[0081] Formula (1)

[0082] in, The first offset frequency, The second offset frequency, This is the upper limit of the preset offset frequency range. This is the lower limit of the preset offset frequency range.

[0083] Step a2: Based on the first offset frequency and the second offset frequency, the reference clock signal is corrected and searched to obtain the first power ratio corresponding to the first offset frequency and the second power ratio corresponding to the second offset frequency.

[0084] Specifically, the first offset frequency and the second offset frequency are used as target offset frequencies to correct the reference clock signal. That is, the first offset frequency and the second offset frequency are superimposed on the reference clock signal frequency. Based on the correspondence between the clock signal frequency and the signal power ratio, the signal power ratio corresponding to the corrected reference clock signal frequency is used to obtain the first power ratio corresponding to the first offset frequency and the second power ratio corresponding to the second offset frequency.

[0085] Step a3: Update the offset frequency range based on the first power ratio corresponding to the first offset frequency and the second power ratio corresponding to the second offset frequency.

[0086] Specifically, the first power ratio corresponding to the first offset frequency and the second power ratio corresponding to the second offset frequency are compared. If the first power ratio corresponding to the first offset frequency is less than the second power ratio corresponding to the second offset frequency, it indicates that the target offset frequency is located to the left of the second offset frequency. Therefore, the offset frequency range is updated to [a, ...]. If the first power ratio corresponding to the first offset frequency is greater than the second power ratio corresponding to the second offset frequency, it indicates that the target offset frequency is located to the right of the first offset frequency. Therefore, the offset frequency range is updated to []. b).

[0087] Repeat steps a1-a3, that is, update the first offset frequency and the second offset frequency based on the updated offset frequency range, and correct and search the reference clock signal based on the updated first offset frequency and the second offset frequency respectively, update the first power ratio corresponding to the first offset frequency and the second power ratio corresponding to the second offset frequency to update the offset frequency range, until the interval length corresponding to the offset frequency range is less than the preset threshold, that is, less than the set convergence threshold, for example, 1kHz, and determine the middle frequency value of the offset frequency range as the target offset frequency.

[0088] Step S304: Correct the analog local oscillator signal and the digital local oscillator signal based on the target offset frequency.

[0089] In this embodiment of the invention, a target offset frequency signal is superimposed on the reference clock signal. The analog local oscillator signal is then added to the target offset frequency signal to obtain a corrected analog local oscillator signal. The frequency of the corrected analog local oscillator signal is equal to the sum of the analog local oscillator signal frequency and the target offset frequency. The digital local oscillator signal is subtracted from the target offset frequency signal to obtain a corrected digital local oscillator signal. The frequency of the corrected digital local oscillator signal is equal to the difference between the digital local oscillator signal frequency and the target offset frequency. Therefore, the final intermediate frequency (IF) signal frequency is the high-frequency signal frequency minus the analog local oscillator signal frequency minus the target offset frequency. The final output baseband signal frequency is the corrected digital local oscillator signal frequency minus the IF signal frequency, which is the digital local oscillator signal frequency minus the high-frequency signal frequency plus the analog local oscillator signal frequency. This eliminates the spurious signals introduced by the direct digital frequency synthesizer, thus achieving the elimination of spurious signals introduced by the direct digital frequency synthesizer.

[0090] The signal generation method provided in this embodiment of the invention calibrates the signal generation system to obtain the correspondence between the clock signal frequency and the signal power ratio. Based on the correspondence between the clock signal frequency and the signal power ratio, the signal power ratio corresponding to the reference clock signal frequency is determined. Based on the signal power ratio, the target offset frequency is determined within a preset offset frequency range. Thus, the analog local oscillator signal and the digital local oscillator signal are corrected based on the target offset frequency to eliminate spurious signals introduced into the local oscillator signal.

[0091] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and all such modifications and variations fall within the scope defined by the invention.

Claims

1. A signal generation system, characterized in that, The system includes: The first signal generation module is used to generate digital local oscillator signals; The second signal generation module includes: an analog signal generation unit and a signal replication unit; And, a signal mixing module, including: an analog mixing unit, a digital mixing unit, and a signal switching unit; The output terminal of the analog signal generation unit is connected to the input terminal of the analog mixer unit. The first end of the signal copying unit is connected to the clock signal output end of the analog signal generation unit, the second end is connected to the mixer input end of the analog signal generation unit, and the third end is connected to the first end of the signal switching unit. The signal copying unit is used to copy the clock signal generated in the analog signal generation unit to the signal switching unit. The second end of the signal switching unit is connected to the output end of the analog mixer unit, and the third end is connected to the input end of the digital mixer unit.

2. The system according to claim 1, characterized in that, The analog signal generation unit includes a direct digital frequency synthesizer, a local oscillator generator, and a mixer phase-locked loop; The input terminals of the direct digital frequency synthesizer and the local oscillator are respectively connected to reference signals. The direct digital frequency synthesizer is used to generate a clock signal based on the reference signals, and the local oscillator is used to generate a point frequency signal based on the reference signals. The output of the direct digital frequency synthesizer is connected to the first end of the signal replication unit; The first input terminal of the mixing phase-locked loop is connected to the second terminal of the signal replication unit, the second input terminal is connected to the output terminal of the local oscillator generator, and the output terminal is connected to the analog mixing unit.

3. The system according to claim 1, characterized in that, The signal replication unit is a coupler, a power divider, or a switch.

4. The system according to claim 1, characterized in that, The analog mixing unit includes an analog mixer. The first input terminal of the analog mixer is connected to a high-frequency signal, the second input terminal is connected to the output terminal of the analog signal generation unit, and the output terminal is connected to the second terminal of the signal switching unit.

5. The system according to claim 1, characterized in that, The digital mixing unit includes an analog-to-digital converter and a digital mixer; The input terminal of the analog-to-digital converter is connected to the third terminal of the signal switching unit, and the output terminal is connected to the first input terminal of the digital mixer. The second input terminal of the digital mixer is connected to the output terminal of the first signal generation module, and the output terminal outputs a baseband signal.

6. The system according to claim 1, characterized in that, The first signal generation module includes a numerically controlled oscillator; The input terminal of the numerically controlled oscillator is connected to a reference signal, and the output terminal is connected to the digital mixing unit. The numerically controlled oscillator is used to generate a digital local oscillator signal based on the reference signal.

7. The system according to any one of claims 1-6, characterized in that, The system further includes a reference signal generation module, which includes a crystal oscillator, a frequency multiplier, and a power divider. The crystal oscillator is connected to the input terminal of the frequency multiplier, and the output terminal of the frequency multiplier is connected to the input terminal of the power divider. The output of the power divider is connected to the direct digital frequency synthesizer, the local oscillator generator, and the first signal generation module of the analog mixer unit, respectively.

8. A signal generation method, characterized in that, The method, applied to the signal generation system according to any one of claims 1-7, comprises: The reference clock signal frequency is determined based on the preset intermediate frequency signal frequency and the input high frequency signal frequency. Based on a preset correspondence between clock signal frequency and signal power ratio, the reference clock signal frequency is searched to determine the signal power ratio corresponding to the reference clock signal frequency. The correspondence between clock signal frequency and signal power ratio is obtained by calibrating the signal generation system. If the signal power ratio is not within the preset range, a target offset frequency is determined within the preset offset frequency range so that the signal power ratio after the target offset frequency correction is within the preset range; The analog local oscillator signal and the digital local oscillator signal are corrected based on the target offset frequency.

9. The method according to claim 8, characterized in that, Determining the target offset frequency within the preset offset frequency range includes: Based on the preset offset frequency range, the first offset frequency and the second offset frequency are determined; Based on the first offset frequency and the second offset frequency, the reference clock signal is corrected and searched to obtain the first power ratio corresponding to the first offset frequency and the second power ratio corresponding to the second offset frequency. The offset frequency range is updated based on the first power ratio corresponding to the first offset frequency and the second power ratio corresponding to the second offset frequency. Repeat the following steps: Based on the updated offset frequency range, update the first offset frequency and the second offset frequency; based on the updated first offset frequency and the second offset frequency, correct and search the reference clock signal respectively; update the first power ratio corresponding to the first offset frequency and the second power ratio corresponding to the second offset frequency to update the offset frequency range until the interval length corresponding to the offset frequency range is less than a preset threshold; and determine the middle frequency value of the offset frequency range as the target offset frequency.

10. The method according to claim 8, characterized in that, The correction of the analog local oscillator signal and the digital local oscillator signal based on the target offset frequency includes: The simulated local oscillator signal is added to the signal at the target offset frequency to obtain the corrected simulated local oscillator signal; The corrected digital local oscillator signal is obtained by subtracting the signal at the target offset frequency from the digital local oscillator signal.

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