Signal generation system and method

Abstract

The invention relates to the technical field of signal generation, and discloses a signal generation system and method.In a frequency mixing and phase locking module, the first input end of a frequency mixing unit is connected with the output end of a dot frequency selection unit, the second input end of the frequency mixing unit is connected with the output end of a signal adjustment unit, and the output end of the frequency mixing unit is connected with the input end of a sideband selection unit; the first input end of the signal adjusting unit is connected with the output end of the sideband selection unit, and the second input end is connected with the output end of the frequency synthesis module; the input end of the dot frequency selection unit is connected with the output end of the dot frequency generation module; the input end of the frequency synthesis module is connected with the output end of the dot frequency generation module. Therefore, the frequency band coverage of a single dot frequency signal is expanded through a sideband switching mode, the number of required dot frequency signals is reduced, the number of required filters is reduced, the hardware complexity of a system is reduced, meanwhile, the frequency interval of the dot frequency signals can be expanded, the transition band requirement of the filters is reduced, and the signal-to-noise ratio of the system is improved.

Description

A signal generation system and method 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] To generate a continuous local oscillator signal covering 3GHz to 9GHz, a fine variable frequency source covering 500-1000MHz and a set of point frequency signals are typically used for mixing. In order to ensure seamless coverage of the entire frequency band after mixing, the frequency spacing of the point frequency signals must be less than or equal to the bandwidth of the fine frequency source. The filter needs to provide 40-50dB of suppression for other nearby point frequency signals within an extremely narrow transition band, which results in extremely high Q value requirements for the filter, leading to high insertion loss and deterioration of the system noise performance. At the same time, each point frequency signal requires a separate set of filters, resulting in high hardware complexity of the system. Summary of the Invention

[0003] This invention provides a signal generation system and method to solve the problems of low signal-to-noise ratio and high hardware complexity.

[0004] In a first aspect, the present invention provides a signal generation system, comprising: a frequency generation module, a frequency synthesis module, and a mixing phase-locked loop module; wherein the mixing phase-locked loop module comprises: a frequency selection unit, a sideband selection unit, a mixing unit, and a signal adjustment unit; a first input terminal of the mixing unit is connected to the output terminal of the frequency selection unit, a second input terminal is connected to the output terminal of the signal adjustment unit, and the output terminal is connected to the input terminal of the sideband selection unit; a first input terminal of the signal adjustment unit is connected to the output terminal of the sideband selection unit, and a second input terminal is connected to the output terminal of the frequency synthesis module; an input terminal of the frequency selection unit is connected to the output terminal of the frequency generation module; and an input terminal of the frequency synthesis module is connected to the output terminal of the frequency generation module.

[0005] In one optional implementation, the point frequency selection unit includes a set of narrowband filter banks, wherein the center frequencies of each narrowband filter in the set of narrowband filter banks have a preset frequency difference.

[0006] In one optional embodiment, the sideband selection unit includes a first switch, a second switch, a first filter, and a second filter; wherein the input terminal of the first switch is connected to the output terminal of the mixer unit, and the output terminal is connected to the input terminals of the first filter and the second filter, respectively; the input terminal of the second switch is connected to the output terminals of the first filter and the second filter, respectively, and the output terminal is connected to the first input terminal of the signal adjustment unit.

[0007] In one optional implementation, the signal adjustment unit includes a phase detector, a loop filter, and a voltage-controlled oscillator (VCO); wherein, the first input terminal of the phase detector is connected to the output terminal of the sideband selection unit, the second input terminal is connected to the output terminal of the frequency synthesis module, and the output terminal is connected to the input terminal of the loop filter; the output terminal of the loop filter is connected to the input terminal of the VCO, and the output terminal of the VCO is connected to the second input terminal of the mixer unit.

[0008] In one optional implementation, the signal adjustment unit further includes a coupler; the input terminal of the coupler is connected to the output terminal of the voltage-controlled oscillator, the first output terminal is connected to the second input terminal of the mixer unit, and the second output terminal is used to output the local oscillator signal.

[0009] In one optional implementation, the point frequency generation module includes a crystal oscillator, a frequency multiplier, and a comb spectrum generator; wherein the output terminal of the crystal oscillator is connected to the input terminal of the frequency multiplier, the output terminal of the frequency multiplier is connected to the input terminal of the comb spectrum generator, and the output terminal of the comb spectrum generator is connected to the input terminal of the frequency synthesis module and the input terminal of the point frequency selection unit, respectively.

[0010] In one optional implementation, the point frequency generation module further includes a narrowband filter and a high-pass filter; wherein, the input terminal of the narrowband filter is connected to the output terminal of the frequency multiplier, and the output terminal is connected to the input terminal of the comb spectrum generator; the input terminal of the high-pass filter is connected to the output terminal of the comb spectrum generator, and the output terminal is connected to the input terminal of the frequency synthesis module and the input terminal of the point frequency selection unit, respectively.

[0011] In one optional implementation, the point frequency generation module further includes a power divider; the input terminal of the power divider is connected to the output terminal of the high-pass filter, the first output terminal is connected to the input terminal of the frequency synthesis module, and the second output terminal is connected to the input terminal of the point frequency selection unit.

[0012] In one optional implementation, the frequency synthesis module includes a narrowband filter and a frequency synthesizer; wherein the input terminal of the narrowband filter is connected to the output terminal of the point frequency generation module, the output terminal of the narrowband filter is connected to the input terminal of the frequency synthesizer, and the output terminal of the frequency synthesizer is connected to the second input terminal of the signal adjustment unit.

[0013] 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 includes: controlling a point frequency selection unit to output a target point frequency signal from a set of point frequency signals output by a point frequency generation module to a mixing unit, so that the mixing unit mixes the target point frequency signal and a first local oscillator signal output by a signal adjustment unit to obtain a first difference frequency signal and a second difference frequency signal; controlling a sideband selection unit to select the first difference frequency signal or the second difference frequency signal to output to a signal adjustment unit, so that the signal adjustment unit adjusts the first local oscillator signal based on the first difference frequency signal or the second difference frequency signal to obtain a target local oscillator signal.

[0014] The signal generation system provided in this embodiment of the invention uses a point frequency selection unit connected to a point frequency generation module. It selects a point frequency signal from a set of point frequency signals output by the point frequency generation module, uses a mixing unit to mix the selected signal with the local oscillator signal output by the signal adjustment unit, and uses a sideband selection unit to select the difference frequency signal output by the mixing unit. This expands the bandwidth coverage of a single point frequency signal through sideband switching, thereby reducing the number of required point frequency signals and consequently the number of required filters, reducing the hardware complexity of the system. Simultaneously, it expands the frequency interval of the point frequency signals, reducing the transition band requirements of the filters, facilitating high suppression and low insertion loss, and ultimately improving the system's signal-to-noise ratio. Attached Figure Description

[0015] 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.

[0016] Figure 1 is a structural schematic diagram of a signal generation system according to an embodiment of the present invention; Figure 2 is an architectural schematic diagram of a signal generation system according to an embodiment of the present invention; Figure 3 is a flowchart of a signal generation method according to an embodiment of the present invention.

[0017] Explanation of reference numerals in the attached diagram: 1. Frequency generation module; 2. Frequency synthesis module; 3. Mixing and phase-locked loop module; 31. Frequency selection unit; 32. Sideband selection unit; 33. Mixing unit; 34. Signal adjustment unit. Detailed Implementation

[0018] 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.

[0019] 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.

[0020] 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.

[0021] To generate a continuous local oscillator signal covering 3GHz to 9GHz, a finely variable frequency source covering 500-1000MHz and a set of point frequency signals are typically used for mixing. In order to ensure seamless coverage of the entire frequency band after mixing, the frequency spacing of the point frequency signals must be less than or equal to the bandwidth of the fine frequency source. Therefore, at least 12 point frequency signals are required, such as 3.0GHz, 3.5GHz, 4.0GHz, ..., 8.5GHz. At the same time, the filter needs to provide 40-50dB of suppression for other adjacent point frequency signals within an extremely narrow transition band, which results in extremely high Q value requirements for the filter, leading to high insertion loss and deterioration of the system noise performance. In addition, each point frequency signal requires a separate set of filters, resulting in high hardware complexity of the system.

[0022] Based on this, the present invention provides a signal generation system, which includes: a frequency generation module, a frequency synthesis module, and a mixing phase-locked loop module; wherein, the mixing phase-locked loop module includes: a frequency selection unit, a sideband selection unit, a mixing unit, and a signal adjustment unit; the first input terminal of the mixing unit is connected to the output terminal of the frequency selection unit, the second input terminal is connected to the output terminal of the signal adjustment unit, and the output terminal is connected to the input terminal of the sideband selection unit; the first input terminal of the signal adjustment unit is connected to the output terminal of the sideband selection unit, and the second input terminal is connected to the output terminal of the frequency synthesis module; the input terminal of the frequency selection unit is connected to the output terminal of the frequency generation module; and the input terminal of the frequency synthesis module is connected to the output terminal of the frequency generation module. A point frequency selection unit is connected to the point frequency generation module. A point frequency signal is selected from a group of point frequency signals output by the point frequency generation module. A mixing unit mixes the selected mixing signal with the local oscillator signal output by the signal adjustment unit. A sideband selection unit selects the difference frequency signal output by the mixing unit. By switching sidebands, the frequency band coverage of a single point frequency signal is expanded, thereby reducing the number of required point frequency signals, which in turn reduces the number of required filters and reduces the hardware complexity of the system. At the same time, it can expand the frequency interval of the point frequency signals, which reduces the transition band requirements of the filters, making it easier to achieve high rejection and low insertion loss, thereby improving the system signal-to-noise ratio.

[0023] According to an embodiment of the present invention, a signal generation system is provided. Figure 1 is a schematic diagram of the signal generation system according to an embodiment of the present invention. As shown in Figure 1, the system includes: a point frequency generation module 1, a frequency synthesis module 2, and a mixing phase-locked loop module 3. The point frequency generation module 1 generates a set of point frequency signals, thereby generating a continuous local oscillator signal based on the set of point frequency signals. The frequency synthesis module 2 generates a frequency signal, which serves as the frequency reference for the phase-locked loop formed by the mixing phase-locked loop module 3, enabling the mixing phase-locked loop module 3 to perform fine-tuning of the local oscillator frequency based on the frequency signal, thereby obtaining a precise local oscillator signal.

[0024] In this embodiment of the invention, as shown in FIG1, the mixing phase-locked module 3 includes: a point frequency selection unit 31, a sideband selection unit 32, a mixing unit 33, and a signal adjustment unit 34. The point frequency selection unit 31 is connected to the point frequency generation module 1 and is used to sequentially select a point frequency signal from a set of point frequency signals generated by the point frequency generation module 1. The mixing unit 33 is used to mix the point frequency signal selected by the point frequency selection unit 31 with the signal output by the signal adjustment unit 34, and output the corresponding mixed signal. The sideband selection unit 32 selects a difference frequency signal from the mixed signal output by the mixing unit 33 and outputs it to the signal adjustment unit 34, so that the signal adjustment unit 34, based on the signal selected and output by the sideband selection unit 32, and combined with the frequency signal generated by the frequency synthesis module 2, adjusts the local oscillator frequency to obtain a precise local oscillator signal.

[0025] Specifically, as shown in Figure 1, the first input terminal of the mixing unit 33 is connected to the output terminal of the spot frequency selection unit 31, the second input terminal is connected to the output terminal of the signal adjustment unit 34, and the output terminal is connected to the input terminal of the sideband selection unit 32; the first input terminal of the signal adjustment unit 34 is connected to the output terminal of the sideband selection unit 32, and the second input terminal is connected to the output terminal of the frequency synthesis module 2; the input terminal of the spot frequency selection unit 31 is connected to the output terminal of the spot frequency generation module 1; and the input terminal of the frequency synthesis module 2 is connected to the output terminal of the spot frequency generation module 1.

[0026] In one optional implementation, the mixing unit 33 may be composed of a mixer, with the two input terminals of the mixer connected to the output terminal of the frequency selection unit 31 and the output terminal of the signal adjustment unit 34, respectively, and the output terminal of the mixer connected to the input terminal of the sideband selection unit 32.

[0027] In an optional implementation, FIG2 is a schematic diagram of the architecture of a signal generation system according to an embodiment of the present invention. As shown in FIG2, the sideband selection unit 32 may include a first switch, a second switch, a first filter, and a second filter. The first filter and the second filter may be narrowband filters, which filter out the sum frequency signal in the mixed signal output by the mixer, retaining only the difference frequency signal. The input terminal of the first switch is connected to the output terminal of the mixing unit 33, and its output terminal is connected to the input terminals of the first filter and the second filter, respectively. The input terminal of the second switch is connected to the output terminals of the first filter and the second filter, respectively, and its output terminal is connected to the first input terminal of the signal adjustment unit 34. By controlling the first switch and the second switch, the switching between high sideband injection and ground sideband injection of the mixed signal is realized. For example, the first switch controls low sideband injection, and the second switch controls high sideband injection. When low sideband injection is selected, the first switch is closed and the second switch is open; when high sideband injection is selected, the first switch is open and the second switch is closed. Therefore, by fully utilizing the two difference frequency signals of each point frequency signal through sideband switching, the bandwidth coverage of a single point frequency signal is doubled, thereby reducing the number of point frequency signals used by half. At the same time, the frequency interval of the point frequency signals can be expanded, which reduces the transition band requirements of the filter, makes it easier to achieve high suppression and low insertion loss, and thus improves the system signal-to-noise ratio.

[0028] In one optional implementation, as shown in FIG2, the point frequency selection unit 31 includes a set of narrowband filter banks. The center frequencies of each narrowband filter in the set of narrowband filter banks have a preset frequency difference, and the center frequency of each narrowband filter corresponds one-to-one with the frequency of a set of point frequency signals generated by the point frequency generation module 1. For example, if the required continuous local oscillator signal covers a frequency range of 3GHz to 9GHz, then the frequencies of the set of point frequency signals generated by the point frequency generation module 1 are 3.5GHz, 4.5GHz, ..., 8.5GHz, respectively. Then, the set of narrowband filters includes 6 narrowband filters, and the center frequencies of each narrowband filter are 3.5GHz, 4.5GHz, ..., 8.5GHz, respectively, that is, the preset frequency difference is 1GHz.

[0029] In an alternative implementation, although not explicitly shown in FIG2, the point frequency selection unit 31 may further include a switch for selecting the narrowband filter therein. By controlling the switch to select the narrowband filter corresponding to the center frequency, a point frequency signal currently being generated for local oscillator signal is selected and output to the mixing unit 33.

[0030] In one optional implementation, as shown in Figure 2, the signal adjustment unit 34 includes a phase detector, a loop filter, and a voltage-controlled oscillator (VCO). The first input terminal of the phase detector is connected to the output terminal of the sideband selection unit 32, the second input terminal is connected to the output terminal of the frequency synthesis module 2, and the output terminal is connected to the input terminal of the loop filter. The phase detector compares the phase difference between the difference frequency signal selected and output by the sideband selection unit 32 and the frequency signal output by the frequency synthesis module 2, using the frequency signal as a reference, and outputs a voltage signal that characterizes the phase difference, which is proportional to the phase difference. The output terminal of the loop filter is connected to the input terminal of the VCO. The loop filter removes high-frequency spurious signals and noise from the voltage signal output by the phase detector, resulting in a smooth DC control voltage to ensure the stability of the local oscillator signal generated by the VCO. Simultaneously, the output terminal of the VCO is connected to the second input terminal of the mixer unit 33, feeding back the generated local oscillator signal to the mixer unit 33, thereby forming a phase-locked loop (PLL) between the signal adjustment unit 34, the mixer unit 33, and the sideband selection unit 32.

[0031] In an optional implementation, as shown in FIG2, the signal adjustment unit 34 further includes a coupler. The input terminal of the coupler is connected to the output terminal of the voltage-controlled oscillator (VCO), and the first output terminal is connected to the second input terminal of the mixer unit 33. The second output terminal is used to output the local oscillator signal. The coupler separates the local oscillator signal generated by the VCO into two signals. One signal contains most of the local oscillator signal generated by the VCO and is output from the second output terminal. The other signal contains a small portion of the local oscillator signal generated by the VCO and is output from the first output terminal to the mixer unit 33, thus forming a closed-loop signal circuit of the phase-locked loop.

[0032] In one optional implementation, as shown in Figure 2, the frequency generation module 1 includes a crystal oscillator, a frequency multiplier, and a comb spectrum generator. The crystal oscillator generates a fundamental signal with stable frequency and low phase noise. The output of the crystal oscillator is connected to the input of the frequency multiplier, allowing the fundamental signal to be multiplied to raise the signal frequency to the desired band. The output of the frequency multiplier is connected to the input of the comb spectrum generator, which generates odd harmonic signals. The output of the comb spectrum generator is connected to the inputs of the frequency synthesis module 2 and the frequency selection unit 31, respectively, outputting the generated signals to both the frequency synthesis module 2 and the frequency selection unit 31.

[0033] In an optional implementation, as shown in Figure 2, the point frequency generation module 1 further includes a narrowband filter and a high-pass filter. The input of the narrowband filter is connected to the output of the frequency multiplier, and its output is connected to the input of the comb spectrum generator. The narrowband filter is used to filter out harmonics and noise in the signal output by the frequency multiplier. The input of the high-pass filter is connected to the output of the comb spectrum generator, and its output is connected to the input of the frequency synthesis module 2 and the input of the point frequency selection unit 31, respectively. The high-pass filter is used to filter out low-frequency components in the odd-order harmonic signals generated by the comb spectrum generator, retaining the final point frequency signal.

[0034] For example, a crystal oscillator generates a 100MHz fundamental signal. A 5x frequency multiplier is selected to boost the fundamental signal to 500MHz. Then, a narrowband filter is used to filter out harmonics and noise in the signal output from the frequency multiplier before inputting it to a comb spectrum generator. The comb spectrum generator generates a set of odd harmonic point frequency signals with a frequency interval of 1GHz based on the 500MHz signal. The signal frequencies are 1.5GHz, 2.5GHz, 3.5GHz, 4.5GHz, ..., 8.5GHz. Finally, a high-pass filter is used to filter out the low-frequency components, forming the final point frequency signal with frequencies of 3.5GHz, 4.5GHz, ..., 8.5GHz.

[0035] In one alternative implementation, the comb spectrum generator may be an odd-order comb spectrum generator, or a comb spectrum generator based on a step recovery diode, or a frequency generator composed of multiple phase-locked loops may be used instead of the comb spectrum generator. The specific method for generating odd-order harmonic signals is not specifically limited here.

[0036] In one optional implementation, as shown in Figure 2, the point frequency generation module 1 further includes a power divider, which splits the point frequency signal into two paths and outputs them to the frequency synthesis module 2 and the point frequency selection unit 31, respectively. The input terminal of the power divider is connected to the output terminal of the high-pass filter, the first output terminal is connected to the input terminal of the frequency synthesis module 2, and the second output terminal is connected to the input terminal of the point frequency selection unit 31.

[0037] In one optional implementation, as shown in FIG2, the frequency synthesis module 2 includes a narrowband filter and a frequency synthesizer. The input terminal of the narrowband filter is connected to the output terminal of the point frequency generation module 1, the output terminal of the narrowband filter is connected to the input terminal of the frequency synthesizer, and the output terminal of the frequency synthesizer is connected to the second input terminal of the signal adjustment unit 34.

[0038] In one alternative implementation, a Direct Digital Synthesizer (DDS) can be used as the frequency synthesizer, or a scheme that can output a finely variable frequency, such as a fractional frequency division phase-locked loop, can be used instead of the frequency synthesizer. No specific limitation is made here.

[0039] The signal generation system provided in this embodiment of the invention includes: a frequency generation module, a frequency synthesis module, and a mixing phase-locked loop module; wherein, the mixing phase-locked loop module includes: a frequency selection unit, a sideband selection unit, a mixing unit, and a signal adjustment unit; the first input terminal of the mixing unit is connected to the output terminal of the frequency selection unit, the second input terminal is connected to the output terminal of the signal adjustment unit, and the output terminal is connected to the input terminal of the sideband selection unit; the first input terminal of the signal adjustment unit is connected to the output terminal of the sideband selection unit, and the second input terminal is connected to the output terminal of the frequency synthesis module; the input terminal of the frequency selection unit is connected to the output terminal of the frequency generation module; and the input terminal of the frequency synthesis module is connected to the output terminal of the frequency generation module. A point frequency selection unit is connected to the point frequency generation module. A point frequency signal is selected from a group of point frequency signals output by the point frequency generation module. A mixing unit mixes the selected mixing signal with the local oscillator signal output by the signal adjustment unit. A sideband selection unit selects the difference frequency signal output by the mixing unit. By switching sidebands, the frequency band coverage of a single point frequency signal is expanded, thereby reducing the number of required point frequency signals, which in turn reduces the number of required filters and reduces the hardware complexity of the system. At the same time, it can expand the frequency interval of the point frequency signals, which reduces the transition band requirements of the filters, making it easier to achieve high rejection and low insertion loss, thereby improving the system signal-to-noise ratio.

[0040] According to an embodiment of the present invention, a signal generation method embodiment is provided. It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Furthermore, although a logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order than that shown here.

[0041] This embodiment provides a signal generation method that can be used in the signal generation system described above. Figure 3 is a schematic flowchart of the signal generation method according to an embodiment of the present invention. As shown in Figure 3, the process includes the following steps: Step S301, the control point frequency selection unit 31 outputs a target point frequency signal from a set of point frequency signals output by the point frequency generation module 1 to the mixing unit 33, so that the mixing unit 33 mixes the target point frequency signal and the first local oscillator signal output by the signal adjustment unit 34 to obtain a first difference frequency signal and a second difference frequency signal.

[0042] In this embodiment of the invention, after the point frequency generation module 1 generates a set of point frequency signals, the control point frequency selection unit 31 sequentially selects one point frequency signal from the set as the target point frequency signal and outputs it to the mixing unit 33, so that the signal generation system generates a local oscillator signal based on the target point frequency signal. After the control point frequency selection unit 31 outputs all point frequency signals in the set as target point frequency signals to the mixing unit 33, the signal generation system outputs the required complete continuous local oscillator signal.

[0043] In this embodiment of the invention, after the control frequency signal outputs the target frequency signal to the mixing unit 33, the mixing unit 33 performs mixing based on the target frequency signal and the first local oscillator signal output by the signal adjustment unit 34. The resulting mixed signal includes a sum frequency signal (i.e., a signal whose frequency is the sum of the two frequencies) and a difference frequency signal (i.e., a signal whose frequency is the difference between the two frequencies). The difference frequency signal is selected as the output. The difference frequency signal further includes a first difference frequency signal and a second difference frequency signal. The first difference frequency signal is a signal whose frequency is the difference between the target frequency signal and the first local oscillator signal, and the second difference frequency signal is a signal whose frequency is the difference between the first local oscillator signal and the target frequency signal.

[0044] In one optional implementation, by controlling the switches in the frequency selection unit 31, a narrowband filter whose center frequency matches the target frequency signal is selected, and the target frequency signal is output to the mixing unit 33. Controlling the switches in the frequency selection unit 31 can involve closing the switch corresponding to the narrowband filter whose center frequency matches the target frequency signal, and opening other switches.

[0045] In step S302, the control sideband selection unit 32 selects either the first difference frequency signal or the second difference frequency signal to output to the signal adjustment unit 34, so that the signal adjustment unit 34 adjusts the first local oscillator signal based on the first difference frequency signal or the second difference frequency signal to obtain the target local oscillator signal.

[0046] In this embodiment of the invention, the control sideband selection unit 32 selects either a first difference frequency signal or a second difference frequency signal to output to the signal adjustment unit 34. Specifically, if low sideband injection is selected, the first difference frequency signal is selected to output to the signal adjustment unit 34; if high sideband injection is selected, the second difference frequency signal is selected to output to the signal adjustment unit 34. By sequentially selecting the first and second difference frequency signals to output to the signal adjustment unit 34, the signal adjustment unit 34 adjusts the local oscillator signal based on the first and second difference frequency signals respectively, thereby obtaining the target local oscillator signal. That is, the local oscillator signal corresponding to a single-frequency signal includes the local oscillator signals corresponding to its corresponding first and second difference frequency signals.

[0047] In this embodiment of the invention, the mixing unit 33, the sideband selection unit 32, and the signal adjustment unit 34 form a phase-locked loop to lock the frequency difference between the first local oscillator signal and the target point frequency signal at the frequency of the frequency signal output by the frequency synthesizer, thereby obtaining the desired target local oscillator signal. That is, for a point frequency signal, the frequency of the final output local oscillator signal is the difference between the frequency of the point frequency signal and the frequency signal, and the sum of the frequencies of the point frequency signal and the frequency signal.

[0048] For example, if the frequency selection unit 31 outputs a frequency signal of 4.5 GHz, i.e., selects a narrowband filter with a center frequency of 4.5 GHz, and the target frequency signal output is 4.5 GHz, and the frequency synthesis module 2 generates a fine frequency signal that is continuously variable within the range of 500 MHz to 1000 MHz, then when selecting low sideband injection (i.e., when the sideband selection unit 32 selects the first difference frequency signal), the frequency range of the local oscillator signal output after phase locking is 3.5 GHz to 4 GHz. When selecting high sideband injection (i.e., when the sideband selection unit 32 selects the second difference frequency signal), the frequency range of the local oscillator signal output after phase locking is 5 GHz. -5.5GHz, meaning that for a 4.5GHz point frequency signal, it achieves a continuous frequency band covering 1GHz from 3.5GHz to 4.0GHz (low sideband) and from 5.0GHz to 5.5GHz (high sideband). Thus, the signal generation method provided by this invention can achieve continuous coverage from 3.5GHz to 8.5GHz using only 6 point frequency signals, reducing the number of required point frequency signals, thereby reducing the number of required filters and reducing the hardware complexity of the system. At the same time, it can extend the frequency interval of the point frequency signals, reducing the transition band requirements of the filters, making it easier to achieve high suppression and low insertion loss, thereby improving the system signal-to-noise ratio.

[0049] 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 such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A signal generation system, characterized in that, The system includes: a frequency generation module (1), a frequency synthesis module (2), and a mixing phase-locked loop module (3); wherein, the mixing phase-locked loop module (3) includes: a frequency selection unit (31), a sideband selection unit (32), a mixing unit (33), and a signal adjustment unit (34); the first input terminal of the mixing unit (33) is connected to the output terminal of the frequency selection unit (31), the second input terminal is connected to the output terminal of the signal adjustment unit (34), and the output terminal is connected to the input terminal of the sideband selection unit (32); the first input terminal of the signal adjustment unit (34) is connected to the output terminal of the sideband selection unit (32), and the second input terminal is connected to the output terminal of the frequency synthesis module (2); the input terminal of the frequency selection unit (31) is connected to the output terminal of the frequency generation module (1); the input terminal of the frequency synthesis module (2) is connected to the output terminal of the frequency generation module (1).

2. The system according to claim 1, characterized in that, The point frequency selection unit (31) includes a set of narrowband filter groups, and the center frequencies of each narrowband filter in the set of narrowband filter groups have a preset frequency difference.

3. The system according to claim 1, characterized in that, The sideband selection unit (32) includes a first switch, a second switch, a first filter, and a second filter; wherein, the input terminal of the first switch is connected to the output terminal of the mixer unit (33), and the output terminal is connected to the input terminal of the first filter and the input terminal of the second filter respectively; the input terminal of the second switch is connected to the output terminal of the first filter and the output terminal of the second filter respectively, and the output terminal is connected to the first input terminal of the signal adjustment unit (34).

4. The system according to claim 1, characterized in that, The signal adjustment unit (34) includes a phase detector, a loop filter, and a voltage-controlled oscillator; wherein, the first input terminal of the phase detector is connected to the output terminal of the sideband selection unit (32), the second input terminal is connected to the output terminal of the frequency synthesis module (2), and the output terminal is connected to the input terminal of the loop filter; the output terminal of the loop filter is connected to the input terminal of the voltage-controlled oscillator, and the output terminal of the voltage-controlled oscillator is connected to the second input terminal of the mixer unit (33).

5. The system according to claim 4, characterized in that, The signal adjustment unit (34) further includes a coupler; the input end of the coupler is connected to the output end of the voltage-controlled oscillator, the first output end is connected to the second input end of the mixer unit (33), and the second output end is used to output the local oscillator signal.

6. The system according to claim 1, characterized in that, The point frequency generation module (1) includes a crystal oscillator, a frequency multiplier, and a comb spectrum generator; wherein, the output terminal of the crystal oscillator is connected to the input terminal of the frequency multiplier, the output terminal of the frequency multiplier is connected to the input terminal of the comb spectrum generator, and the output terminal of the comb spectrum generator is connected to the input terminal of the frequency synthesis module (2) and the input terminal of the point frequency selection unit (31), respectively.

7. The system according to claim 6, characterized in that, The point frequency generation module (1) further includes a narrowband filter and a high-pass filter; wherein, the input end of the narrowband filter is connected to the output end of the frequency multiplier, and the output end is connected to the input end of the comb spectrum generator; the input end of the high-pass filter is connected to the output end of the comb spectrum generator, and the output end is connected to the input end of the frequency synthesis module (2) and the input end of the point frequency selection unit (31), respectively.

8. The system according to claim 7, characterized in that, The point frequency generation module (1) also includes a power divider; the input terminal of the power divider is connected to the output terminal of the high-pass filter, the first output terminal is connected to the input terminal of the frequency synthesis module (2), and the second output terminal is connected to the input terminal of the point frequency selection unit (31).

9. The system according to claim 1, characterized in that, The frequency synthesis module (2) includes a narrowband filter and a frequency synthesizer; wherein, the input end of the narrowband filter is connected to the output end of the point frequency generation module (1), the output end of the narrowband filter is connected to the input end of the frequency synthesizer, and the output end of the frequency synthesizer is connected to the second input end of the signal adjustment unit (34).

10. A signal generation method, characterized in that, Applied to the signal generation system of claims 1-9, the method includes: controlling the point frequency selection unit (31) to output a target point frequency signal from a set of point frequency signals output by the point frequency generation module (1) to the mixing unit (33), so that the mixing unit (33) mixes the target point frequency signal and the first local oscillator signal output by the signal adjustment unit (34) to obtain a first difference frequency signal and a second difference frequency signal; controlling the sideband selection unit (32) to select the first difference frequency signal or the second difference frequency signal to output to the signal adjustment unit (34), so that the signal adjustment unit (34) adjusts the first local oscillator signal based on the first difference frequency signal or the second difference frequency signal to obtain the target local oscillator signal.

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