The components of the six types of modules are PCB boards. The design structure and manufacturing process basically determine the performance indicators of the product. When domestic counterparts design their PCB boards, they often do not fully understand the failure mechanism, resulting in product performance indicators that are not high enough or cannot meet the requirements.
Implementation standards and definitions of important indicators
The six-type module implementation standard is EIA/TIA 568B.2-1, and the important parameters are insertion loss, return loss, near-end crosstalk, etc.
Insertion Loss: Due to the existence of the transmission channel impedance, it will increase the attenuation of the high-frequency components of the signal as the signal frequency increases. The attenuation is not only related to the frequency of the signal but also to the transmission distance. As the length increases, so does the signal attenuation. It is measured by the number of signal losses along the transmission channel per unit length, which represents the ratio of the signal strength of the source transmitter to the receiver signal strength.
Return Loss: Due to the change of impedance in the product, local oscillation will occur, resulting in signal reflection. A portion of the energy that is reflected by the transmitter will form noise, which will distort the signal and degrade transmission performance. For example, the full-duplex Gigabit network will mistake the reflected signal as the received signal, causing fluctuation of the useful signal and causing confusion. The less energy reflected, the better the impedance consistency of the line used by the channel, the more complete the transmission signal, and the less noise on the channel.
The calculation formula of return loss RL: return loss = transmitted signal ÷ reflected signal. In the design, ensuring the full line consistency of the impedance and cooperating with the six types of cables with 100-ohm impedance is the way to solve the failure of the return loss parameter. For example, the uneven distance between layers of the PCB circuit, the change of the copper conductor cross-section of the transmission line, the mismatch between the conductors in the module and the six types of cable conductors, etc., will cause the return loss parameters to change.
Near-End Crosstalk (NEXT): NEXT refers to the coupling of signals from one pair to the other in a pair of transmission lines, that is, when a signal is sent from one pair, it is received on another adjacent pair. signal of. This crosstalk signal is mainly due to capacitive or inductive coupling between adjacent pairs. How to reduce the signal coupled by capacitance or inductance, or to offset and weaken its interference signal by means of compensation, so that a standing wave cannot be generated, is the main method to solve the failure of this parameter.
Technology and Failure Mechanism
The content below is based on the trial production process of a Korean company’s super six-type module PCB board, serving as an important reference. During the module’s trial production stage, theoretical guidance and computer-aided design are utilized to quickly achieve desired outcomes. In China, the design of six types of module PCB boards is mainly guided by line diagonal compensation theory, with extensive trial production work leading to successful results. The following theories serve as valuable references.
1) Signal Leakage from Modules and Plugs
Signal interference can occur between signals on the link. To prevent this interference, conductors are twisted in balanced links for balanced transmission. Although this twisted structure can cause phase changes and signal attenuation, it helps achieve balanced transmission, known as Unshielded Structure (UTP). Each pair of the 4-pair balanced twisted pair has a different twist distance to achieve balance. Using modular connectors at the cable ends forms connections between connectors, creating a balanced structure in the interconnection area. Crosstalk occurs in the link, which is addressed through high-speed communication connector manufacturing technology to solve crosstalk issues. Contact loss may lead to attenuation and reflection loss, affecting high-speed signal transmission. Manufacturing connectors for high-speed communication aim to address such issues.
2) Explanation of Signal Leakage from Modules and Plugs
The connection line between modules and plugs consists of balanced connection terminals. Conductors in balanced lines may experience signal leakage and impedance losses, hindering communication. The solution to external leakage involves studying the E field and H field or employing reverse attenuation methods in high-speed communication connector manufacturing.
3) E Field and H Field
Electromagnetic field interference on balanced lines is described through E field and H field distributions. Key electronic communication line testing parameters consider relative measurements under swept frequency to transmit voice or data packets. Computer simulation technology helps analyze this aspect.
4) Solution to Signal Leakage
Addressing socket signal leakage involves collecting signals within the concentration area and returning them based on signal leakage simulation diagrams. Coupling capacitor design and compensation line parameters are vital, considering factors like line length, distance, width, and layout. Comprehensive computer simulations are necessary for designing compensation circuits in the face of signal transmission challenges in super six-type systems.
5) Overview of Domestic Six Types of Module Trial Production
Domestic counterparts generally design compensation circuits after determining the main circuit, conducting various scheme designs and sample productions. Once the compensation circuit and PCB layer structure are established, process improvement focuses on enhancing performance. Key areas for adjustment include interlayer gap parameters, copper foil thickness, main transmission line arrangement, and diagonal compensation methods for line pairs. Process parameter adjustments at PCB processing plants are also vital for successful module production.
Implementation standards and definitions of important indicators
The six-type module implementation standard is EIA/TIA 568B.2-1, and the important parameters are insertion loss, return loss, near-end crosstalk, etc.
Insertion Loss: Due to the existence of the transmission channel impedance, it will increase the attenuation of the high-frequency components of the signal as the signal frequency increases. The attenuation is not only related to the frequency of the signal but also to the transmission distance. As the length increases, so does the signal attenuation. It is measured by the number of signal losses along the transmission channel per unit length, which represents the ratio of the signal strength of the source transmitter to the receiver signal strength.
Return Loss: Due to the change of impedance in the product, local oscillation will occur, resulting in signal reflection. A portion of the energy that is reflected by the transmitter will form noise, which will distort the signal and degrade transmission performance. For example, the full-duplex Gigabit network will mistake the reflected signal as the received signal, causing fluctuation of the useful signal and causing confusion. The less energy reflected, the better the impedance consistency of the line used by the channel, the more complete the transmission signal, and the less noise on the channel.
The calculation formula of return loss RL: return loss = transmitted signal ÷ reflected signal. In the design, ensuring the full line consistency of the impedance and cooperating with the six types of cables with 100-ohm impedance is the way to solve the failure of the return loss parameter. For example, the uneven distance between layers of the PCB circuit, the change of the copper conductor cross-section of the transmission line, the mismatch between the conductors in the module and the six types of cable conductors, etc., will cause the return loss parameters to change.
Near-End Crosstalk (NEXT): NEXT refers to the coupling of signals from one pair to the other in a pair of transmission lines, that is, when a signal is sent from one pair, it is received on another adjacent pair. signal of. This crosstalk signal is mainly due to capacitive or inductive coupling between adjacent pairs. How to reduce the signal coupled by capacitance or inductance, or to offset and weaken its interference signal by means of compensation, so that a standing wave cannot be generated, is the main method to solve the failure of this parameter.
Technology and Failure Mechanism
The content below is based on the trial production process of a Korean company’s super six-type module PCB board, serving as an important reference. During the module’s trial production stage, theoretical guidance and computer-aided design are utilized to quickly achieve desired outcomes. In China, the design of six types of module PCB boards is mainly guided by line diagonal compensation theory, with extensive trial production work leading to successful results. The following theories serve as valuable references.
1) Signal Leakage from Modules and Plugs
Signal interference can occur between signals on the link. To prevent this interference, conductors are twisted in balanced links for balanced transmission. Although this twisted structure can cause phase changes and signal attenuation, it helps achieve balanced transmission, known as Unshielded Structure (UTP). Each pair of the 4-pair balanced twisted pair has a different twist distance to achieve balance. Using modular connectors at the cable ends forms connections between connectors, creating a balanced structure in the interconnection area. Crosstalk occurs in the link, which is addressed through high-speed communication connector manufacturing technology to solve crosstalk issues. Contact loss may lead to attenuation and reflection loss, affecting high-speed signal transmission. Manufacturing connectors for high-speed communication aim to address such issues.
2) Explanation of Signal Leakage from Modules and Plugs
The connection line between modules and plugs consists of balanced connection terminals. Conductors in balanced lines may experience signal leakage and impedance losses, hindering communication. The solution to external leakage involves studying the E field and H field or employing reverse attenuation methods in high-speed communication connector manufacturing.
3) E Field and H Field
Electromagnetic field interference on balanced lines is described through E field and H field distributions. Key electronic communication line testing parameters consider relative measurements under swept frequency to transmit voice or data packets. Computer simulation technology helps analyze this aspect.
4) Solution to Signal Leakage
Addressing socket signal leakage involves collecting signals within the concentration area and returning them based on signal leakage simulation diagrams. Coupling capacitor design and compensation line parameters are vital, considering factors like line length, distance, width, and layout. Comprehensive computer simulations are necessary for designing compensation circuits in the face of signal transmission challenges in super six-type systems.
5) Overview of Domestic Six Types of Module Trial Production
Domestic counterparts generally design compensation circuits after determining the main circuit, conducting various scheme designs and sample productions. Once the compensation circuit and PCB layer structure are established, process improvement focuses on enhancing performance. Key areas for adjustment include interlayer gap parameters, copper foil thickness, main transmission line arrangement, and diagonal compensation methods for line pairs. Process parameter adjustments at PCB processing plants are also vital for successful module production.
