A frequency synthesizer

Abstract

This utility model relates to the field of communication technology, specifically disclosing a frequency synthesizer, including a power divider. The input terminal of the power divider receives a reference signal, and the output terminal of the power divider is connected to the input terminals of an integrated phase-locked loop (PLL) A and an amplification and filtering circuit. The output terminal of the integrated PLL A is connected to the input terminal of a low-pass filter, and the output terminal of the low-pass filter is connected to the input terminal of a mixer. The output terminal of the amplification and filtering circuit is connected to the input terminal of the mixer. The output terminal of the mixer is connected to the input terminal of a filtering circuit, and the output terminal of the filtering circuit is connected to the input terminal of an integrated PLL B. The output terminal of the integrated PLL B is connected to the input terminal of a multi-path output circuit, and the output terminal of the multi-path output circuit outputs a signal. This utility model device has stable performance, is easy to implement, low in cost, small in size, and highly reliable, and can be widely used in measurement systems, communications, and other fields.

Description

Technical Field

[0001] This utility model relates to the field of communication technology, and more specifically to a frequency synthesizer. Background Technology

[0002] With the rapid development of modern communication technologies, microwave and millimeter-wave test instruments have become core tools for verifying the performance of 5G / 6G equipment. Common examples include vector signal generators, spectrum analyzers, vector network analyzers, and channel simulators. Among these communication measurement instruments, the performance of the frequency synthesizer has a significant impact on the test instrument, directly affecting the accuracy and reliability of the test results. As communication frequency bands expand to higher frequencies, traditional frequency synthesis techniques face numerous challenges, such as the degradation of phase noise in high-frequency bands, the complexity of wideband coverage, and the need for miniaturization and low cost. Therefore, researching wideband, low phase noise, high resolution, small size, low cost, and low spurious emission frequency synthesis methods is particularly important. Utility Model Content

[0003] The purpose of this invention is to provide a frequency synthesizer with excellent key technical indicators such as stability, low cost, high reliability, wide bandwidth, low phase noise, and low spurious emissions, in order to solve the problems mentioned in the background art.

[0004] To achieve the above objectives, this utility model provides a frequency synthesizer, comprising:

[0005] A power divider receives a reference signal at its input and its output is connected to the input of an integrated phase-locked loop (PLL) A and the input of an amplification and filtering circuit. The PLL A generates a small-step reference signal with low spurious emissions. The amplification and filtering circuit outputs a local oscillator signal with low phase noise.

[0006] The output of the integrated phase-locked loop is connected to the input of the low-pass filter, and the output of the low-pass filter is connected to the input of the mixer; the output of the amplification and filtering circuit is connected to the input of the mixer; the mixer mixes the frequencies of the two input signals and outputs a continuously variable low-noise spurious reference signal.

[0007] The output of the mixer is connected to the input of the filter circuit, which removes spurious signals from the mixer output, retaining only the target frequency band input to the phase-locked loop (PLL) B. The output of the filter circuit is also connected to the input of the integrated PLL B, which uses the mixed signal as a reference to generate a higher frequency and more stable radio frequency signal. The output of the integrated PLL B is connected to the input of a multi-path output circuit, which ultimately outputs a wide-bandwidth, small-step, low-phase-noise, and low-spurious-signal signal with selectable multi-frequency bands.

[0008] Preferably, the multipath output circuit includes a frequency multiplier circuit and an amplifier D; the input terminal of the frequency multiplier circuit is connected to the output terminal of a 2-to-1 RF switch A, and the output terminal of the frequency multiplier circuit is connected to the input terminal of a 4-to-1 RF switch; the input terminal of the amplifier D is connected to the output terminal of the 2-to-1 RF switch A, and the output terminal is connected to the input terminal of the 4-to-1 RF switch.

[0009] Preferably, the frequency multiplier circuit includes a frequency multiplier, a ceramic filter A, and a ceramic filter B; the input terminal of the frequency multiplier is connected to the output terminal of a 2-to-1 RF switch A, and the output terminal is connected to the input terminal of a 2-to-1 RF switch B; the ceramic filters A and B are connected in parallel, with their input terminals connected to the output terminal of the 2-to-1 RF switch B, and their output terminals connected to the input terminal of a 4-to-1 RF switch. The frequency multiplier circuit amplifies the RF signal and performs segmented filtering of the RF signal through the ceramic filters A and B.

[0010] Preferably, both ceramic filter A and ceramic filter B include a dielectric substrate, with connecting lines at both ends of one surface of the dielectric substrate, and multiple resonant cavities between the two connecting lines. The purpose of providing connecting lines is to match the 50-ohm output port.

[0011] Preferably, the resonant cavity of the ceramic filter A includes a perforated resonant cavity and a non-perforated resonant cavity; the non-perforated resonant cavity has an L-shaped gold-plated surface layer; the perforated resonant cavity includes a T-shaped resonant cavity, an L-shaped resonant cavity, and a rectangular resonant cavity, and the perforated resonant cavity is composed of a gold-plated surface layer and a grounding via disposed on the gold-plated surface layer; the ceramic filter A is symmetrical about the rectangular resonant cavity as an axis of symmetry; resonant cavity groups are provided on both sides of the rectangular resonant cavity, and a non-perforated resonant cavity is provided on the other side of the resonant cavity group, and the non-perforated resonant cavity is connected to the connecting line.

[0012] Preferably, the resonant cavity group includes a T-shaped resonant cavity and an L-shaped resonant cavity; the T-shaped resonant cavity has an L-shaped resonant cavity on one side of its vertical structure and a vertically opposite T-shaped resonant cavity on the other side; the short side of the L-shaped resonant cavity is provided with a grounding via; the T-shaped resonant cavity has a grounding via on its transverse structure.

[0013] Preferably, the resonant cavity of the ceramic filter B is a rectangular resonant cavity; one end of the rectangular resonant cavity is provided with a grounding via, and the rectangular resonant cavities are distributed in parallel on the dielectric substrate; the grounding vias on every two rectangular resonant cavities are staggered. Changing the parameters of the resonant cavity enables the ceramic filter to achieve the filtering effect on signals of a specific frequency.

[0014] Preferably, in the multi-path output circuit, the amplifier D and the frequency multiplier circuit are selected by a two-to-one RF switch A, and finally a wide-bandwidth, small-step, low-spurious signal with multiple frequency bands is output.

[0015] Preferably, the amplification and filtering circuit includes an amplifier A, a harmonic generator, a surface acoustic wave filter A, and an amplifier B connected in series.

[0016] Preferably, the filtering circuit includes a surface acoustic wave (SAW) filter B, an amplifier C, and a SAW filter C connected in series.

[0017] Preferably, the integrated phase-locked loop B is model ADF4368BCCZ. The integrated phase-locked loop B can generate a higher frequency and more stable signal from the mixed and filtered signal, and can also extend the frequency range through its internal VCO and frequency divider.

[0018] Compared with the prior art, the embodiments of this utility model have at least the following advantages or beneficial effects:

[0019] Compared with previous technologies, the frequency synthesizer of this invention can provide a signal with the same accuracy and stability as the reference signal, making it suitable for applications requiring a high-precision frequency source. The frequency synthesizer can quickly lock the input signal and achieve rapid frequency switching. The frequency synthesizer can provide a low phase noise output signal, which is crucial to the performance of the communication system. It adopts a relatively simple and cost-effective solution, with low cost and small size. Some aspects will be understood by those skilled in the art through research and practice of this invention. The product of this invention has good consistency, requires little debugging, has low production cost, and high reliability, and can be widely used in communication, test and measurement, electronic reconnaissance, instrumentation and other fields. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the principle of this utility model;

[0021] Figure 2 This is a schematic diagram of the structure of the ceramic filter B of this utility model;

[0022] Figure 3 This is a schematic diagram of the structure of the ceramic filter A of this utility model.

[0023] As shown in the figure:

[0024] 1-Amplification and filtering circuit, 2-Filtering circuit, 3-Multi-path output circuit, 4-Frequency multiplier circuit, 5-Surface gold plating layer, 6-Grounding via, 7-Rectangular resonant cavity, 8-Dielectric substrate, 9-T-type resonant cavity, 10-L-type resonant cavity, 11-Connecting line, 12-Non-hole resonant cavity. Detailed Implementation

[0025] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the protection scope of the present utility model.

[0026] Reference Figure 1 As shown, this utility model provides a frequency synthesizer:

[0027] The system includes a power divider, whose input receives a reference signal, and whose output is connected to the input of an integrated phase-locked loop A and the input of an amplification and filtering circuit 1, respectively. The power divider is model SBTC-2-10+. The integrated phase-locked loop A is model LMX2572RHAR, which has the advantage of being able to generate a continuously variable reference signal with low phase noise and low spurious emissions. The power divider used is model SBTC-2-10+.

[0028] The output of the integrated phase-locked loop A is connected to the input of the low-pass filter, and the output of the low-pass filter is connected to the input of the mixer; the output of the amplification and filtering circuit 1 is connected to the input of the mixer; the mixer is model ADE-35MH+, which has the advantages of passive double balance, high P-1, and low spurious components. The low-pass filter is a self-made low-pass filter.

[0029] The output of the mixer is connected to the input of the filter circuit 2, the output of the filter circuit 2 is connected to the input of the integrated phase-locked loop B, and the output of the integrated phase-locked loop B is connected to the input of the multi-path output circuit 3. The multi-path output circuit 3 outputs a signal. The integrated phase-locked loop B is model ADF4368BCCZ, and its advantages include good bottom noise, low phase discrimination spurious emissions, and small size.

[0030] In one specific embodiment, the multipath output circuit 3 includes a frequency multiplier circuit 4 and an amplifier D; the input terminal of the frequency multiplier circuit 4 is connected to the output terminal of a 2-to-1 RF switch A, and the output terminal of the frequency multiplier circuit 4 is connected to the input terminal of a 4-to-1 RF switch; the input terminal of the amplifier D is connected to the output terminal of the 2-to-1 RF switch A, and the output terminal is connected to the input terminal of the 4-to-1 RF switch. The frequency multiplier circuit 4 includes a frequency multiplier, a ceramic filter A, and a ceramic filter B; the input terminal of the frequency multiplier is connected to the output terminal of the 2-to-1 RF switch A, and the output terminal is connected to the input terminal of the 2-to-1 RF switch B; the ceramic filters A and B are connected in parallel, and their input terminals are connected to the output terminal of the 2-to-1 RF switch B, and their output terminals are connected to the input terminal of the 4-to-1 RF switch.

[0031] Furthermore, both the two-to-one RF switch A and the two-to-one RF switch B are model ARW3271, which has the advantages of low insertion loss and high isolation. The four-to-one RF switch is model ARW3472. The ceramic filter A and the ceramic filter B are self-made filters with good filtering characteristics. The frequency multiplier is a broadband frequency multiplier with low phase noise, low input power, and high output power.

[0032] In a specific scenario, both ceramic filter A and ceramic filter B include a dielectric substrate 8, with connecting lines 11 at both ends of the dielectric substrate 8, and multiple resonant cavities between the two connecting lines 11.

[0033] Furthermore, the resonant cavity of the ceramic filter A includes a perforated resonant cavity and a non-perforated resonant cavity 12; the non-perforated resonant cavity is an L-shaped surface gold-plated layer 5; the perforated resonant cavity includes a T-shaped resonant cavity 9, an L-shaped resonant cavity 10, and a rectangular resonant cavity 7, and the perforated resonant cavity is composed of a surface gold-plated layer 5 and a grounding via 6 disposed on the surface gold-plated layer 5; the ceramic filter A is symmetrical about the rectangular resonant cavity 7 as an axis of symmetry; resonant cavity groups are provided on both sides of the rectangular resonant cavity 7, and a non-perforated resonant cavity 12 is provided on the other side of the resonant cavity group, and the non-perforated resonant cavity 12 is connected to the connecting line 11.

[0034] The resonant cavity group includes a T-shaped resonant cavity 9 and an L-shaped resonant cavity 10; the vertical structure of the T-shaped resonant cavity 9 has an L-shaped resonant cavity 10 on one side and a vertically opposite T-shaped resonant cavity 9 on the other side; the part of the L-shaped resonant cavity 10 perpendicular to the T-shaped resonant cavity 9 has a grounding via 6; the horizontal structure of the T-shaped resonant cavity 9 has a grounding via 6.

[0035] Furthermore, the resonant cavity of the ceramic filter B is a rectangular resonant cavity 7; one end of the rectangular resonant cavity 7 is provided with a grounding via 6, and the rectangular resonant cavities 7 are distributed in parallel on the dielectric substrate 8; the grounding vias 6 on every two rectangular resonant cavities 7 are staggered.

[0036] The dielectric substrate 8 is made of alumina ceramic, which has excellent electrical insulation properties. The ceramic filter A has a filtering frequency of 15-20 Hz. The ceramic filter B has nine rectangular resonant cavities and a filtering frequency of 12-15 Hz.

[0037] In one specific embodiment, the filter circuit 2 includes a surface acoustic wave (SAW) filter B, an amplifier C, and a SAW filter C connected in series.

[0038] In one specific embodiment, the amplification and filtering circuit 1 includes an amplifier A, a harmonic generator, a surface acoustic wave filter A, and an amplifier B connected in series.

[0039] Finally, amplifiers A, B, C, and D are of model HMC589AST89ETR, which has the advantage of low phase noise; the harmonic generator is model SMMD840-SOD323, which has the advantage of generating a low phase noise local oscillator signal in this circuit. Surface acoustic wave (SAW) filters A, B, and C are of model TA0536A.

[0040] The above description is merely an example and illustration of the structure of this utility model. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the structure of the invention or exceed the scope defined in the claims, they should all fall within the protection scope of this utility model.

Claims

1. A frequency synthesizer, characterized in that, Includes a power divider, the input of which receives a reference signal, and the output of which is connected to the input of the integrated phase-locked loop A and the amplification and filtering circuit (1), respectively; The output of the integrated phase-locked loop A is connected to the input of the low-pass filter, and the output of the low-pass filter is connected to the input of the mixer; the output of the amplification and filtering circuit (1) is connected to the input of the mixer. The output terminal of the mixer is connected to the input terminal of the filter circuit (2), the output terminal of the filter circuit (2) is connected to the input terminal of the integrated phase-locked loop B, the output terminal of the integrated phase-locked loop B is connected to the input terminal of the multi-path output circuit (3), and the output terminal of the multi-path output circuit (3) outputs a signal.

2. A frequency synthesizer according to claim 1, characterized in that, The multipath output circuit (3) includes a frequency multiplier circuit (4) and an amplifier D; the input terminal of the frequency multiplier circuit (4) is connected to the output terminal of the two-to-one RF switch A, and the output terminal of the frequency multiplier circuit (4) is connected to the input terminal of the four-to-one RF switch; the input terminal of the amplifier D is connected to the output terminal of the two-to-one RF switch A, and the output terminal is connected to the input terminal of the four-to-one RF switch.

3. A frequency synthesizer according to claim 2, characterized in that, The frequency multiplier circuit (4) includes a frequency multiplier, a ceramic filter A and a ceramic filter B; the input terminal of the frequency multiplier is connected to the output terminal of the two-to-one RF switch A, and the output terminal is connected to the input terminal of the two-to-one RF switch B; the ceramic filter A and the ceramic filter B are connected in parallel, and their input terminals are connected to the output terminal of the two-to-one RF switch B, and their output terminals are connected to the input terminal of the four-to-one RF switch.

4. A frequency synthesizer according to claim 3, characterized in that, Both ceramic filter A and ceramic filter B include a dielectric substrate (8), and connecting lines (11) are respectively provided at both ends of one surface of the dielectric substrate (8), and multiple resonant cavities are provided between the two connecting lines (11).

5. A frequency synthesizer according to claim 4, characterized in that, The resonant cavity of the ceramic filter A includes a perforated resonant cavity and a non-perforated resonant cavity (12); the non-perforated resonant cavity (12) is an L-shaped surface gold-plated layer (5); the perforated resonant cavity includes a T-shaped resonant cavity (9), an L-shaped resonant cavity (10), and a rectangular resonant cavity (7). The perforated resonant cavity is composed of a surface gold-plated layer (5) and a grounding via (6) disposed on the surface gold-plated layer (5); the ceramic filter A is symmetrical about the rectangular resonant cavity (7) as the axis of symmetry; resonant cavity groups are provided on both sides of the rectangular resonant cavity (7), and a non-perforated resonant cavity (12) is provided on the other side of the resonant cavity group. The non-perforated resonant cavity (12) is connected to the connecting line (11).

6. A frequency synthesizer according to claim 5, characterized in that, The resonant cavity group includes a T-shaped resonant cavity (9) and an L-shaped resonant cavity (10); the T-shaped resonant cavity (9) has an L-shaped resonant cavity (10) on one side of its vertical structure and a vertically opposite T-shaped resonant cavity (9) on the other side; the short side of the L-shaped resonant cavity (10) is provided with a grounding via (6); the transverse structure of the T-shaped resonant cavity (9) is provided with a grounding via (6).

7. A frequency synthesizer according to claim 4, characterized in that, The resonant cavity of the ceramic filter B is a rectangular resonant cavity (7); one end of the rectangular resonant cavity (7) is provided with a grounding via (6), and the rectangular resonant cavities (7) are distributed in parallel on the dielectric substrate (8); the grounding vias (6) on every two rectangular resonant cavities (7) are staggered.

8. A frequency synthesizer according to claim 1, characterized in that, The amplification and filtering circuit (1) includes an amplifier A, a harmonic generator, a surface acoustic wave filter A, and an amplifier B connected in series.

9. A frequency synthesizer according to claim 1, characterized in that, The filtering circuit (2) includes a series-connected surface acoustic wave (SAW) filter B, an amplifier C, and a SAW filter C.

10. A frequency synthesizer according to claim 1, characterized in that, The integrated phase-locked loop B is model ADF4368BCCZ.

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