A printed circuit board containing a temperature compensated crystal oscillator and a miniaturized communication board card

Abstract

This invention discloses a printed circuit board (PCB) containing a temperature-compensated crystal oscillator (TCQO) and a miniaturized communication board. From the top to the bottom layer of the PCB, the boundary of the corresponding area where the TQO package is located is reserved with a gap greater than or equal to 2mm from the boundary of each layer. In all layers except the layer containing the TQO, the corresponding area where the TQO package is located is copper-clad. The grounding pin of the TQO is connected to the copper-clad area in the inner layer through a blind via. The power supply and output lines of the TQO adopt a serpentine design with a wire diameter no greater than 0.2mm and a wire length no less than 10mm. This invention, under the condition of using a 5032-packaged ordinary TQO in a BeiDou satellite receiver, solves the problem of low success rate in 1000-character long message communication on miniaturized, low-cost BeiDou boards through PCB structure design.

Description

Technical Field

[0001] This invention relates to a design scheme for a miniaturized communication board, and more particularly to a printed circuit board with a temperature-compensated crystal oscillator and a miniaturized communication board. Background Technology

[0002] The BeiDou Navigation Satellite System is a global satellite navigation system independently developed and constructed by my country. Its development can be divided into three stages: BeiDou-1, BeiDou-2, and BeiDou-3. All three stages require short message service, with BeiDou-3 requiring regional short message communication lengths of up to 1000 Chinese characters. For example... Figure 1 The diagram shows the device connection for short message communication functionality. Based on the design of the 30mm×40mm Beidou-2 board, a replacement design for the Beidou-3 board was carried out. It was found that the 5032-packaged ordinary temperature-compensated crystal oscillator used in the original Beidou-2 board had an extremely low success rate in testing the 1000-character long message communication function, making it difficult to meet the design requirement of greater than or equal to 95%.

[0003] The existing solution is to select high-performance crystal oscillators with higher temperature stability requirements, such as high-stability crystal oscillators and temperature-controlled crystal oscillators. However, these two types of crystal oscillators have the disadvantages of large size and high cost. In the design of miniaturized BeiDou satellite receiver boards, the layout of printed circuit boards (PCBs) is particularly tight. It is difficult to meet the miniaturized integrated design requirements by using large-sized crystal oscillators with high temperature stability, and the production cost of crystal oscillators using imported silicon-based materials is high. Summary of the Invention

[0004] Purpose of the invention: This invention proposes a printed circuit board with a temperature-compensated crystal oscillator and a miniaturized communication board. Under the condition that the Beidou satellite receiver uses a 5032 packaged ordinary temperature-compensated crystal oscillator, the invention solves the problem of low success rate of 1000-character long message communication of miniaturized and low-cost Beidou boards through PCB structure design.

[0005] Technical Solution: The technical solution adopted in this invention is a printed circuit board containing a temperature-compensated crystal oscillator (TCQSO), comprising: a top TOP layer to a bottom BOTTOM layer of the printed circuit board, wherein the boundary of the corresponding area of ​​the TQSO package location in each layer is reserved with a gap of not less than 2mm from the boundary of each layer; in the other layers except the layer where the TQSO is located, the corresponding areas of the TQSO package location in other layers are copper-plated, and the ground pin of the TQSO is connected to the copper-plated area in the inner layer through blind vias; the other inner layers except the TOP layer and BOTTOM layer where the TQSO is located are connected through buried vias, the buried vias are evenly distributed, and the ratio of the number of blind vias to the number of buried vias is 2:1; the power supply lines and output lines of the TQSO both adopt a serpentine line design.

[0006] The wire diameter of the power supply line and the output line of the temperature-compensated crystal oscillator shall not exceed 0.2mm, and the wire length shall not be less than 10mm.

[0007] In the bottom copper-clad area of ​​the printed circuit board, two blind vias are evenly placed near the inner layer buried via location for connection between the bottom copper-clad layer and the inner layer.

[0008] The circuitry connecting the bottom layer of the printed circuit board to the system ground is located on the periphery of the printed circuit board, using a serpentine line design with a line diameter of no more than 0.2mm and a line length of no less than 10mm.

[0009] The printed circuit board uses a gold finger interface.

[0010] The present invention also proposes a miniaturized communication board, including the above-mentioned printed circuit board with a temperature-compensated crystal oscillator.

[0011] The board and antenna are connected via a single internal power supply.

[0012] When the board transmits a message, the power amplifier is turned on for a set time period and then turned off. After the receipt is confirmed, the power amplifier is turned on again after a set time.

[0013] A specified time period is used for message confirmation during the power amplifier's startup process. If message transmission fails, the power amplifier will be turned off and will not be turned on again.

[0014] It adopts a dual-mode embedded board, which supports RNSS positioning and navigation, RDSS positioning, and short message communication functions.

[0015] Beneficial Effects: Compared with existing technologies, this invention has the following advantages: This invention changes the influence of PCB temperature on the temperature-compensated crystal oscillator by modifying the circuit structure design in the PCB, thereby improving the temperature stability coefficient of the temperature-compensated crystal oscillator and achieving the goal of increasing the communication success rate of transmitting 1000 Chinese characters. This method, without increasing additional hardware costs, ensures that the communication success rate of 1000-character long messages from BeiDou-3 meets the design requirements of the board's communication success rate, completing the localization and miniaturization design of the BeiDou-3 receiver. It also achieves cost reduction and efficiency improvement. According to actual test data, the success rate of 1000-character communication with the sky using a common 5032-packaged temperature-compensated crystal oscillator, with a frequency error ≤ ±2ppm and a temperature stability ≤ ±0.28ppm, has increased from no communication to 97.4% after modification. Attached Figure Description

[0016] Figure 1 This is a device connection diagram for short message communication functionality;

[0017] Figure 2 This is the PCB design layout diagram of the temperature-compensated crystal oscillator described in this invention;

[0018] Figure 3 This is a diagram showing the enabling function of the Beidou board to transmit 1000 Chinese characters in a telegram. Detailed Implementation

[0019] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0020] Example 1:

[0021] The printed circuit board containing a temperature-compensated crystal oscillator (TCQSO) according to this invention includes: a top layer (TOP) to a bottom layer (BOTTOM) of the printed circuit board, wherein the boundary of the corresponding area of ​​the TQSO package location in each layer is reserved with a gap of not less than 2mm from the boundary of each layer; in the layers other than the layer where the TQSO is located, the corresponding areas of the TQSO package location in other layers are copper-plated, and the ground pin of the TQSO is connected to the copper-plated area in the inner layer through blind vias; the inner layers other than the TOP and BOTTOM layers where the TQSO is located are connected through buried vias, the buried vias are evenly distributed, and the ratio of the number of blind vias to the number of buried vias is 2:1; the power supply lines and output lines of the TQSO both adopt a serpentine design. Figure 2 The diagram shows the PCB design structure of a temperature-compensated crystal oscillator. The structural features described above correspond to the following specific design considerations:

[0022] 1. A gap of at least 2mm should be reserved outside the temperature-compensated crystal oscillator package, and copper foil should not be laid on it. A pre-made gap area should be prepared.

[0023] 2. The gaps between the TOP and BOTTOM layers on the PCB board should be set according to the method in point one;

[0024] 3. In this example, the temperature-compensated crystal oscillator is placed on the TOP layer. The inner layers and BOTTOM layer below the crystal oscillator are all copper-clad. The size of the copper-clad area is the package size of the temperature-compensated crystal oscillator. The ground pin of the temperature-compensated crystal oscillator is connected to other layers using blind vias and buried vias.

[0025] IV. Layer 2 to Layer 9 are connected by buried holes to make the inner layers interconnected. The buried holes should be evenly distributed, and the ratio of blind buried holes to buried holes should be 2:1. The blind buried holes should be placed compactly.

[0026] 5. In the copper-clad area of ​​the BOTTOM layer, two blind vias are placed near the location of the buried vias in the inner layer to connect with the inner layer, so that the entire crystal oscillator ground layer is interconnected.

[0027] VI. The temperature-compensated crystal oscillator power supply adopts a serpentine wire design; the finer the wire diameter and the longer the wire length, the better. In this design, the wire length is not less than 10mm, and the wire diameter is not greater than 0.2mm. The output terminal of the temperature-compensated crystal oscillator is also designed according to the power supply wire design concept.

[0028] 7. When using the six-snake-line design method on the BOTTOM layer to connect the crystal oscillator's GND layer to the system GND layer, choose a location close to the outer edge of the PCB, following the... Figure 2 The grounding wire is set up using the design method.

[0029] Example 2:

[0030] Research revealed that the failure of the 1000-character short message communication on the third-generation board was due to the instantaneous large current generated during short message transmission, which significantly affected the stability of the temperature-compensated crystal oscillator (TCQO). This resulted in signal loss during signal reception, preventing normal short message service communication. The miniaturized communication board based on the TQO-integrated printed circuit board design described in Example 1 above overcomes this problem.

[0031] In this invention, the application scenario is a BeiDou-3 dual-mode embedded board, measuring 30mm × 40mm, with a gold finger interface. The board supports RNSS positioning and navigation, RDSS positioning, and short message communication. The board is connected to the antenna via a single-wire internal power supply.

[0032] When the Beidou board transmits 1000 Chinese characters, the power amplifier in the transmission channel needs to be turned on for 1 second, then turned off, and then turned on again after 2 seconds. This 250-millisecond activation period is used for message confirmation. If message transmission fails, the power amplifier activation sequence only includes the transmission time, not the message confirmation activation time. See the power amplifier activation diagram below. Figure 3 .

[0033] The PCB board designed according to the above-mentioned invention showed significant improvement in performance during actual testing. In a 1000-character short message communication test, 271 FKI statements were transmitted and 264 TCI statements were received, resulting in a communication success rate of 97.42%. FKI stands for transmit request and feedback status statements, and TCI stands for message communication information statements. This demonstrates the correctness of the design approach, the significant improvement effect, and the ability to greatly reduce product production costs and delivery cycles, fulfilling the requirements for domestic production and miniaturization, while also facilitating subsequent secondary integration design.

Claims

1. A printed circuit board containing a temperature-compensated crystal oscillator, characterized in that, include: From the top (TOP) layer to the bottom (BOTTOM) layer of the printed circuit board, a gap of no less than 2mm is reserved between the boundary of the corresponding area of ​​the temperature-compensated crystal oscillator (TCQSO) package location and the boundary of each layer. In the layers other than the layer where the TQSO is located, the corresponding areas of the TQSO package location are copper-clad, and the ground pin of the TQSO is connected to the copper-clad area in the inner layer through blind vias. The inner layers other than the TOP and BOTTOM layers where the TQSO is located are connected through buried vias, and the buried vias are evenly distributed. The ratio of the number of blind vias to the number of buried vias is 2:

1. The power supply lines and output lines of the TQSO adopt a serpentine design.

2. The printed circuit board with a temperature-compensated crystal oscillator according to claim 1, characterized in that: The wire diameter of the power supply line and the output line of the temperature-compensated crystal oscillator shall not exceed 0.2mm, and the wire length shall not be less than 10mm.

3. The printed circuit board with a temperature-compensated crystal oscillator according to claim 1, characterized in that: In the bottom copper-clad area of ​​the printed circuit board, two blind vias are evenly placed near the inner layer buried via location for connection between the bottom copper-clad layer and the inner layer.

4. The printed circuit board with a temperature-compensated crystal oscillator according to claim 1, characterized in that: The circuitry connecting the bottom layer of the printed circuit board to the system ground is located on the periphery of the printed circuit board, using a serpentine line design with a line diameter of no more than 0.2mm and a line length of no less than 10mm.

5. The printed circuit board with a temperature-compensated crystal oscillator according to claim 1, characterized in that: The printed circuit board uses a gold finger interface.

6. A miniaturized communication board, characterized in that: The printed circuit board containing a temperature-compensated crystal oscillator as described in any one of claims 1 to 5.

7. The miniaturized communication board according to claim 6, characterized in that: The board and antenna are connected via a single internal power supply.

8. The miniaturized communication board according to claim 6, characterized in that: When the board transmits a message, the power amplifier is turned on for a set time period and then turned off. After the receipt is confirmed, the power amplifier is turned on again after a set time.

9. The miniaturized communication board according to claim 8, characterized in that: A specified time period is used for message confirmation during the power amplifier's startup process. If message transmission fails, the power amplifier will be turned off and will not be turned on again.

10. The miniaturized communication board according to claim 6, characterized in that: It adopts a dual-mode embedded board, which supports RNSS positioning and navigation, RDSS positioning, and short message communication functions.

Images