CN111711468A

CN111711468A - FC-AE-1553 network system for data transmission by adopting coaxial cable

Info

Publication number: CN111711468A
Application number: CN202010541911.0A
Authority: CN
Inventors: 黄炳; 徐秀波; 赵志勇; 谢鹏; 冯昱程; 王超
Original assignee: Beijing Tasson Science and Technology Co Ltd
Current assignee: Beijing Tasson Science and Technology Co Ltd
Priority date: 2020-06-15
Filing date: 2020-06-15
Publication date: 2020-09-25
Anticipated expiration: 2040-06-15
Also published as: WO2021253800A1; CN111711468B

Abstract

The application discloses FC-AE-1553 network system for data transmission by adopting coaxial cable, which comprises: a switch and at least one network node, each of the network nodes connected to the switch by a pair of coaxial cables; the network node comprises a sending end and a receiving end, wherein the sending end and the receiving end of the network node respectively comprise a transformer and an SMA connector; at least two alternating current coupling capacitors are arranged between a primary coil and a secondary coil of the transformer, and two ends of each alternating current coupling capacitor are respectively connected with a digital ground and an SMA socket shell ground of the SMA connector; and the residual height of the welded pins of the SMA socket of the SMA connector is not higher than 1 mm.

Description

FC-AE-1553 network system for data transmission by adopting coaxial cable

Technical Field

The application relates to the technical field of communication networks, in particular to an FC-AE-1553 network system for data transmission by adopting a coaxial cable.

Background

The FC-AE (fibre Channel Avionics Environment) standard is a set of upper layer protocols (Up Level protocols) defined for Avionics system features. These upper layer protocols select a portion of the underlying applications of the FC base protocol suite, dedicated to several aspects of avionics commands, control, instrumentation, simulation, signal processing and sensors, video data distribution, and the like.

FC-AE-1553 is short for Fiber Channel environmental Upper Layer protocol MIL-STD-1553B (military standard 1553B for Upper Layer protocol in Fiber Channel Avionics), and is used for realizing mapping of a traditional MIL-STD-1553B Notice 2 bus protocol on an FC-4 Layer of a Fiber Channel so as to realize communication with certainty in a command/response mode in real-time aviation application.

The existing FC-AE-1553 network mostly adopts a transmission mode of optical fiber medium. The network of the optical fiber medium has the advantages of long transmission distance, light weight, excellent electromagnetic compatibility and the like. However, in some extreme environments, such as high temperature scenes with flame spraying, it is difficult for fiber optic cables to reliably operate for long periods of time. The scheme provides a method for transmitting FC-AE-1553 protocol by using coaxial cable. The problem that the optical fiber cable cannot tolerate a flame high-temperature scene can be solved.

The FC-AE-1553 uses coaxial transmission much like the MIL-STD-1553B bus uses shielded twisted pair transmission, which uses copper wire as the medium. However, the rate of MIL-STD-1553B is only 1Mbps, while the rate of FC-AE-1553 is as high as 1.0625 Gbps. To ensure that the transmission error rate of signals at such a high rate is less than the E-12 level, the coaxial FC-AE-1553 needs to be realized by a scheme different from the MIL-STD-1553.

Disclosure of Invention

Aiming at the problem that the FC-AE-1553 can not realize long-distance high-speed transmission by using a coaxial cable in the prior art, the application provides an FC-AE-1553 network system for carrying out data transmission by adopting the coaxial cable.

A first aspect of the embodiments of the present application provides an FC-AE-1553 network system that uses a coaxial cable for data transmission, including: a switch and at least one network node, each of the network nodes connected to the switch by a pair of coaxial cables; the network node comprises a sending end and a receiving end, wherein the sending end of the network node comprises a first transformer and a first SMA connector; the receiving end of the network node comprises a second transformer and a second SMA connector;

at least two alternating current coupling capacitors are arranged between a primary coil and a secondary coil of the first transformer, and two ends of each alternating current coupling capacitor are respectively connected with a digital ground and an SMA socket shell ground of the first SMA connector; at least two alternating current coupling capacitors are arranged between the primary coil and the secondary coil of the second transformer, and two ends of each alternating current coupling capacitor are respectively connected with a digital ground and an SMA socket shell ground of the second SMA connector;

and the residual height of the pins of the first SMA connector and the second SMA connector after the SMA sockets are welded is not higher than 1 mm.

In some embodiments, the switch comprises a sender and a receiver, wherein:

the receiving end of the switch communicates with the transmitting end of the network node through a first coaxial cable, and the transmitting end of the switch communicates with the receiving end of the network node through a second coaxial cable;

the transmitting end of the switch comprises a third SMA connector and a third transformer; the receiving end of the switch comprises a fourth SMA connector and a fourth transformer;

at least two alternating current coupling capacitors are arranged between the primary coil and the secondary coil of the third transformer, and two ends of each alternating current coupling capacitor are respectively connected with a digital ground and an SMA socket shell ground of the third SMA connector; at least two alternating current coupling capacitors are arranged between a primary coil and a secondary coil of the fourth transformer, and two ends of each alternating current coupling capacitor are respectively connected with a digital ground and an SMA socket shell ground of the fourth SMA connector;

and the residual heights of the pins of the third SMA connector and the fourth SMA connector after the SMA sockets are welded are not higher than 1 mm.

In some embodiments, the transmitting end and the receiving end of the network node further include a transmission line and a via hole, the transmission line is located on a printed board and is used for connecting components in the network node, and the differential impedance of the via hole on the printed board is 100 Ω ± 10%.

In some embodiments, the insertion loss of the printed board trace is not more than 0.024dB/inch at 1 GHz; the differential pair wires are equal in length, and the difference value is not more than 10 mil; the total length of FC high-speed differential routing on the network node is less than 10 inch; the differential wiring impedance is 100 omega +/-10%.

In some embodiments, the SMA socket axis signal references a complete SMA socket shell ground signal, the SMA socket shell ground signal is a complete continuous ground plane, and the SMA socket shell ground signal is a copper foil plane, the insertion loss of the SMA socket is not greater than 0.01dB at 1 GHz; not more than 0.02dB at 2 GHz.

In some embodiments, the SMA connector has a characteristic impedance of 50 Ω ± 10% and an insertion loss of no more than 0.01dB at 1 GHz; not more than 0.02dB at 2 GHz.

In some embodiments, the network node is a network controller and/or a network terminal.

In some embodiments, the via pairs of the printed board differential trace are not greater than 6 pairs, and the insertion loss of each via pair is not greater than 0.06dB at 1GHz and not greater than 0.1dB at 2 GHz.

According to the embodiment of the application, through the constraint design of wiring, layout and the transformer, the ideal transmission performance (transmission distance of 0-70 meters at 1.0625Gbps rate) can be achieved with extremely high reliability, and the special requirements of the specific field on system stability and transmission capacity are met.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings used in the description of the embodiments will be briefly introduced below. It is obvious that the drawings in the following description are only some embodiments of the application, and that it is also possible for a person skilled in the art to apply the application to other similar scenarios without inventive effort on the basis of these drawings. Unless otherwise apparent from the context of language or otherwise indicated, like reference numerals in the figures refer to like structures and operations.

FIG. 1 is a schematic diagram of a FC-AE-1553 network topology shown in accordance with some embodiments of the present application;

FIG. 2 is a link connection diagram of a FC-AE-1553 network system shown in accordance with some embodiments of the present application;

FIG. 3 is a schematic diagram of a network node transmit side architecture of a FC-AE-1553 network system according to some embodiments of the present application;

FIG. 4 is a schematic diagram of a network node receiving end structure of a FC-AE-1553 network system according to some embodiments of the present application;

FIG. 5 is a schematic diagram of a layout shown according to some embodiments of the present application;

fig. 6 is a graph illustrating a loss control curve for a coaxial cable according to some embodiments of the present application.

Detailed Description

In the following detailed description, numerous specific details of the present application are set forth by way of examples in order to provide a thorough understanding of the relevant disclosure. It will be apparent, however, to one skilled in the art that the present application may be practiced without these specific details. It should be understood that the use of the terms "system," "apparatus," "unit" and/or "module" herein is a method for distinguishing between different components, elements, portions or assemblies at different levels of sequential arrangement. However, these terms may be replaced by other expressions if they can achieve the same purpose.

It will be understood that when a device, unit or module is referred to as being "on" … … "," connected to "or" coupled to "another device, unit or module, it can be directly on, connected or coupled to or in communication with the other device, unit or module, or intervening devices, units or modules may be present, unless the context clearly dictates otherwise. For example, as used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

These and other features and characteristics of the present application, as well as the methods of operation and functions of the related elements of structure and the combination of parts and economies of manufacture, will be better understood upon consideration of the following description and the accompanying drawings, which form a part of this specification. It is to be expressly understood, however, that the drawings are for the purpose of illustration and description only and are not intended as a definition of the limits of the application. It will be understood that the figures are not drawn to scale.

Various block diagrams are used in this application to illustrate various variations of embodiments according to the application. It should be understood that the foregoing and following structures are not intended to limit the present application. The protection scope of this application is subject to the claims.

FIG. 1 is a schematic diagram of an FC-AE-1553 network topology shown in accordance with some embodiments of the present application. As shown in fig. 1, the coaxial FC-AE-1553 network adopts a star networking topology, that is, one FC switch is connected with a plurality of network nodes. A plurality of FC ports are provided on the FC switch, each port being connectable to a network node. The Network node may be a Network Controller (NC) or a Network Terminal (NT).

FIG. 2 is a link connection diagram of an FC-AE-1553 network system shown according to some embodiments of the present application. Each FC data transmission path contains a network node, a cable part, and a switch. The network node is connected to the switch by a pair of coaxial cables, divided into a transmit cable and a receive cable. As shown in fig. 2, the general structure of the network node includes a transmitting end and a receiving end, where the transmitting end of the network node includes: driver chip transmitters, transformers, sma (small a type) connectors (typically including a socket and a plug, preferably a socket on the device side and a plug in the cable); the receiving end of the network node comprises: drive chip receiver, transformer, SMA connector. Correspondingly, as shown in fig. 2, the switch includes a transmitting end and a receiving end, and the transmitting end of the switch includes: the system comprises an SMA connector, a transformer and a driving chip transmitter; the receiving end of the switch includes: SMA connector, transformer, drive chip receiver. The receiving end of the switch communicates with the transmitting end of the network node through a first coaxial cable (transmitting cable), and the transmitting end of the switch communicates with the receiving end of the network node through a second coaxial cable (receiving cable).

There are many factors that affect the signal transmission rate and transmission distance, and crosstalk between boards, line interference, and signal attenuation all have negative effects to different degrees. While inside the device, inter-board crosstalk is mainly generated by the wiring layout and device connections, the effect of which is greater when the communication rate is higher. In some embodiments, to satisfy the high rate transmission of coaxial cables, the network nodes need to be configured accordingly. At least two alternating current coupling capacitors are typically arranged between the primary coil and the secondary coil of the transformer, and two ends of each alternating current coupling capacitor are respectively connected with a digital ground and an SMA socket shell ground; and the residual height of the pins of the SMA connector after welding is not higher than 1 mm. Correspondingly, the exchanger needs to be configured in the same way, at least two alternating current coupling capacitors are arranged between the primary side and the secondary side of the transformer, and two ends of each alternating current coupling capacitor are respectively connected with a digital ground and an SMA socket shell ground; and the residual height of the pins of the SMA connector after welding is not higher than 1 mm. Through the mode of the embodiment, the technical scheme of the application optimizes the electrical performance in the transformer and the connector pin, can ensure that a communication device has good anti-interference performance and robustness in a high-speed transmission environment, and can stably transmit FC-AE-1553 network signals with 1.0625Gbps rate, so that the long-distance high-rate communication of the coaxial cable in the FC-AE-1553 network is realized.

Fig. 3 and 4 are schematic network node structures of FC-AE-1553 network systems according to some embodiments of the present application. As shown in the preferred embodiments of fig. 3 and 4, both the transmitting end and the receiving end of the network node include driving chips (transmitter and receiver), wires (transmission lines and vias), transformers, and SMA connectors.

In some embodiments of the present application, the FC-AE-1553 network system has certain restrictive requirements for wiring in order to achieve better inter-board electrical performance.

Preferably, the vias of the printed board differential traces between the driver chip receiver and the driver chip transmitter to the SMA socket correspond to no more than 6 pairs. The insertion loss of each pair of via holes is not more than 0.06dB at 1 GHz; not more than 0.1dB at 2 GHz.

Differential impedance control is also required to be performed on the via holes of the differential signal paths, and the differential impedance of the via holes is 100 omega +/-10%.

The insertion loss of the printed circuit board wiring is not more than 0.024dB/inch at 1 GHz; the differential pair wires are equal in length, and the difference value is not more than 10 mil; the total length of FC high-speed differential routing on the network node is less than 10 inch; the impedance of the differential routing is controlled to be 100 omega +/-10%.

In some embodiments, the FC-AE-1553 network system has certain restrictive requirements on the layout.

The layout is characterized in that:

(a) the routing of the primary (coil) of the transformer (U26) meets the condition of routing characteristic impedance (the characteristic impedance can be 50 ohm, 75 ohm, 120 ohm and the like according to the circuit requirement), and also meets the condition that the axis signal of the SMA socket needs to refer to a complete shell ground signal (GND _ EARTH) of the SMA socket. The SMA socket shell ground signal (GND _ EARTH) is a complete continuous ground plane, namely the SMA socket shell ground signal is designed to be a copper foil plane and cannot be connected in a wiring mode. As shown in the area of fig. 5A/B. GND _ EARTH is a complete continuous ground plane designed to stably transmit signals at 1.0625 Gbps.

(b) At least 2 AC coupling capacitors are placed between the primary and secondary windings of the transformer (U26). The capacitors are respectively connected with a digital Ground (GND) and an SMA socket shell ground signal (GND _ EARTH), as shown in the area C/D of FIG. 5. According to the capacitor layout position and the capacitor number designed by the embodiment of the application, the transmission quality of the error rate smaller than the E-12 order of magnitude can be obtained. Wherein, the number of the capacitors can be more than or equal to 2.

The requirements for the transformer are: the transformer can work at 1.0625Gbps speed and can be adapted to a 50 ohm coaxial cable. Such as using the PULSE TM 1062.

The requirements for SMA sockets are: the insertion loss of the SMA socket is not more than 0.01dB at 1 GHz; not more than 0.02dB at 2 GHz. As shown in fig. 5, the SMA sockets are part of the areas labeled J15 and J16.

Requirements for coaxial cables: the insertion loss of the cable part is not more than 15dB at 1 GHz; not more than 23dB at 2 GHz. The return loss of the coaxial cable is not more than-15 dB at 0-2 GHz. The insertion loss control of the coaxial cable should be better than the curve in fig. 6.

The coaxial cable comprises an inner core and a shielding layer, the inner core is connected with the positive end of the differential signal, the shielding layer is connected with the negative end of the differential signal, and the insertion loss of the coaxial cable is not more than 15dB at 1 GHz; not more than 23dB at 2GHz and not more than-15 dB at 0-2GHz return loss.

The characteristic impedance Z0 of the coaxial cable is 50 Ω ± 10%.

The attenuation characteristics of the cable can affect the distance over which the signal travels. The length of the transmission cable is 70 meters, and the loss of the cable is not more than 0.21dB/m at 1 GHz; not more than 0.32dB/m at 2 GHz; the length of the transmission cable is 50 meters, and the loss of the cable is not more than 0.3dB/m at 1 GHz; not more than 0.46dB/m at 2 GHz; the length of the transmission cable is 30 meters, and the loss of the cable is not more than 0.5dB/m at 1 GHz; not more than 0.77dB/m at 2 GHz.

The requirements for inter-coaxial crosstalk are: in the interval of 500MHz to 1GHz, the crosstalk attenuation quantity of the coaxial cable and other coaxial cables is not less than 40 dB.

The requirements for SMA connectors are: the characteristic impedance Z0 of the connector of the coaxial cable is 50 Ω ± 10%. The insertion loss of the SMA connector is not more than 0.01dB at 1 GHz; not more than 0.02dB at 2 GHz. And after the SMA socket of the SMA connector is electrically connected, redundant pins are cut off. The height of the connector pin residue is less than 1.0 mm. The residual height of the connector pin has obvious influence on the signal quality, and the signal reflection caused by the stub can be avoided by controlling the residual height, so that excellent signal quality is realized. And further, the bit error rate of the FC-AE-1553 protocol transmitted by the coaxial cable is lower than E-12 under the high-speed condition of 1.0625 Gbps.

Compared with the prior art, the application has the following beneficial effects:

compared with FC-AE-1553 optical fiber transmission, FC-AE-1553 coaxial transmission is more resistant to high temperature and can resist the high temperature of 125-250 ℃;

compared with MIL-STD-1553 shielded twisted pair transmission, the method provides a high-speed transmission scheme, and the transmission rate reaches 1.0625 Gbps;

and thirdly, the distance of 0-70 meters at the speed of 1.0625Gbps is transmitted by the constraint design of a driving chip (transmitter and receiver), wiring, layout, a transformer, an SMA connector and a cable.

It is to be understood that the above-described embodiments of the present application are merely illustrative of or illustrative of the principles of the present application and are not to be construed as limiting the present application. Therefore, any modification, equivalent replacement, improvement and the like made without departing from the spirit and scope of the present application shall be included in the protection scope of the present application. Further, it is intended that the appended claims cover all such changes and modifications that fall within the scope and range of equivalents of the appended claims, or the equivalents of such scope and range.

Claims

1. An FC-AE-1553 network system for data transmission using coaxial cable, the system comprising:

a switch and at least one network node, each of the network nodes connected to the switch by a pair of coaxial cables; the network node comprises a sending end and a receiving end, wherein the sending end of the network node comprises a first transformer and a first SMA connector; the receiving end of the network node comprises a second transformer and a second SMA connector;

2. The system of claim 1, wherein the switch comprises a sender and a receiver, wherein:

3. The system of claim 1, further comprising transmission lines and vias in the transmitter and receiver ends of the network node, the transmission lines being on a printed board for connecting components in the network node, wherein the differential impedance of the vias on the printed board is 100 Ω ± 10%.

4. The system of claim 3, wherein the insertion loss of the printed board trace is no greater than 0.024dB/inch at 1 GHz; the differential pair wires are equal in length, and the difference value is not more than 10 mil; the total length of FC high-speed differential routing on the network node is less than 10 inch; the differential wiring impedance is 100 omega +/-10%.

5. The system of claim 1, wherein the SMA socket axis signal references a complete SMA socket shell ground signal, the SMA socket shell ground signal is a complete continuous ground plane, and the SMA socket shell ground signal is a copper foil plane, the insertion loss of the SMA socket is not greater than 0.01dB at 1 GHz; not more than 0.02dB at 2 GHz.

6. The system of claim 1, wherein the SMA connector has a characteristic impedance of 50 Ω ± 10%, and an insertion loss of not more than 0.01dB at 1 GHz; not more than 0.02dB at 2 GHz.

7. The system according to claim 1, wherein the network node is a network controller and/or a network terminal.

8. The system of claim 3 or 4, wherein the pairs of vias of the printed board differential trace are no more than 6 pairs, and the insertion loss of each pair of vias is no more than 0.06dB at 1GHz and no more than 0.1dB at 2 GHz.