摘要:
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.
摘要:
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.
摘要:
A serial channel switch circuit and modular packet switch using the serial channel switch circuits are disclosed. The serial channel switch circuit has a reconfigurable table for internal logical-to-physical channel switch translation. Depending on the slot in which a card containing such a serial channel switch circuit is inserted in the modular packet switch, its serial channel switch circuit may receive a different set of reconfigurable table values that are specific to that location. A global set of logical channel values can be applied to each card, which performs logical-to-physical channel mapping according to its location in the modular packet switch. Other embodiments are also described and claimed.
摘要:
A modular packet network device has a chassis in which multiple logic cards mate to the front side of an electrical signaling backplane. Logic power for the logic cards is supplied from a group of power converter cards that convert primary power to the logic voltages required by the logic cards. The power converter cards lie in a separate cooling path behind the backplane. Advantages achieved in at least some of the embodiments include removing primary power planes from the signaling backplane or portion of the backplane, providing redundant, upgradeable power modules whose individual failure does not cause logic card failure, and providing cool air to power converter circuits that would be subject to only heated air if located on the logic cards. Other embodiments are also described and claimed.
摘要:
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.
摘要:
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. Each power distribution plane can also include a conductive guard ring to shield that plane from EMI injected at the board edges. And where the backplane includes both high-speed and lower speed signaling traces, at least some lower speed signaling traces are placed on signaling layers, designated as low-speed, that are closest to the power distribution planes.
摘要:
A high-speed router backplane, and method for its fabrication, are disclosed. The backplane uses differential signaling trace pairs on multiple high-speed signaling layers, the high-speed signaling layers separated by ground planes. Plated signaling thru-holes connect the trace pairs to the board surface for connection to external components. The signaling thru-holes pass through clearances in each ground plane. At selected ground planes, a conductive pad is patterned within each high-speed signaling thru-hole clearance, the pad slightly larger than the thru-hole diameter. The pads affect the impedance characteristics of the thru-holes, thus providing a better impedance match to the differential trace pairs, reducing signal reflections, and improving the ability to signal across the backplane at high speeds.
摘要:
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.
摘要:
A modular packet network device has a chassis in which multiple logic cards mate to the front side of an electrical signaling backplane. Logic power for the logic cards is supplied from a group of power converter cards that convert primary power to the logic voltages required by the logic cards. The power converter cards lie in a separate cooling path behind the backplane. Advantages achieved in at least some of the embodiments include removing primary power planes from the signaling backplane or portion of the backplane, providing redundant, upgradeable power modules whose individual failure does not cause logic card failure, and providing cool air to power converter circuits that would be subject to only heated air if located on the logic cards. Other embodiments are also described and claimed.
摘要:
The characteristic impedance of a surface pad is manipulated by reticulating the pad and filling the spaces with a dielectric material, providing an inductive element in the coupling of the surface pad to an underlying ground pad of a ground plane, or a combination of these approaches. In appropriate embodiments, acceptable signal trace routing paths will exist in an embedded signal layer under the ground plane and crossing under the surface pad. Other embodiments are also described and claimed.