Frequency source

Abstract

The utility model relates to the technical field of communication systems, and discloses a frequency source, which comprises a harmonic generator, a first filter, a first amplifier, a second filter, a second amplifier, a third filter, a detector, a comparator and a power supply module, the output end of the harmonic generator sequentially passes through a first filter, a first amplifier, a second filter, a second amplifier and a third filter, the output end of the third filter is divided into two paths, one path is output to an external load to form an output signal, and the other path is subjected to power coupling and then sequentially passes through a detector and a comparator to output a high level; the frequency source can reduce the power consumption of products, reduce the types of components, and improve the utilization rate of printed boards and installation space.

Description

Technical Field

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

[0002] Frequency sources are one of the key components of communication systems. Their main function is to provide carrier signals for the channel. With the development of aerospace technology, modern high-performance communication equipment has placed higher demands on the performance of frequency sources.

[0003] Currently, most frequency sources in communication components adopt a design that combines multi-cavity partitioned board-level circuits with metal enclosures. This design consists of control circuits and phase-locked loop circuits. Although it has a mature application background and can meet the requirements of interference suppression to the greatest extent, the multi-cavity partitioning reduces space utilization. To ensure reliable installation and fixation, the printed circuit board needs to have screw mounting holes for fixing to the structure. To reduce crosstalk between signals within the component and between spatial signals, screw mounting holes for the structure cover also need to be provided. In addition, this design requires the use of various control circuits, resulting in a large variety and number of components. Besides the complexity of the solution, it also increases the risk of program and functional circuit failure.

[0004] Another frequency source design scheme employs a double-sided PCB layout, with components arranged on both sides. The bottom center of the structure is removed, resulting in a hollow interior. The printed circuit board (PCB) is directly mounted on mounting holes along the internal edge of the structure. While this design improves board space utilization and reduces product size, it places higher demands on the layout within limited space. This leads to a significant increase in machining waste and machining difficulty, increasing material costs. The limited contact area between the PCB and the structure, coupled with limited grounding measures, hinders optimal circuit functionality. Machining precision issues prevent guaranteeing gaps between the PCB and the structure, weakening the physical structure's ability to suppress spatial interference and increasing debugging workload. Utility Model Content

[0005] The purpose of this invention is to at least solve one of the technical problems existing in the prior art by providing a frequency source that can reduce product power consumption, reduce the types of components, and improve the utilization rate of printed circuit boards and installation space.

[0006] To achieve the above objectives, this utility model provides a frequency source, comprising:

[0007] The harmonic generator has its input terminal connected to the reference input signal.

[0008] The first filter has its input terminal connected to the output terminal of the harmonic generator;

[0009] The input terminal of the first amplifier is connected to the output terminal of the first filter;

[0010] The second filter has its input terminal connected to the output terminal of the first amplifier.

[0011] The input terminal of the second amplifier is connected to the output terminal of the second filter;

[0012] The third filter has its input terminal connected to the output terminal of the second amplifier. The output terminal of the third filter includes a first output terminal and a second output terminal. The first output terminal of the third filter is connected to an external load.

[0013] The detector's input is connected to the second output of the third filter.

[0014] The comparator's input is connected to the output of the detector;

[0015] The power supply module is electrically connected to the harmonic generator, the first amplifier, the second amplifier, the detector, and the comparator, respectively.

[0016] Optionally, the first filter, the second filter, and the third filter are all surface acoustic wave filters.

[0017] Optionally, the device further includes a housing and a PCB, the PCB being disposed on the inner bottom side of the housing, and the harmonic generator, the first filter, the first amplifier, the second filter, the third filter, the detector, the comparator, and the power module being disposed on the PCB away from the top side of the housing.

[0018] Optionally, the harmonic generator is located at the upper left corner of the PCB, the first filter is located to the right of the harmonic generator, the first amplifier is located to the right of the first filter, the second filter is located below the first filter, the second amplifier is located below the second filter, the third filter is located to the lower right of the second amplifier, the detector is located below the third filter, the comparator is located to the lower left of the second amplifier, and the power supply module is located at the lower left corner of the PCB.

[0019] Optionally, the PCB layout structure adopts a four-layer board structure.

[0020] Optionally, the distance between the copper plating area of ​​the PCB and the boundary of the PCB is set to 0.15mm.

[0021] Optionally, the distance between the lower boundary of the PCB and the inner wall of the housing is 0.5 mm, and the distance between the upper boundary, left boundary and right boundary of the PCB and the inner wall of the housing is 0.2 mm.

[0022] Optionally, the bottom surface of the PCB is configured with a full-surface solder mask window.

[0023] Optionally, the edge of the PCB is provided with pad clearance grooves that match the shape of the insulator leads on the housing.

[0024] Optionally, the surface of the housing is provided with a gold layer, the thickness of the gold layer is greater than 1.5 μm, and the wall thickness of the side plate of the housing is 0.75 mm.

[0025] Through the above technical solution, this utility model provides a frequency source in which the reference input signal sequentially passes through a harmonic generator, a first filter, a first amplifier, a second filter, a second amplifier, and a third filter for multi-stage filtering and amplification. This ensures that the output signal meets specific spectral requirements and suppresses distortion. Simultaneously, a portion of the signal is coupled to a detector for demodulation. A comparator extracts the useful signal and compares the detected signal with a preset threshold, outputting a high-level signal to trigger subsequent logic or control. A power supply module provides a stable power supply to the harmonic generator, amplifier, detector, and comparator, ensuring normal circuit operation. By employing frequency multiplication of the reference signal and extracting its specific harmonic components for multi-stage amplification and filtering, the number of components is reduced, and product power consumption is lowered, thereby effectively improving the reliability and space utilization of the design. Attached Figure Description

[0026] Figure 1 This is a block diagram of a frequency source provided by this utility model;

[0027] Figure 2 This is a layout diagram of the main components of a frequency source on a PCB provided by this utility model;

[0028] Figure 3 This is a schematic diagram of the assembly of the housing and the PCBA in this utility model;

[0029] Figure 4 This is a schematic diagram of the shell structure in this utility model.

[0030] Explanation of reference numerals in the attached figures

[0031] 1. Harmonic generator; 2. First filter; 3. First amplifier; 4. Second filter; 5. Second amplifier; 6. Third filter; 7. Detector; 8. Comparator; 9. Power supply module; 100. Housing; 200. PCB; 201. Pad clearance groove. Detailed Implementation

[0032] The specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of this utility model.

[0033] like Figure 1 As shown in the figure, this is a circuit block diagram of a frequency source provided by this utility model. The frequency source includes a harmonic generator 1, a first filter 2, a first amplifier 3, a second filter 4, a second amplifier 5, a third filter 6, a detector 7, a comparator 8, and a power supply module 9.

[0034] The input terminal of harmonic generator 1 is connected to the reference input signal. The output terminal of harmonic generator 1 passes through the first filter 2, the first amplifier 3, the second filter 4, the second amplifier 5 to the third filter 6 in sequence. The output terminal of the third filter 6 is divided into two paths. One path is output to the external load to form an output signal, and the other path is coupled by power and then passes through the detector 7 and the comparator 8 in sequence to output a high level.

[0035] The power supply module 9 is electrically connected to the harmonic generator 1, the first amplifier 3, the second amplifier 5, the detector 7, and the comparator 8, and is used to supply power to the harmonic generator 1, the first amplifier 3, the second amplifier 5, the detector 7, and the comparator 8.

[0036] Furthermore, in order to reduce the board area and optimize the spurious suppression index, the first filter 2, the second filter 4, and the third filter 6 are all surface acoustic wave filters with narrower bandwidth.

[0037] In some embodiments, the harmonic generator 1 is model FIN1002M5X, the first filter 2, the second filter 4 and the third filter 6 are model TA1491A, the first amplifier 3 and the second amplifier 5 are model MNA-5A+, the detector 7 is model ADL5501, the comparator 8 is model MAX9140, and the power module 9 is model MAX8510.

[0038] In summary, to clearly illustrate the specific design process and application effects, the main technical specifications of the frequency source in this utility model are described here. The frequency source has a reference input frequency of 120MHz, an input power of 0dBm to 4dBm, an RF output frequency of 1920MHz, an output power of 3dBm ± 2dB, and is required to have spurious suppression ≥70dBc within a 1GHz bandwidth, phase noise ≤-100dBc / Hz at 1kHz, and power consumption less than 0.55W at a +5V supply voltage.

[0039] To suppress spurious signals in the 1920MHz±120MHz range, surface acoustic wave filters are used before the first amplifier 3 and after the second amplifier 5 to enhance frequency selection filtering. The reference signal is multiplied, and its specific harmonic components are extracted and then amplified and filtered in multiple stages. This reduces the types of components, thereby reducing product power consumption and improving the utilization of PCB200 and installation space.

[0040] Furthermore, all filters and amplifiers in the link are of the same model, and harmonic generator 1 has strong driving characteristics, so no additional driving circuit and filtering circuit are required for the reference signal. Moreover, the implementation of all functions in the scheme is the inherent function of the hardware circuit, without the need for additional code control, and the circuit stability is high.

[0041] In this utility model, such as Figure 3 As shown, the frequency source also includes a housing 100 and a PCB 200. The PCB 200 is disposed on the inner bottom side of the housing 100. The harmonic generator 1, the first filter 2, the first amplifier 3, the second filter 4, the second amplifier 5, the third filter 6, the detector 7, the comparator 8, and the power supply module 9 are all disposed on the side of the PCB away from the inner bottom side of the housing 100.

[0042] In this utility model, "PCB" refers to the abbreviation of "Printed circuit board," which is the support for electronic components. "PCBA" is the abbreviation of "Printed Circuit Board Assembly," which refers to the process of assembling electronic components and chips onto a PCB200 through processes such as soldering, making it a circuit board assembly with specific functions.

[0043] The housing 100 in this invention is made of Kovar alloy and has external dimensions of 20mm × 20mm × 4.1mm. The PCB 200 has external dimensions of 18.1mm × 17.9mm × 0.9mm. Conventional designs require at least 40mm × 30mm × 8mm external dimensions. Even with a double-sided cavity using common screws, the PCB 200 requires at least four screws for fastening and at least seven main components. However, this invention uses a single-sided layout, saving space for screw mounting holes and reducing the number of main components to six. Furthermore, it does not involve software control. All circuit components are housed within the housing 100 cavity, ensuring electrical connection between the PCBA and the housing 100 and improving circuit reliability.

[0044] Specifically, such as Figure 2As shown, the main components of the frequency source in this utility model are arranged as follows: the harmonic generator 1 is located at the upper left corner of the PCB 200, the first filter 2 is located at the right side of the harmonic generator 1, the first amplifier 3 is located at the right side of the first filter 2, the second filter 4 is located below the first filter 2, the second amplifier 5 is located below the second filter 4, the third filter 6 is located at the lower right side of the second amplifier 5, the detector 7 is located below the third filter 6, the comparator 8 is located at the lower left side of the second amplifier 5, and the power supply module 9 is located at the lower left corner of the PCB 200.

[0045] In this invention, the PCB200 layout structure adopts a four-layer board structure. The use of a four-layer board for layout and routing ensures the integrity of the reference layer for communication signals, thereby guaranteeing signal stability.

[0046] In this utility model, due to the high component density on PCB200, in order to ensure that the solder between the housing 100 and PCB200 melts during soldering assembly, the components at the edge of PCB200 will not be displaced by the solder tension, the distance between the copper area of ​​PCB200 and the boundary of PCB200 is set to 0.15mm.

[0047] In this utility model, the distance between the lower boundary of the PCB200 and the inner wall of the housing 100 is 0.5mm, and the distance between the upper boundary, left boundary and right boundary of the PCB200 and the inner wall of the housing 100 is 0.2mm.

[0048] The defined boundary of PCB200 during processing is based on the inner boundary of housing 100, and reduced inward by 0.2mm. The distance between the lower boundary of PCB and the inner sidewall of housing 100 is 0.5mm. This is to avoid the insulator leads on housing 100 when PCB200 is installed inside housing 100. After PCB200 is placed inside housing 100, PCB200 is moved horizontally downward until the pads with electrical characteristics on PCB200 overlap with the insulator. The 0.5mm distance is to provide space for PCB200 to move horizontally downward.

[0049] Furthermore, in order to make the overall structure more compact and further reduce the product structure size, the edge of the PCB200 is provided with a pad clearance groove 201 that matches the shape of the insulator lead on the housing 100.

[0050] In this utility model, in order to enhance grounding continuity and ensure that the entire bottom surface of PCB200 is in full contact with the housing 100, the bottom surface of PCB200 is provided with a full-surface solder mask window.

[0051] In some embodiments, the exposed copper surface of the bottom window of the PCB200 is treated with an immersion gold process.

[0052] In the present utility model, as Figure 4 shown, in order to ensure the welding performance between the PCBA and the housing 100, the surface of the housing 100 is selected for gold plating treatment, and the thickness of the gold layer is greater than 1.5 μm. The bottom of the inner cavity of the housing 100 and the inner wall of the cover plate are flat, without special avoidance areas. The cover plate of the housing 100 and the housing 100 adopt a parallel sealing welding process, and the wall thickness of the side of the housing 100 is 0.75 mm.

[0053] The specific welding process flow between the PCBA and the housing 100 in the present utility model is as follows:

[0054] Step 1: Use high-temperature tape to paste the outer surface of the housing 100. The bonding should be flat, which can effectively prevent the pollution of the structure appearance by redundant substances and the scratching of the structure appearance caused by external forces during the welding process;

[0055] Step 2: Place the housing 100 with well-protected appearance on a heating table set at a temperature of 180 °C for preheating. Use an electric soldering iron to apply 183 °C solder wire to the bottom of the inner cavity. The amount of solder should cover the bottom area and have a slight surplus, and can form an inward concave triangle with the wall;

[0056] Step 3: Apply solder paste to the bottom surface of the inner cavity of the housing 100, apply solder paste to the solder pads on the surface of the PCB 200, and mount components. Use tweezers to pick up the PCB 200 with the solder paste applied on the front and place it into the housing 100 and move it downward until the insulator leads overlap with the solder pads. Clamp the entire structure with a fixture and place it flat on a heating table at a temperature of 250 °C. After the solder paste melts, the printed board and components are fixed by the surface tension of the solder.

[0057] After completing the above operations, it is necessary to check the welding effect. The specific inspection contents are as follows:

[0058] First, use a microscope to observe whether the PCB 200 exceeds the height of the internal insulator. If it is too high, rework and repair are required;

[0059] Second, use a microscope to observe whether the amount of solder in the welding area is full. For areas that do not meet the requirements, an electric soldering iron can be used to supplement the solder;

[0060] Third, use the short-circuit range of a multimeter to check whether the circuit near the welding area is short-circuited to the ground. If it is short-circuited, rework and repair are required.

[0061] When there are no above problems, it can be judged that the welding is qualified.

[0062] For products that need rework and repair, complete the repair according to the following steps:

[0063] Step 1: When PCB200 exceeds the height of the internal insulator, set the heating table temperature to 250℃; after the heating table temperature stabilizes, clamp the entire structure and place it flat on the heating table. Observe that after the solder melts, use two tweezers to repeatedly press the diagonal position of the PCBA to make the PCBA stick to the bottom of the structure. After the processing is completed, clamp the entire structure onto the high-temperature resistant cardboard to cool down and then re-inspect.

[0064] Step 2: When a short circuit occurs and rework is required, identify the location of the short circuit, use a rework station to process the short-circuited components, and then re-inspect them.

[0065] In summary, the frequency source provided by this utility model, through improvements in principle and specific design considerations for the PCB200 size, component layout, and internal cavity of the housing 100, enhances the reliability of circuit functionality, improves the utilization rate of the PCB200 and mounting space, and simultaneously improves the suppression of frequency source phase noise and spurious emissions while reducing product power consumption. Furthermore, by employing a mature small-scale gold-sealed structure process, and through the exploration and refinement of the process flow and specific parameters for soldering the PCBA into the internal cavity of the housing 100, and through application and verification on specific products, this technical solution has been proven to be effective and reliable.

[0066] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings; however, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, to avoid unnecessary repetition, the present invention will not describe various possible combinations separately. However, these combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A frequency source, characterized by, The application relates to a harmonic generator (1) for connecting a reference input signal, a first filter (2) connected to the output of the harmonic generator (1), a first amplifier (3) connected to the output of the first filter (2), a second filter (4) connected to the output of the first amplifier (3), a second amplifier (5) connected to the output of the second filter (4), a third filter (6) connected to the output of the second amplifier (5), the third filter (6) having a first output and a second output, the first output of the third filter (6) being connected to an external load, a detector (7) connected to the second output of the third filter (6), a comparator (8) connected to the output of the detector (7), and a power module (9) connected to the harmonic generator (1), the first amplifier (3), the second amplifier (5), the detector (7) and the comparator (8). The first filter (2), the second filter (4) and the third filter (6) are all surface acoustic wave filters. The application further relates to a housing (100) and a PCB (200), the PCB (200) being arranged on the inner bottom side of the housing (100), the harmonic generator (1), the first filter (2), the first amplifier (3), the second filter (4), the second amplifier (5), the third filter (6), the detector (7), the comparator (8) and the power module (9) being arranged on the PCB (200) away from the top side of the housing (100). The harmonic generator (1) is arranged at the upper left corner of the PCB (200), the first filter (2) is arranged at the right side of the harmonic generator (1), the first amplifier (3) is arranged at the right side of the first filter (2), the second filter (4) is arranged at the lower side of the first filter (2), the second amplifier (5) is arranged at the lower side of the second filter (4), the third filter (6) is arranged at the lower right side of the second amplifier (5), the detector (7) is arranged at the lower side of the third filter (6), the comparator (8) is arranged at the lower left side of the second amplifier (5), and the power module (9) is arranged at the lower left corner of the PCB. The PCB (200) adopts a four-layer board structure. The distance between the copper area of the PCB (200) and the boundary of the PCB (200) is 0.15 mm. The distance between the lower boundary of the PCB (200) and the inner side wall of the housing (100) is 0.5 mm, and the distances between the upper boundary, the left boundary and the right boundary of the PCB (200) and the inner side wall of the housing (100) are all 0.2 mm. The bottom surface of the PCB (200) is provided with a whole-area solder mask layer. ​ ​ 2. The frequency source of claim 1, wherein, ​ 3. The frequency source of claim 1, wherein, ​ 4. The frequency source of claim 3, wherein, ​ 5. The frequency source of claim 3, wherein, ​ 6. The frequency source of claim 5, wherein, ​ 7. The frequency source of claim 3, wherein, ​ 8. The frequency source of claim 3, wherein, ​ 9. The frequency source of claim 5, wherein, The edge of the PCB (200) is provided with a pad avoiding groove (201) matched with the shape of the insulating sub lead on the shell (100).

10. The frequency source of claim 3, wherein, The surface of the shell (100) is provided with a gold layer, the thickness of the gold layer is greater than 1.5 μm, and the side plate wall thickness of the shell (100) is 0.75 mm.

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