A microwave signal source with adjustable phase noise and spurious level
Patent Information
- Application Number
- CN202521845799.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-28
- Publication Date
- 2026-10-09
- Estimated Expiration
- 2035-08-28
AI Technical Summary
[0003]相位噪声是正弦波相位随机抖动程度的频域表现参数，通常采用不同相位噪声等级的晶振作为频率合成器参考信号来产生不同等级相位噪声的微波信号源，由于各类晶振相噪参数差异较大，无法实现相位噪声以较高的分辨率调控，对精确定量评估需求失去意义
[0010]本实用新型的有益效果在于：本实用新型所提出的信号源通过锁相环电路产生频率可控的信号源，并通过数控衰减器控制信号源的输出功率。将该信号源通过耦合器耦合到载波信号中形成频率及功率均可灵活控制杂散信号，以适应多场景应用需求；本实用新型中相位可补偿的微带多路功分器，可在相位敏感的本振信号处进行相位补偿，从而实现通道的相位一致性目的，本方法无需额外器件开销，补偿电路与功分网络均设计在印制电路板中，结构简单而且几乎不会引人额外差损耗，相位补偿量可根据测试结果精确补偿，无需复杂相位补偿算法。
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Abstract
Description
Technical Field
[0001] This utility model relates to the field of microwave system testing and evaluation technology, such as communication, radar, and electronic countermeasures, and in particular to a microwave signal source with adjustable phase noise and spurious level. Background Technology
[0002] Microwave signal sources are core units in microwave systems such as microwave communication, radar systems, and electronic countermeasures, playing a crucial role in determining the performance of these systems. Phase noise and spurious levels are key indicators of microwave signal sources, directly affecting technical and tactical indicators such as microwave communication bit error rate, radar clutter visibility, radar false alarm rate, and target or threat detection success rate. Therefore, quantitatively assessing the impact of microwave signal source phase noise and spurious levels on microwave systems is of great significance. On the one hand, it allows for accurate evaluation of system performance under different levels of phase noise and spurious levels, clarifying the associated system parameters, and thus providing threshold indicators for each microwave subsystem based on measured data. On the other hand, it allows for the improvement and optimization of signal processing algorithms under different levels of phase noise and spurious levels, enhancing overall system performance and accurately evaluating the degree of performance improvement. Therefore, precise controllability of microwave signal source phase noise and spurious levels is fundamental to achieving the above objectives.
[0003] Phase noise is a frequency domain parameter representing the degree of random phase jitter in a sinusoidal wave. Typically, crystal oscillators with different phase noise levels are used as reference signals for frequency synthesizers to generate microwave signal sources with varying phase noise levels. However, due to the significant differences in phase noise parameters among various crystal oscillators, it is impossible to achieve high-resolution control of phase noise, rendering it meaningless for precise quantitative assessment. Furthermore, signal sources based on crystal oscillators with multiple phase noise levels suffer from disadvantages in terms of size, power consumption, and cost. Utility Model Content
[0004] To address the aforementioned technical problems, this invention provides a microwave signal source with adjustable phase noise and spurious levels. Based on a single crystal oscillator, a phase noise control circuit links the adjustment of phase noise to the control of the attenuation of the reference signal. This ensures that the control accuracy and adjustment range of the microwave signal source's phase noise are at the same level as the attenuation accuracy and range of a digitally controlled attenuator. This design not only simplifies the circuit architecture but also significantly improves the resolution of phase noise control, making quantitative assessment based on phase noise feasible.
[0005] This utility model is achieved using the following technical solution: A microwave signal source with adjustable phase noise and spurious level includes a power divider, a phase noise control circuit, a main phase-locked loop circuit, a coupler, and a low-pass filter 2 connected sequentially from a temperature-controlled crystal oscillator to the output terminal of the microwave signal source, and also includes a spurious level control circuit.
[0006] Specifically, the power divider includes two branches, one of which is connected to the phase noise control circuit, and the other is connected to the reference input terminal of the spurious level control circuit. The output terminal of the spurious level control circuit is connected to the coupling port of the coupler.
[0007] Specifically, the phase noise control circuit includes a symmetrically arranged single-pole double-throw switch 1 and a single-pole double-throw switch 2. Each of the single-pole double-throw switches 1 and 2 includes two branches. Branch 1 of the single-pole double-throw switch 1 is connected to branch 2 of the single-pole double-throw switch 2 to form channel one, and branch 2 of the single-pole double-throw switch 1 is connected to branch 1 of the single-pole double-throw switch 2 to form channel two.
[0008] Specifically, the second channel is also connected in sequence to a digitally controlled attenuator 1, a digitally controlled attenuator 2, a low-noise amplifier, and a variable gain amplifier.
[0009] Specifically, the spurious level control circuit includes a spurious generation phase-locked loop, a digitally controlled attenuator 3, a digitally controlled attenuator 4, and a low-pass filter 1 connected in sequence; the output terminal of the low-pass filter 1 is connected to the coupling port of the coupler.
[0010] The beneficial effects of this invention are as follows: The signal source proposed in this invention generates a frequency-controllable signal source through a phase-locked loop circuit, and the output power of the signal source is controlled by a digitally controlled attenuator. This signal source is coupled to a carrier signal via a coupler to form a spurious signal whose frequency and power can be flexibly controlled to adapt to the needs of various application scenarios. The phase-compensated microstrip power divider in this invention can perform phase compensation at the phase-sensitive local oscillator signal, thereby achieving the phase consistency of the channel. This method requires no additional component overhead; the compensation circuit and power divider network are designed in a printed circuit board, resulting in a simple structure that introduces almost no additional differential loss. The phase compensation amount can be accurately compensated based on test results, eliminating the need for complex phase compensation algorithms.
[0011] This utility model solves the problem of precise and controllable phase noise index of microwave signal source. The phase noise control accuracy is at the same level as that of digitally controlled attenuator, with a typical value of 0.5dB. It also solves the problem of wide-range control of phase noise index of microwave signal source, with a phase noise control range of 31.5dB. Furthermore, it solves the problem of controllable frequency deviation of microwave signal source spurious signals, with a frequency resolution of <1Hz. Finally, it solves the problem of controllable spurious level of microwave signal source, with a spurious level control range of 63dB and a spurious level control step of 0.5dB. Attached Figure Description
[0012] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.
[0013] Figure 1 This is a circuit diagram of a microwave signal source with adjustable phase noise and spurious level in an embodiment of this utility model. Detailed Implementation
[0014] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.
[0015] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.
[0016] The following is in conjunction with the appendix Figure 1 The following describes some embodiments of the present invention in detail. Unless otherwise specified, the following embodiments and features can be combined with each other.
[0017] This invention proposes a microwave signal source with adjustable phase noise and spurious levels. In a preferred embodiment, such as... Figure 1 As shown, the microwave signal source consists of a temperature-controlled crystal oscillator, a power divider, a phase noise control circuit, a spurious level control circuit, a main phase-locked loop circuit, a coupler, and a low-pass filter 2. The phase noise control circuit comprises a single-pole double-throw switch 1, a single-pole double-throw switch 2, a digitally controlled attenuator 1, a digitally controlled attenuator 2, a low-noise amplifier, and a variable gain amplifier. The spurious level control circuit comprises a spurious generation phase-locked loop, a digitally controlled attenuator 3, a digitally controlled attenuator 4, and a low-pass filter 2.
[0018] In this embodiment, the low phase noise reference signal output from the temperature-controlled crystal oscillator is divided into two paths by a power divider. One path is output to the phase noise control circuit, and the other path is output to the reference input of the spurious level generation phase-locked loop (PLL) circuit. The phase noise control circuit outputs to the reference port of the main PLL, which generates the required microwave signal source, which is then output via a coupler and a low-pass filter. The spurious level control circuit outputs to the coupling port of the coupler.
[0019] The phase noise control circuit is configured as follows: the signal input from the two power dividers is fed to the common port of single-pole double-throw switch 1, and one branch 1 of single-pole double-throw switch 1 is directly connected to branch 2 of single-pole double-throw switch 2. Branch 2 of single-pole double-throw switch 1 is connected to branch 1 of single-pole double-throw switch 2 after passing through digitally controlled attenuator 1, digitally controlled attenuator 2, low-noise amplifier, and variable gain amplifier.
[0020] The spurious level control circuit is configured as follows: the RF output terminal of the spurious generation phase-locked loop is connected to the input terminal of the digitally controlled attenuator 3; the output terminal of the digitally controlled attenuator 3 is connected to the input terminal of the digitally controlled attenuator 4; the output terminal of the digitally controlled attenuator 4 is connected to the input terminal of the low-pass filter 1; and the output terminal of the low-pass filter is connected to the coupling port of the coupler.
[0021] The following is a detailed explanation of the control mechanism of this microwave signal source with adjustable phase noise and spurious levels: (1) Phase noise modulation mechanism: When the microwave signal source is in its optimal phase noise setting, the single-pole double-throw switch is switched to the direct-on position, i.e., channel one. When it is necessary to adjust the phase noise value, the single-pole double-throw switch is switched to channel two, controlling the attenuation IL1 of the digitally controlled attenuator 1 to be close to the gain G1 of the low-noise amplifier. Simultaneously, the attenuation IL2 of the digitally controlled attenuator 2 is controlled to be approximately equal to the gain G2 of the variable-gain amplifier. At this point, the increase in phase noise corresponds to the increase in IL2 and G2. Therefore, by simply changing IL2 and the corresponding G2 value, the phase noise value can be precisely adjusted.
[0022] Among them, the attenuation range of the numerically controlled attenuator 1 is 31.5dB, with an attenuation step of 0.5dB; the attenuation range of the numerically controlled attenuator 2 is 31.5dB, with an attenuation step of 0.5dB; the gain of the low-noise amplifier is 25dB; the gain range of the variable gain amplifier is 0dB~31.5dB, with a gain step of 0.5dB.
[0023] (2) Spurious level control mechanism: The stray signal generation phase-locked loop generates a microwave signal that deviates from the main phase-locked loop at a certain frequency. The frequency offset value can be precisely set according to the application requirements. By controlling the attenuation of digitally controlled attenuators 3 and 4, the output stray signal level can be precisely controlled. This achieves precise control over the stray frequency offset and the magnitude of the stray signal level.
[0024] Among them, the attenuation range of the CNC attenuator 3 is 31.5dB, and the attenuation step is 0.5dB; the attenuation range of the CNC attenuator 4 is 31.5dB, and the attenuation step is 0.5dB.
[0025] The microwave signal source proposed in this invention is based on a crystal oscillator. Through a phase noise modulation circuit, the modulation of phase noise is correlated with the control of the attenuation of the reference signal, so that the control accuracy and modulation range of the microwave signal source's phase noise are at the same level as the attenuation accuracy and attenuation range of a digitally controlled attenuator. This design not only simplifies the circuit architecture but also greatly improves the resolution of phase noise control, making quantitative evaluation based on phase noise feasible.
[0026] A microwave signal source generates a frequency-controllable signal through a phase-locked loop circuit, and the output power of the signal source is controlled by a digitally controlled attenuator. This signal source is then coupled to a carrier signal via a coupler to form spurious signals whose frequency and power can be flexibly controlled to meet the needs of various application scenarios.
[0027] For the foregoing embodiments, in order to simplify the description, they are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, because according to this application, some steps can be performed in other orders or simultaneously. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions involved are not necessarily essential to this application.
[0028] The above embodiments describe the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this utility model. Modifications and variations made by those skilled in the art without departing from the spirit and scope of this utility model should be protected within the scope of the appended claims.
Claims
1. A microwave signal source with adjustable phase noise and spurious level, characterized in that, It includes a power divider, a phase noise control circuit, a main phase-locked loop circuit, a coupler, and a low-pass filter 2, which are connected in sequence from the temperature-controlled crystal oscillator to the output of the microwave signal source. It also includes a spurious level control circuit.
2. A microwave signal source with adjustable phase noise and spurious levels as described in claim 1, characterized in that, The power divider includes two branches, one of which is connected to the phase noise control circuit, and the other is connected to the reference input terminal of the spurious level control circuit. The output terminal of the spurious level control circuit is connected to the coupling port of the coupler.
3. A microwave signal source with adjustable phase noise and spurious levels as described in claim 1, characterized in that, The phase noise control circuit includes a symmetrically arranged single-pole double-throw switch 1 and a single-pole double-throw switch 2. Each single-pole double-throw switch 1 and single-pole double-throw switch 2 includes two branches. Branch 1 of single-pole double-throw switch 1 is connected to branch 2 of single-pole double-throw switch 2 to form channel one, and branch 2 of single-pole double-throw switch 1 is connected to branch 1 of single-pole double-throw switch 2 to form channel two.
4. A microwave signal source with adjustable phase noise and spurious levels as described in claim 3, characterized in that, Channel 2 is also connected in sequence to digitally controlled attenuator 1, digitally controlled attenuator 2, low-noise amplifier and gain variable amplifier.
5. A microwave signal source with adjustable phase noise and spurious levels as described in claim 1, characterized in that, The spurious level control circuit includes a spurious generation phase-locked loop, a digitally controlled attenuator 3, a digitally controlled attenuator 4, and a low-pass filter 1 connected in sequence; the output terminal of the low-pass filter 1 is connected to the coupling port of the coupler.