Radio frequency excitation source and radio frequency system
The RF excitation source designed through FPGA, combined with the frequency adjustment module and waveform generation module, solves the problems of low frequency resolution and high power consumption caused by the high main frequency reference clock, and realizes an RF excitation source with higher frequency resolution and lower power consumption.
Patent Information
- Application Number
- CN202410351672.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-03-26
- Publication Date
- 2025-09-26
AI Technical Summary
When using a high-frequency reference clock, the existing RF excitation source requires a high-quality clock chip, resulting in low frequency resolution, high area power consumption, and high-frequency reference clock increases circuit power consumption.
The RF excitation source is designed using FPGA. The frequency adjustment module is combined with the waveform generation module. The frequency adjustment circuit and waveform lookup table are used to generate the target waveform, reduce the reference clock frequency, reduce phase spurs, and improve frequency resolution.
Improves phase spurs at lower reference clocks, significantly reduces area and power consumption, and improves frequency resolution and signal quality.
Smart Images
Figure CN120704471A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of radio frequency technology, and in particular to a radio frequency excitation source and a radio frequency system. Background Art
[0002] An RF system is a system comprised of a series of RF devices and components that handles the transmission, modulation, demodulation, amplification, filtering, and reception of RF signals. RF systems are widely used in communications, radar, satellite communications, medical equipment, aerospace, and other fields. The RF excitation source is a crucial component of an RF system, primarily used to generate RF signals.
[0003] When using existing RF excitation sources, direct digital synthesis is often performed by adopting a high-frequency reference clock method to reduce the size of the phase error generated by a single shot, thereby reducing phase spurious. However, in order to obtain a high-frequency reference clock, it is often necessary to introduce a high-quality clock chip. In addition, the high-frequency reference clock will also bring more power consumption to the circuit, resulting in low frequency resolution and high area power consumption when using existing RF excitation sources. Summary of the Invention
[0004] To address the above issues, the present application provides a radio frequency excitation source comprising: a clock management module, a communication module, a frequency adjustment module, a waveform generation module, and a waveform output module; the output of the clock management module is connected to the inputs of the communication module, the frequency adjustment module, the waveform generation module, and the waveform output module, respectively; the output of the communication module is connected to the inputs of the frequency adjustment module and the waveform generation module, respectively; the output of the frequency adjustment module is connected to the input of the waveform generation module; and the output of the waveform generation module is connected to the input of the waveform output module. By combining the frequency adjustment module with the waveform generation module, the present application can improve phase stray signals at lower reference clocks, while obtaining an excitation signal with higher frequency resolution and significantly reducing area and power consumption.
[0005] In a first aspect, an embodiment of the present application provides a radio frequency excitation source, comprising: a clock management module, a communication module, a frequency adjustment module, a waveform generation module and a waveform output module; the output end of the clock management module is respectively connected to the input ends of the communication module, the frequency adjustment module, the waveform generation module and the waveform output module; the output end of the communication module is respectively connected to the input ends of the frequency adjustment module and the waveform generation module; the output end of the frequency adjustment module is connected to the input end of the waveform generation module; and the output end of the waveform generation module is connected to the input end of the waveform output module.
[0006] In a second aspect, an embodiment of the present application provides a radio frequency system, comprising the radio frequency excitation source described in the first aspect above.
[0007] The technical solutions provided in the embodiments of this application have at least the following technical effects or advantages:
[0008] The RF excitation source of the embodiment of the present application includes: a clock management module, a communication module, a frequency adjustment module, a waveform generation module, and a waveform output module; the output end of the clock management module is respectively connected to the input ends of the communication module, the frequency adjustment module, the waveform generation module, and the waveform output module; the output end of the communication module is respectively connected to the input ends of the frequency adjustment module and the waveform generation module; the output end of the frequency adjustment module is connected to the input end of the waveform generation module; and the output end of the waveform generation module is connected to the input end of the waveform output module. By combining the frequency adjustment module with the waveform generation module, the present application can improve the phase spurious problem at a lower reference clock, while obtaining an excitation signal with higher frequency resolution and significantly reducing area power consumption.
[0009] Additional aspects and advantages of the present application will be given in part in the description below and in part will become apparent from the description below or learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS
[0010] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present application. The same reference symbols are used throughout the drawings to represent the same components. In the drawings:
[0011] Figure 1 A schematic structural diagram of a radio frequency excitation source provided in an embodiment of the present application is shown;
[0012] Figure 2 A schematic diagram showing a structure of a frequency modulator generating a third adjustment coefficient provided in an embodiment of the present application is shown;
[0013] Figure 3 A comparison diagram of target waveforms generated by the RF excitation source provided by the embodiment of the present application and the RF excitation source of the prior art is shown. DETAILED DESCRIPTION
[0014] The following describes exemplary embodiments of the present application in more detail with reference to the accompanying drawings. Although exemplary embodiments of the present application are shown in the accompanying drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments described herein. Instead, these embodiments are provided to enable a more thorough understanding of the present application and to fully convey the scope of the present application to those skilled in the art.
[0015] When using existing RF excitation sources, direct digital synthesis is often performed by adopting a high-frequency reference clock method to reduce the size of the phase error generated by a single shot, thereby reducing phase spurious. However, in order to obtain a high-frequency reference clock, it is often necessary to introduce a high-quality clock chip. In addition, the high-frequency reference clock will also bring more power consumption to the circuit, resulting in low frequency resolution and high area power consumption when using existing RF excitation sources.
[0016] Based on this, an embodiment of the present application provides a radio frequency excitation source. An FPGA (Field-Programmable Gate Array) is used for circuit design. A frequency adjustment circuit is established based on the relationship between the target frequency and the frequency adjustment coefficient. The target frequency is then adjusted according to the frequency adjustment module. Phase accumulation is performed according to the adjusted frequency. The waveform index corresponding to the waveform lookup table in the waveform generation module is obtained based on the phase accumulation result. The corresponding target waveform is then found based on the waveform index and transmitted to the waveform output module in the form of a digital signal. Finally, the target waveform is output in the form of an analog signal. The scheme of the embodiment of the present application is described in detail below with reference to the accompanying drawings.
[0017] See also Figure 1 The structural schematic diagram of a radio frequency excitation source shown specifically includes: a clock management module, a communication module, a frequency adjustment module, a waveform generation module and a waveform output module; the output end of the clock management module is respectively connected to the input end of the communication module, the frequency adjustment module, the waveform generation module and the waveform output module; the output end of the communication module is respectively connected to the input end of the frequency adjustment module and the waveform generation module; the output end of the frequency adjustment module is connected to the input end of the waveform generation module; and the output end of the waveform generation module is connected to the input end of the waveform output module.
[0018] Based on the above embodiments, in some modified implementations, the frequency adjustment module may include a divider and a frequency modulator; the output end of the communication module is connected to the input end of the divider; the output end of the divider is connected to the input end of the frequency modulator; and the output end of the frequency modulator is connected to the input end of the waveform generation module.
[0019] It should be noted that the frequency modulator may use a Sigma-Delta modulator (sigma-delta modulator or Σ-Δ modulator) to adjust the frequency.
[0020] Based on the above embodiments, in some modified implementations, the frequency modulator includes a first accumulator, a second accumulator, a delay device and an inverter connected in sequence; the output end of the divider is connected to the first accumulator, the second accumulator, the delay device and the inverter in sequence; the output end of the inverter is connected to the input end of the waveform generation module.
[0021] Based on the above embodiments, in some modified implementations, the waveform generation module includes a third accumulator and a search module; the output end of the delay device is connected to the input end of the third accumulator; the output end of the third accumulator is connected to the input end of the search module; and the output end of the search module is connected to the input end of the waveform output module.
[0022] Based on the above embodiments, in some modified implementations, the waveform output module includes a power supply and a waveform conversion chip, an operational amplifier, and a low-pass filter connected in sequence; the output end of the search module is connected to the waveform conversion chip, the operational amplifier, and the low-pass filter in sequence; the input end of the waveform conversion chip is also connected to the power pin of the power supply.
[0023] On the basis of the above embodiment, in some modified implementations, a host computer may be further included; the output end of the host computer is connected to the input end of the communication module; the host computer is used to send the required data of the waveform to be generated to the communication module, the required data including the target frequency, target phase, waveform type and working mode of the waveform generation module to be generated; a clock management module is used to generate a reference clock signal and send the reference clock signal to the communication module, the frequency adjustment module, the waveform generation module and the waveform output module respectively; the communication module is used to transmit the target frequency and the reference frequency of the reference clock signal to the frequency adjustment module, and the target phase, waveform type and working mode of the waveform generation module are respectively sent to the communication module, the frequency adjustment module, the waveform generation module and the waveform output module; , and working mode are transmitted to the waveform generation module; a frequency adjustment module is used to obtain a frequency adjustment coefficient based on the reference frequency and the first target frequency of the previous clock cycle every first clock cycle of the reference clock signal, and adjust the target frequency based on the frequency adjustment coefficient to obtain the second target frequency of the current clock cycle; the waveform generation module is used to generate a target waveform based on the second target frequency, target phase and waveform type every first clock cycle in the working mode, and transmit the target waveform to the waveform output module in the form of a digital signal; the waveform output module is used to output the target waveform in the form of an analog signal every first clock cycle.
[0024] It should be noted that the demand data may be data set by those skilled in the art according to actual needs, or data obtained by those skilled in the art after adjusting the set data according to actual needs.
[0025] Based on the above embodiments, in some modified implementations, a top-level control module may be included, which can be used to receive enable signals from each module and send enable signals to each module so that each module performs its corresponding operation based on the enable signal.
[0026] See also Figure 2Based on the above embodiments, in some modified implementations, the frequency adjustment module may include a divider and a frequency modulator; the divider is used to calculate the ratio of the reference frequency to the first target frequency every first clock cycle, and use the integer of the ratio as the first adjustment coefficient and the decimal as the second adjustment coefficient; the frequency modulator is used to adjust the target frequency based on the first adjustment coefficient and the second adjustment coefficient of the previous clock cycle every first clock cycle to obtain the second target frequency of the current clock cycle.
[0027] Furthermore, the divider may include a state machine and a register. The state machine may be used to control the divider IP core to multiplex the divider. The first adjustment coefficient and the second adjustment coefficient are calculated by repeatedly calling the divider, and the obtained output value is temporarily stored in the register.
[0028] Only one divider is provided in the frequency adjustment module, which can greatly reduce the overhead cost of hardware resources, thereby reducing the manufacturing cost of the radio frequency excitation source.
[0029] Based on the above embodiments, in some modified implementations, the frequency modulator includes a first accumulator, a second accumulator, a delayer, and an inverter connected in sequence; the first accumulator is used to accumulate the second adjustment coefficient with the first value of the previous clock cycle every first clock cycle to obtain the second value of the current clock cycle; the second accumulator is used to accumulate the second value with the third value of the previous clock cycle every first clock cycle to obtain a fourth value of the current cycle; the delayer is used to delay the fourth value by a preset second time period and then output it; the inverter is used to obtain the opposite of the delayed fourth value and output it; the frequency modulator is further used to use the sum of the first adjustment coefficient, the second value, and the fourth value as the third adjustment coefficient of the current clock cycle, and calculate the second target frequency of the current clock cycle based on the third adjustment coefficient and the first adjustment coefficient by the following formula:
[0030]
[0031] Among them, F e Indicates the second target frequency, F o represents the first target frequency, N represents the third adjustment coefficient, N o Indicates the first adjustment coefficient.
[0032] By dynamically adjusting the second adjustment coefficient of the frequency modulator in real time, the target frequency can be adjusted, which can significantly reduce the phase spurious generated by the RF excitation source when generating the target waveform, making the generated waveform closer to the ideal state, reducing signal distortion, and improving the overall signal quality.
[0033] Based on the above embodiments, in some modified implementations, the waveform generation module includes a third accumulator and a search module; the third accumulator is used to sum the second target frequency and target phase every first clock cycle to obtain a waveform index of the waveform to be generated; the search module is used to query the target waveform from a preset waveform lookup table based on the waveform index and waveform type every first clock cycle.
[0034] Based on the above embodiment, in some modified implementations, the third accumulator can use double-edge sampling. By using double-edge sampling, the data sampling rate is doubled without increasing the reference clock frequency, resulting in a significant improvement in the sampling rate. It can also achieve higher data throughput without increasing the clock frequency, helping to reduce the system's reliance on high-frequency clocks, thereby reducing clock-related design challenges and costs. It can also effectively reduce the system's overall power consumption. Because high-frequency clock signals lead to higher dynamic power consumption, reducing the clock frequency helps improve the system's energy efficiency.
[0035] Based on the above embodiment, in some modified implementations, the reference clock signal of the third accumulator can be frequency-multiplied by a PLL (Phase-Locked Loop) inside the FPGA to achieve a higher second target frequency synthesis output.
[0036] Based on the above embodiment, in some modified implementations, a white noise sequence may be introduced inside the third accumulator to further break up the second target frequency, thereby further reducing phase spurious.
[0037] It should be noted that the waveform lookup table can be different types of waveform data pre-set by those skilled in the art according to actual needs, or can be data obtained by adjusting the different types of waveform data already set according to actual needs. This embodiment of the present application is not specifically limited.
[0038] Furthermore, the waveform lookup table may use waveform compression technology to store data, that is, only storing waveform data of a half cycle of the desired signal, and utilizing the periodicity of the reference clock signal for replication, thereby obtaining higher phase resolution.
[0039] By using waveform compression technology to store data, the amount of memory required to store waveform data can be significantly reduced. In addition, compressed data takes up less storage space, which means that the data can be accessed faster when reading from storage media (such as RAM or Flash), which can significantly improve the speed and efficiency of waveform generation.
[0040] Furthermore, the waveform lookup table may include data such as waveform index, waveform type, waveform amplitude, etc. This embodiment of the present application does not specifically limit this.
[0041] Figure 3 The figure shows a comparison of the target waveforms generated by the RF excitation source provided by the embodiment of the present application and the RF excitation source of the prior art. Figure 3 As shown, the phase spur can be reduced by 10 dB in the process of generating the target waveform using the RF excitation source of the present application.
[0042] The RF excitation source of the embodiment of the present application includes: a clock management module, a communication module, a frequency adjustment module, a waveform generation module, and a waveform output module; the output end of the clock management module is respectively connected to the input ends of the communication module, the frequency adjustment module, the waveform generation module, and the waveform output module; the output end of the communication module is respectively connected to the input ends of the frequency adjustment module and the waveform generation module; the output end of the frequency adjustment module is connected to the input end of the waveform generation module; and the output end of the waveform generation module is connected to the input end of the waveform output module. By combining the frequency adjustment module with the waveform generation module, the present application can improve the phase spurious problem at a lower reference clock, while obtaining an excitation signal with higher frequency resolution and significantly reducing area power consumption.
[0043] An embodiment of the present application further provides a radio frequency system, which includes the radio frequency excitation source described in the above embodiment.
[0044] The radio frequency system provided in the embodiment of the present application and the radio frequency excitation source provided in the above embodiment are based on the same inventive concept and have the same beneficial effects as the methods adopted, operated or implemented therein.
[0045] Those skilled in the art will appreciate that although some embodiments described herein include certain features included in other embodiments but not other features, combinations of features from different embodiments are intended to be within the scope of this application and to form different embodiments. For example, in the claims below, any of the claimed embodiments may be used in any combination.
[0046] It should be noted that the above embodiments illustrate rather than limit the present application, and that a person skilled in the art may devise alternative embodiments without departing from the scope of the appended claims. In the claims, any reference symbols placed between brackets should not be construed as limiting the claims. The word "comprising" does not exclude the presence of elements or steps not listed in the claims. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The present application may be implemented by means of hardware comprising several different elements and by means of appropriately programmed computers. In a unit claim enumerating several means, several of these means may be embodied by the same item of hardware. The use of the words first, second, and third etc. does not indicate any order. These words may be interpreted as names.
[0047] The above description is merely a preferred embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.
Claims
1. A radio frequency excitation source, characterized in that: include: Clock management module, communication module, frequency adjustment module, waveform generation module and waveform output module; The output end of the clock management module is connected to the input ends of the communication module, the frequency adjustment module, the waveform generation module and the waveform output module respectively; The output end of the communication module is connected to the input end of the frequency adjustment module and the input end of the waveform generation module respectively; The output end of the frequency adjustment module is connected to the input end of the waveform generation module; The output end of the waveform generation module is connected to the input end of the waveform output module.
2. The radio frequency excitation source according to claim 1, characterized in that The frequency adjustment module includes a divider and a frequency modulator; The output end of the communication module is connected to the input end of the divider; The output end of the divider is connected to the input end of the frequency modulator; The output end of the frequency modulator is connected to the input end of the waveform generating module.
3. The radio frequency excitation source according to claim 2, characterized in that: The frequency modulator includes a first accumulator, a second accumulator, a delay device and an inverter connected in sequence; The output end of the divider is connected to the first accumulator, the second accumulator, the delay device and the inverter in sequence; The output end of the inverter is connected to the input end of the waveform generating module.
4. The radio frequency excitation source according to claim 3, characterized in that: The waveform generation module includes a third accumulator and a search module; The output end of the delay device is connected to the input end of the third accumulator; The output end of the third accumulator is connected to the input end of the search module; The output end of the search module is connected to the input end of the waveform output module.
5. The radio frequency excitation source according to claim 4, characterized in that: The waveform output module includes a power supply and a waveform conversion chip, an operational amplifier, and a low-pass filter connected in sequence; The output end of the search module is connected to the waveform conversion chip, the operational amplifier, and the low-pass filter in sequence; The input end of the waveform conversion chip is also connected to the power pin of the power supply.
6. The radio frequency excitation source according to any one of claims 1 to 5, characterized in that: Also includes a host computer; the output end of the host computer is connected to the input end of the communication module; The host computer is used to send the required data of the waveform to be generated to the communication module, wherein the required data includes the target frequency, target phase, waveform type of the waveform to be generated and the working mode of the waveform generation module; The clock management module is configured to generate a reference clock signal and send the reference clock signal to the communication module, the frequency adjustment module, the waveform generation module, and the waveform output module respectively; The communication module is configured to transmit the target frequency and the reference frequency of the reference clock signal to the frequency adjustment module, and transmit the target phase, the waveform type, and the operating mode to the waveform generation module; The frequency adjustment module is configured to obtain a frequency adjustment coefficient based on the reference frequency and the first target frequency of the previous clock cycle every first clock cycle of the reference clock signal, and adjust the target frequency based on the frequency adjustment coefficient to obtain a second target frequency of the current clock cycle; The waveform generation module is configured to generate a target waveform based on the second target frequency, the target phase, and the waveform type at every first clock cycle in the working mode, and transmit the target waveform to the waveform output module in the form of a digital signal; The waveform output module is used to output the target waveform in the form of an analog signal every first clock cycle.
7. The radio frequency excitation source according to claim 6, characterized in that: The frequency adjustment module includes a divider and a frequency modulator; The divider is configured to calculate a ratio of the reference frequency to the first target frequency every first clock cycle, and use an integer of the ratio as a first adjustment coefficient and a decimal as a second adjustment coefficient; The frequency modulator is configured to adjust the target frequency every first clock cycle based on the first adjustment coefficient and the second adjustment coefficient of the previous clock cycle to obtain the second target frequency of the current clock cycle.
8. The radio frequency excitation source according to claim 7, characterized in that: The frequency modulator includes a first accumulator, a second accumulator, a delay device and an inverter connected in sequence; The first accumulator is configured to accumulate the second adjustment coefficient and the first value of the previous clock cycle every first clock cycle to obtain the second value of the current clock cycle; the second accumulator is configured to accumulate the second value and the third value of the previous clock cycle every first clock cycle to obtain a fourth value of the current cycle; The delay device is used to output the fourth value after delaying it for a preset second time period; The inverter is used to obtain the opposite of the delayed fourth value and output it; The frequency modulator is further configured to use the sum of the first adjustment coefficient, the second value, and the fourth value as a third adjustment coefficient for the current clock cycle, and calculate a second target frequency for the current clock cycle based on the third adjustment coefficient and the first adjustment coefficient using the following formula: Among them, F e represents the second target frequency, F o represents the first target frequency, N represents the third adjustment coefficient, N o represents the first adjustment coefficient.
9. The radio frequency excitation source according to claim 6, characterized in that: The waveform generation module includes a third accumulator and a search module; The third accumulator is configured to sum the second target frequency and the target phase every first clock cycle to obtain a waveform index of the waveform to be generated; The search module is configured to search for the target waveform from a preset waveform search table based on the waveform index and the waveform type every first clock cycle.
10. A radio frequency system, characterized in that: The invention comprises the radio frequency excitation source according to any one of claims 1 to 9.