Cable modem

Abstract

The utility model discloses a cable modem, including casing, circuit board, is equipped with main chip and upstream and downstream signal processing unit on the circuit board, and downstream signal processing unit is connected with modulation signal interface, still includes the fin, and the fin fixedly arranged on the circuit board, and the fin includes the contact piece, the connecting piece, the fin of integral structure, and the contact piece is contacted with main chip, and the connecting piece sets up in the contact piece four weeks to connect the fin, and the connecting piece is set up to the top of shell folding to the fin is set up to the outside folding of shell, and the circuit board on the outer periphery of main chip is equipped with a plurality of third vent, and the top of shell is equipped with first vent, and the bottom of shell is equipped with second vent. The utility model discloses the structure of fin has the special design to the space inside casing, has greater radiating area, and the circuit board below the fin is seted up third vent, and third vent and first, second vent cooperate and form the chimney effect, and it is favorable to better heat dissipation.

Description

Technical Field

[0001] This utility model relates to the field of communication equipment technology, and specifically to a cable modem. Background Technology

[0002] A cable modem is a device that provides high-speed internet access over a cable television network.

[0003] Cable modems are characterized by high main chip integration and significant heat generation. Current cable modem cooling systems typically only include ventilation holes on the casing, relying on natural air convection for heat dissipation, which is ineffective. Special attention must be paid to the operating environment during daily use; some operators even require prominent warnings such as "Do not stack with other devices" to be displayed on the casing, posing a safety risk.

[0004] Meanwhile, the transmission medium of cable modems is coaxial cable, and its signal frequency is between 5MHz and 1002MHz. Reliable shielding is required. Otherwise, it will not only introduce interference from external signals (such as the 700MHz and 850MHz frequency bands used by 4G and 5G in the communications field), leading to a decrease in the signal-to-noise ratio of the equipment and an increase in the bit error rate, but in severe cases, it will also affect the entire cable TV network. Summary of the Invention

[0005] The purpose of this invention is to provide a cable modem.

[0006] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0007] A cable modem includes a housing and a circuit board. The circuit board has a main chip, an uplink signal processing unit, and a downlink signal processing unit. The downlink signal processing unit is connected to a modulation signal interface. The modem also includes a heat sink, which is fixedly mounted on the circuit board. The heat sink includes an integrally structured contact piece, a connecting piece, and fins. The contact piece contacts the main chip, and the connecting piece is disposed around the contact piece to connect the fins.

[0008] The connecting piece is folded towards the top of the housing, and the fins are folded towards the outside of the housing;

[0009] The circuit board around the main chip is provided with several third ventilation holes, which are aligned with the fins.

[0010] The top of the housing is provided with a first ventilation hole, and the bottom of the housing is provided with a second ventilation hole.

[0011] As a further improvement of the present invention, the circuit board is also provided with a shielding cover, which includes a frame and a cover. The bottom of the frame is fixedly connected to the circuit board, and the cover is closed and disposed on the top of the frame to form an electromagnetic shielding space together with the frame and the circuit board.

[0012] The shielding cover is aligned with the uplink signal processing unit and the downlink signal processing unit, and the frame is provided with a partition to separate the uplink signal processing unit and the downlink signal processing unit.

[0013] As a further improvement of this utility model, the signal input pin of the modulation signal interface is connected to the circuit board using surface mount pins.

[0014] As a further improvement of this utility model, the circuit board is provided with a bare copper layer that matches the shape and size of the bottom edge of the frame, and the frame is soldered to the bare copper layer.

[0015] As a further improvement of the present invention, the modulation signal interface adopts an F-head structure, the modulation signal interface is connected to the frame by cross riveting, and the gap between the modulation signal interface and the frame is sealed by welding.

[0016] As a further improvement of this utility model, a temperature sensor for monitoring the temperature of the main chip is provided on the back of the circuit board.

[0017] As a further improvement of this utility model, foot pads are provided at the bottom corners of the shell.

[0018] As a further improvement of this utility model, a fourth ventilation hole is provided on the side of the housing.

[0019] As a further improvement of this utility model, the shell is made of thermoplastic material, the shield is made of metal material, and the cover of the shield does not contact the top inner surface of the shell.

[0020] Compared with the prior art, the technical advantages of this utility model are as follows:

[0021] The structure of the heat sink of this utility model adopts a special design for the internal space of the shell. The fins are folded around the main chip, which has a large heat dissipation area. A third ventilation hole is opened on the circuit board below the fins. The third ventilation hole, together with the first and second ventilation holes, forms a chimney effect, which is conducive to better heat dissipation.

[0022] By setting up a shielding cover to improve the shielding effect of the cable modem, external interference signals are prevented from entering the cable television network through the cable modem, which helps to improve network quality. The partition inside the frame separates the uplink and downlink signal processing units, which can prevent internal signals from interfering with each other. The frame and cover of the shielding cover are designed separately for easy maintenance.

[0023] The signal input pins of the modulation signal interface are connected to the circuit board using surface mount pins to reduce the impedance error of the signal traces. This avoids the series of problems caused by impedance mismatch, which can result in a section of the signal pin being left floating in conventional through-hole manufacturing processes. Attached Figure Description

[0024] Figure 1 This is an exploded structural diagram of the cable modem in a specific embodiment of this utility model;

[0025] Figure 2 This is a schematic diagram of the bottom of the shell in a specific embodiment of this utility model;

[0026] Figure 3 This is a schematic diagram of the structure on the back of the circuit board in a specific embodiment of this utility model;

[0027] Figure 4 This is a partially enlarged structural diagram of the shielding cover in a specific embodiment of this utility model;

[0028] Figure 5 This is a schematic diagram illustrating the principle of the chimney effect in a specific embodiment of this utility model. Detailed Implementation

[0029] The present invention will now be described in detail with reference to the specific embodiments shown in the accompanying drawings. However, these embodiments do not limit the present invention, and any structural, methodological, or functional modifications made by those skilled in the art based on these embodiments are included within the protection scope of the present invention.

[0030] Please see Figures 1 to 4 A cable modem includes a housing 1 and a circuit board 2. The circuit board 2 is provided with a main chip 3, an uplink signal processing unit 4, and a downlink signal processing unit 5. The downlink signal processing unit 5 is connected to a modulation signal interface 6 (for receiving modulation signals from a coaxial cable). The modem also includes a heat sink 7, which is fixedly disposed on the circuit board 2. The heat sink 7 includes an integrally structured contact piece 71, a connecting piece 72, and fins 73. The contact piece 71 contacts the main chip 3, and the connecting piece 72 is disposed around the contact piece 71 to connect the fins 73.

[0031] The connecting piece 72 is folded towards the top of the housing 1, and the fin 73 is folded towards the outside of the housing 1;

[0032] The circuit board 2 surrounding the main chip 3 is provided with a plurality of third ventilation holes 8, which are aligned with the fins 73.

[0033] The top of the housing 1 is provided with a first ventilation hole 9, and the bottom of the housing 1 is provided with a second ventilation hole 10.

[0034] Preferably, the heat sink 7 is made of aluminum, which reduces weight and lowers material and transportation costs compared to copper. Two diagonally spaced fixing holes are provided on the contact plate 71 of the heat sink 7, through which bolts connect the heat sink 7 and the circuit board 2. The bottom surface of the contact plate 71 contacts the top surface of the main chip 3.

[0035] Please see Figure 5 , Figure 5 This is a schematic diagram illustrating the chimney effect, with the arrows indicating the airflow direction. Several third ventilation holes 8 are located around the main chip 3 and below the heatsink 7 on the circuit board 2. When the main chip 3 and heatsink 7 are hot, the air above the circuit board 2 is heated, its density decreases, and it rises through the first ventilation hole 9 at the top of the housing 1. The temperature below the circuit board 2 is lower than above, and the cold air, due to its higher density, flows in through the second ventilation hole 10 at the bottom of the housing 1 and is blown onto the fins 73 through the third ventilation holes 8 on the circuit board 2, forming a circulation. The chimney effect facilitates better heat dissipation.

[0036] Furthermore, foot pads 11 are provided at the bottom corners of the housing 1. The foot pads 11 can raise the height of the bottom of the housing 1, so that there is a larger ventilation gap between the bottom of the housing 1 and the placement surface.

[0037] Furthermore, a fourth ventilation hole 12 is provided on the side of the housing 1. The fourth ventilation hole 12 is provided to optimize air convection inside and outside the housing 1.

[0038] Furthermore, a temperature sensor 13 for monitoring the temperature of the main chip 3 is provided on the back of the circuit board 2. The temperature sensor 13 is electrically connected to the main chip 3. When the temperature of the main chip 3 is detected to be higher than 90 degrees Celsius, the frequency of the main chip 3 is reduced to reduce the heat generation of the entire device.

[0039] As a further improvement of the present invention, the circuit board 2 is also provided with a shielding cover, which includes a frame 141 and a cover 142. The bottom of the frame 141 is fixedly connected to the circuit board 2, and the cover 142 is closed on the top of the frame 141 to form an electromagnetic shielding space together with the frame 141 and the circuit board 2.

[0040] The shielding cover is aligned with the uplink signal processing unit 4 and the downlink signal processing unit 5. The frame 141 is provided with a partition 143 to separate the uplink signal processing unit 4 and the downlink signal processing unit 5.

[0041] Furthermore, the circuit board 2 is provided with a bare copper layer (not shown) that matches the shape and size of the bottom edge of the frame 141, and the frame 141 is soldered to the bare copper layer.

[0042] Preferably, the circuit board 2 is also provided with pads for connecting the bottom of the frame 141. The bottom of the frame 141 is first soldered to the pads for positioning, and then the frame 141 is soldered to the bare copper layer for easier operation.

[0043] Soldering the frame 141 to the bare copper layer eliminates gaps at the connection between the frame 141 and the circuit board 2, helping the shielding cover to form a complete Faraday cage with better shielding effect. At the same time, after the frame 141 is connected to the bare copper layer, the shielding cover can also be used to dissipate heat from the circuit board 2.

[0044] Furthermore, the modulation signal interface 6 adopts an F-head structure, and the modulation signal interface 6 is connected to the frame 141 by a cross riveting 15. The mating gap between the modulation signal interface 6 and the frame 141 (the mating gap specifically refers to the annular gap between the outer surface of the modulation signal interface 6 and the mounting hole on the frame 141) is also sealed by welding.

[0045] To enhance the shielding effect and strengthen the connection between the modulation signal interface 6 and the shielding cover, the modulation signal interface 6 and the frame 141 of this invention are riveted using a cross riveting method with a thicker bevel, which is more robust than a single-line riveting. Furthermore, solder paste is introduced at the connection between the modulation signal interface 6 and the frame 141 to increase the conductivity of the modulation signal interface 6 and the shielding cover, thereby forming a complete Faraday cage inside the shielding cover and further enhancing the shielding performance.

[0046] Furthermore, the signal input pin of the modulation signal interface 6 is connected to the circuit board 2 via a surface mount pin 16.

[0047] The impedance of the modulation signal interface 6 of the coaxial cable and the cable modem is 75Ω. In order to reduce the error of the signal trace impedance, the signal input pin of the modulation signal interface 6 adopts the surface mount manufacturing process, which avoids the problem of a floating pin in the signal pin caused by the conventional plug-in process, which leads to a series of problems caused by impedance mismatch (such as signal reflection, attenuation, oscillation, crosstalk, interference with surrounding circuits or violation of electromagnetic compatibility standards).

[0048] Dangling pins manufactured using conventional plug-in processes can also create an antenna effect. Internally, this introduces interference signals from other external frequency bands (such as the 700MHz and 850MHz bands used in 4G and 5G communications) into the wired network environment. This can range from increasing signal noise, degrading the signal-to-noise ratio, and increasing the bit error rate in the interfering frequency band of the cable modem, to severely interfering with related frequency bands throughout the network, rendering those bands unusable. Externally, it radiates strong uplink signals, interfering with surrounding circuits and violating electromagnetic compatibility standards.

[0049] The present invention uses a surface mount pin 16 to avoid the above problems and has better impedance matching and shielding effect.

[0050] Furthermore, the housing 1 is made of thermoplastic material, and the shielding cover is made of metal material. The cover 142 of the shielding cover does not contact the inner top surface of the housing 1. To prevent damage to the housing 1 during heat dissipation, a gap is left between the shielding cover and the housing 1 to avoid contact.

[0051] Compared with the prior art, the technical advantages of this utility model are as follows:

[0052] The structure of the heat sink 7 of this utility model adopts a special design for the internal space of the housing 1. The fins 73 are folded around the main chip 3, which has a large heat dissipation area. A third ventilation hole 8 is opened on the circuit board 2 below the fins 73. The third ventilation hole 8, together with the first and second ventilation holes, forms a chimney effect, which is conducive to better heat dissipation.

[0053] By setting up a shielding cover, the shielding effect of the cable modem is improved, ensuring that external interference signals will not enter the cable television network through the cable modem, which helps to improve network quality; the partition 143 inside the frame 141 separates the uplink and downlink signal processing units, which can avoid mutual interference between internal signals; the frame 141 and cover 142 of the shielding cover adopt a split design, which facilitates maintenance.

[0054] The signal input pin of the modulation signal interface 6 is connected to the circuit board 2 via a surface mount pin 16 to reduce the error of the signal trace impedance and avoid a series of problems caused by impedance mismatch, which would result in a section of the signal pin being left floating in the conventional through-hole process.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it; although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the various embodiments of this utility model.

Claims

1. A cable modem, comprising a housing and a circuit board, wherein the circuit board is provided with a main chip, an uplink signal processing unit, and a downlink signal processing unit, the downlink signal processing unit being connected to a modulation signal interface, characterized in that, It also includes a heat sink, which is fixedly mounted on the circuit board. The heat sink includes an integrally structured contact piece, connecting piece, and fins. The contact piece contacts the main chip, and the connecting piece is disposed around the contact piece to connect the fins. The connecting piece is folded towards the top of the housing, and the fins are folded towards the outside of the housing; The circuit board around the main chip is provided with several third ventilation holes, which are aligned with the fins. The top of the housing is provided with a first ventilation hole, and the bottom of the housing is provided with a second ventilation hole.

2. A cable modem according to claim 1, characterized in that, The circuit board is also provided with a shielding cover, which includes a frame and a cover. The bottom of the frame is fixedly connected to the circuit board, and the cover is disposed on the top of the frame to form an electromagnetic shielding space together with the frame and the circuit board. The shielding cover is aligned with the uplink signal processing unit and the downlink signal processing unit, and the frame is provided with a partition to separate the uplink signal processing unit and the downlink signal processing unit.

3. A cable modem according to claim 1, characterized in that, The signal input pins of the modulation signal interface are connected to the circuit board via surface mount pins.

4. A cable modem according to claim 2, characterized in that, The circuit board has a bare copper layer that matches the shape and size of the bottom edge of the frame, and the frame is soldered to the bare copper layer.

5. A cable modem according to claim 2, characterized in that, The modulation signal interface adopts an F-type connector structure and is connected to the frame by cross riveting. The gap between the modulation signal interface and the frame is also sealed by welding.

6. A cable modem according to claim 1, characterized in that, The back of the circuit board is equipped with a temperature sensor for monitoring the temperature of the main chip.

7. A cable modem according to claim 1, characterized in that, Foot pads are provided at the bottom corners of the shell.

8. A cable modem according to claim 1, characterized in that, The side of the housing is provided with a fourth ventilation hole.

9. A cable modem according to claim 2, characterized in that, The housing is made of thermoplastic material, and the shield is made of metal material. The cover of the shield does not contact the top inner surface of the housing.

Images