Abstract: Methods and apparatus for serial channel operation are disclosed. An N+1-level signaling scheme is used to transmit N staggered but overlapping NRZ sub-sequences concurrently on a serial channel. Each sequence has a bit rate R and an essential bandwidth of R Hz. The combined bit rate of the channel is N×R, but due to a lack of correlation between the sub-sequences, the essential bandwidth remains approximately R Hz. The signaling scheme also contains redundancy that allows some errors to be detected and/or corrected. Other embodiments are also described and claimed.

Abstract: A circuit board comprises a center segment distributing power and low-speed signaling, and outer segments for high-speed signaling. The segments use dielectric materials with different dielectric constants, with the outer segments supporting higher-speed signal transmission.

Abstract: A packet network device such as a network switch includes a number of functional cards or chassis modules at least some of which are connected to both an electrical backplane and a wireless backplane. The electrical backplane provides data plane signal paths and the wireless backplane provides control plane signal paths.

Abstract: Methods of designing a backplane, a backplane, and a packet switch using such a backplane are disclosed. The backplane comprises communication channels that connect each of a set of first card slots to each of a set of second card slots. Instead of forcing the backplane to route the communication channels to match a preset card configuration, the backplane communication channels are routed so as to reduce crosstalk and attenuation on at least the most difficult routing pairs. The cards perform logical translation of their backplane traffic to conform to the physical pin assignment for the particular card slot in which they are inserted. Other embodiments are also described and claimed.

Abstract: Circuit boards and methods for their manufacture are disclosed. The circuit boards carry high-speed signals using conductors formed to include lengthwise channels. The channels increase the surface area of the conductors, and therefore enhance the ability of the conductors to carry high-speed signals. In at least some embodiments, a discontinuity also exists between the dielectric constant within the channels and just outside the channels, which is believed to reduce signal loss into the dielectric material.

Abstract: Plated through holes pass through clearances in a ground plane of a circuit board. A conductive collar/spoke arrangement is constructed on the ground plane adjacent the clearance, to provide an inductive component to the coupling between a plated through hole and the ground plane. The inductive component impedes the transfer of high-frequency noise between the through hole and the ground plane. Other embodiments are also described and claimed.

Abstract: In one embodiment, a hybrid backplane coding scheme transmits data using lengthy sequences of scrambled data, separated by 8b/10b control character sequences that prepare the receiver for the next scrambled sequence and permit realignment if necessary. Advantageously, the sender of the scrambled data can be changed during the control character sequence. The hybrid backplane coding scheme can be designed such that the power spectral density of scrambled data and control character sequences are similar, which permits good performance with high-speed electrical differential receivers. Other embodiments are described and claimed.

Abstract: A circuit board comprises signaling through-holes that pass through a plurality of layers, including signal trace and digital ground plane layers, and power reference plane layers. Clearances are set to achieve a desired impedance characteristic for the through-holes. At a power reference plane layer, the clearance is defined around multiple neighboring through-holes.

Abstract: Circuit boards and methods for their manufacture are disclosed. The circuit boards carry high-speed signals using conductors formed to include lengthwise channels. The channels increase the surface area of the conductors, and therefore enhance the ability of the conductors to carry high-speed signals. In at least some embodiments, a discontinuity also exists between the dielectric constant within the channels and just outside the channels, which is believed to reduce signal loss into the dielectric material.

Abstract: A high-speed router backplane is disclosed. The router backplane uses differential signal pairs on multiple signal layers, each sandwiched between a pair of digital ground layers. Thru-holes are used to connect the differential signal pairs to external components. To reduce routing complexity, at least some of the differential signal pairs route through a via pair, somewhere along their path, to a different signal layer. At least some of the thru-holes and vias are drilled to reduce an electrically conductive stub length portion of the hole. The drilled portion of a hole includes a transition from a first profile to a second profile to reduce radio frequency reflections from the end of the drilled hole.

Abstract: A high-speed router backplane is disclosed. The router backplane uses differential signal pairs on multiple signal layers, each sandwiched between a pair of digital ground layers. To reduce routing complexity, at least some of the differential signal pairs route through a via pair, somewhere along their path, to a different signal layer. Specific via designs reduce differential signal distortion due to the via pair, allowing the backplane to operate reliably at differential signal rates in excess of 3 Gigabits per second. In particular, each via passes through nonfunctional conductive pads on selected digital ground plane layers, the pads separated from the remainder of its ground plane layer by a clearance, thereby modifying the impedance of the via and reducing reflections from the stubs created by the via.

Abstract: The disclosed board fabrication techniques and design features enable the construction of a reliable, high-layer-count, and economical backplane for routers and the like that require a large number of signaling paths across the backplane at speeds of 2.5 Gbps or greater, as well as distribution of significant amounts of power to router components. The disclosed techniques and features allow relatively thick (e.g., three- or four-ounce copper) power distribution planes to be combined with large numbers of high-speed signaling layers in a common backplane. Using traditional techniques, such a construction would not be possible because of the number of layers required and the thickness of the power distribution layers. The disclosed embodiments use novel layer arrangements, material selection, processing techniques, and panel features to produce the desired high-speed layers and low- noise high-power distribution layers in a single mechanically stable board.

Abstract: For electrical backplanes and the like, a power plane adaptation to improve the propagation of high-speed signals through clearances in an embedded power plane is disclosed. In exemplary embodiments, the power plane is segmented in a high-speed connector region, such that a portion of the metal layer that forms the power plane is retained in the high-speed connector region—but isolated from the power-delivery portion of the power plane. The isolated portion is connected to digital ground, and clearances are formed therein where high-speed signaling throughholes will pass through the region. In some embodiments, various attainable advantages include better manufacturability, better matching and control of high-speed signaling throughhole impedance, and improved noise isolation. Other embodiments are described and claimed.

Abstract: A high-speed router backplane is disclosed. The router backplane uses differential signal pairs on multiple signal layers, each sandwiched between a pair of digital ground layers. To reduce routing complexity, at least some of the differential signal pairs route through a via pair, somewhere along their path, to a different signal layer. Specific via designs reduce differential signal distortion due to the via pair, allowing the backplane to operate reliably at differential signal rates in excess of 3 Gigabits per second. In particular, each via passes through nonfunctional conductive pads on selected digital ground plane layers, the pads separated from the remainder of its ground plane layer by a clearance, thereby modifying the impedance of the via and reducing reflections from the stubs created by the via.

Abstract: For electrical backplanes and the like, a power plane adaptation to improve the propagation of high-speed signals through clearances in an embedded power plane is disclosed. In exemplary embodiments, the power plane is segmented in a high-speed connector region, such that a portion of the metal layer that forms the power plane is retained in the high-speed connector region—but isolated from the power-delivery portion of the power plane. The isolated portion is connected to digital ground, and clearances are formed therein where high-speed signaling throughholes will pass through the region. In some embodiments, various attainable advantages include better manufacturability, better matching and control of high-speed signaling throughhole impedance, and improved noise isolation. Other embodiments are described and claimed.

Abstract: The disclosed board fabrication techniques and design features enable the construction of a reliable, high-layer-count, and economical backplane for routers and the like that require a large number of signaling paths across the backplane at speeds of 2.5 Gbps or greater, as well as distribution of significant amounts of power to router components. The disclosed techniques and features allow relatively thick (e.g., three- or four-ounce copper) power distribution planes to be combined with large numbers of high-speed signaling layers in a common backplane. Using traditional techniques, such a construction would not be possible because of the number of layers required and the thickness of the power distribution layers. The disclosed embodiments use novel layer arrangements, material selection, processing techniques, and panel features to produce the desired high-speed layers and low-noise high-power distribution layers in a single mechanically stable board.

Abstract: A high-speed router backplane is disclosed. The disclosed construction and layout techniques enable the construction of a reliable, high-layer-count, and economical backplane for routers and the like that use signaling across the backplane at trace speeds of 2.5 Gbps or greater. Specific ranges of differential trace geometry characteristics, with significant single-ended coupling to adjacent ground planes, have been found to provide the parameters needed for such signaling. New trace routing and layering techniques also help in the realization of a backplane embodiment containing roughly 600 operable high-speed differential pairs, while also providing sufficient electromagnetic interference management to allow power distribution to occur within the same backplane.

Abstract: A high-speed, high-power modular router is disclosed. As opposed to conventional designs using optical backplane signaling and/or bus bars for power distribution, the disclosed embodiments combine high-power, low-noise power distribution with high-speed signal routing in a common backplane. Disclosed backplane features allow backplane signaling at 2.5 Gbps or greater on electrical differential pairs distributed on multiple high-speed signaling layers. Relatively thick power distribution layers are embedded within the backplane, shielded from the high-speed signaling layers by digital ground layers and other shielding features. A router using such a backplane provides a level of performance and economy that is believed to be unattainable by the prior art.

Abstract: The disclosed board fabrication techniques and design features enable the construction of a reliable, high-layer-count, and economical backplane for routers and the like that require a large number of signaling paths across the backplane at speeds of 2.5 Gbps or greater, as well as distribution of significant amounts of power to router components. The disclosed techniques and features allow relatively thick (e.g., three- or four-ounce copper) power distribution planes to be combined with large numbers of high-speed signaling layers in a common backplane. Using traditional techniques, such a construction would not be possible because of the number of layers required and the thickness of the power distribution layers. The disclosed embodiments use novel layer arrangements, material selection, processing techniques, and panel features to produce the desired high-speed layers and low-noise high-power distribution layers in a single mechanically stable board.

Abstract: A high-speed router backplane is disclosed. Because of the large number of high-speed conductive traces present in such a backplane, electromagnetic interference (EMI) can be a serious issue. And because such a router consumes significant amounts of power, some provision must exist (e.g., bus bars in the prior art) within the router for distributing power to the router components. In preferred embodiments, power distribution is accomplished using relatively thick (e.g., three- or four-ounce copper) power distribution planes within the same backplane used for high-speed signaling. To shield these planes from EMI, they are preferably placed near the center of the material stack, shielded from the signaling layers by adjacent digital ground planes. Also, where two power supply planes exist, the power supply planes are placed adjacent, further shielded by their respective power return planes.