# US 7,607,951 B2 · Differential pair inversion for reduction of crosstalk in a backplane system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,607,951 B2 - Document ID: US7607951B2 - Status: Granted - Kind: B2 - Application number: 12/015,369 - Filed: 2008-01-16 - Published: 2009-07-16 - Granted: 2009-10-27 - Earliest claimed: 2008-01-16 - Assignees: Amphenol Corporation - Inventors: Brian Peter Kirk - Web page: https://patentgrep.com/patent/US7607951B2 ## CPC - H05K 1/0245: {Lay-out of balanced signal pairs, e.g. differential lines or twisted lines} - H05K 1/0228: {Compensation of cross-talk by a mutually correlated lay-out of printed circuit traces, e.g. for compensation of cross-talk in mounted connectors (balanced signal pairs H05K1/0245)} - H05K 2201/044: Details of backplane or midplane for mounting orthogonal PCBs - H05K 2201/09236: Parallel layout - H05K 2201/09263: Meander - H05K 2201/10189: Non-printed connector - Y10S 439/941: Crosstalk suppression - Y10T 29/49124: On flat or curved insulated base, e.g., printed circuit, etc. - H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS - Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract A connection system has two connectors connected to each other by a plurality of differential signal pairs. The differential signal pairs alternate between a “straight connection” and a “reverse connection” between the connectors. The “straight connection” is formed by having a first signal trace connected from a positive launch in the first connector to a positive launch in the second connector, or P-P. And, the second signal trace has an N-N connection. The “reverse connection” has a first signal trace connected from a positive launch in the first connector to a negative launch in the second connector, or P-N. And, the second signal trace has a N-P connection. By inverting the pin connections of every other differential signal pair on the backplane, the forward crosstalk from the first connector is cancelled by the crosstalk generated by the second connector. ## Claims ### Claim 1 A connection system for connecting a first connector with a second connector on a circuit board, the system comprising: a first differential signal pair having a first signal line on the circuit board connected from a positive launch on the circuit board of the first connector to a positive launch on the circuit board of the second connector and a second signal line on the circuit board connected from a negative launch on the circuit board of the first connector to a negative launch on the circuit board of the second connector, and a second differential signal pair having a first signal line on the circuit board connected from another positive launch on the circuit board of the first connector to another negative launch on the circuit board of the second connector and a second signal line on the circuit board connected from another negative launch on the circuit board of the first connector to another positive launch on the circuit board of the second connector. ### Claim 2 (depends on 1) The connection system of claim 1, wherein said first differential signal pair is substantially the same length as said second differential signal pair. ### Claim 3 (depends on 1) The connection system of claim 1, wherein the positive and negative signal launches of the first differential signal pair at the first and second connectors is adjacent and imparts noise to the another positive and negative signal launches of the second differential signal pair at the first and second connectors. ### Claim 4 (depends on 1) The connection system of claim 1, wherein a first crosstalk is realized at the first connector and a second crosstalk is realized at the second connector, and the second crosstalk substantially cancels the first crosstalk. ### Claim 5 (depends on 1) The connection system of claim 1, wherein said first and second connectors are on a backplane. ### Claim 6 A connection system for a first connector having a negative signal launch and a positive signal launch and a second connector having a negative signal launch and a positive signal launch, the system comprising: a first differential signal pair having a first signal trace with a first end connected to the negative signal launch of the first connector and a second end connected to the negative signal launch of the second connector, and a second signal trace with a first end connected to the positive signal launch of the first connector and a second end connected to the positive signal launch of the second connector; and, a second differential signal pair having a first signal trace with a first end connected to the negative signal launch of the first connector and a second end connected to the positive signal launch of the second connector, and a second signal trace with a first end connected to the positive signal launch of the first connector and a second end connected to the negative signal launch of the second connector. ### Claim 7 (depends on 6) The connection system of claim 6, wherein said first differential signal pair is substantially the same length as said second differential signal pair. ### Claim 8 (depends on 6) The connection system of claim 6, wherein the positive and negative signal launches of the first differential signal pair at the first and second connectors is adjacent and imparts noise to the another positive and negative signal launches of the second differential signal pair at the first and second connectors. ### Claim 9 (depends on 6) The connection system of claim 6, wherein a first crosstalk is realized at the first connector and a second crosstalk is realized at the second connector, and the second crosstalk substantially cancels the first crosstalk. ### Claim 10 (depends on 6) The connection system of claim 6, wherein said first and second connectors are on a backplane. ### Claim 11 (depends on 6) The connection system of claim 6, further comprising: a third differential signal pair having a first signal trace with a first end connected to the negative signal launch of the first connector and a second end connected to the negative signal launch of the second connector, and a second signal trace with a first end connected to the positive signal launch of the first connector and a second end connected to the positive signal launch of the second connector; and, a fourth differential signal pair having a first signal trace with a first end connected to the negative signal launch of the first connector and a second end connected to the positive signal launch of the second connector, and a second signal trace with a first end connected to the positive signal launch of the first connector and a second end connected to the negative signal launch of the second connector. ### Claim 12 (depends on 11) The connection system of claim 11, wherein said first differential signal pair is adjacent the second differential signal pair, which is adjacent the third differential signal pair, which is adjacent the fourth differential signal pair. ### Claim 13 A connection system comprising: a first connector having a first negative signal launch, a second negative signal launch, a first positive signal launch and a second positive signal launch; a second connector having a first negative signal launch, a second negative signal launch, a first positive signal launch and a second positive signal launch; a first differential signal pair having a first signal trace with a first end connected to the first negative signal launch of the first connector and a second end connected to the first negative signal launch of the second connector, and a second signal trace with a first end connected to the first positive signal launch of the first connector and a second end connected to the first positive signal launch of the second connector; and, a second differential signal pair having a first signal trace with a first end connected to the second negative signal launch of the first connector and a second end connected to the second positive signal launch of the second connector, and a second signal trace with a first end connected to the second positive signal launch of the first connector and a second end connected to the second negative signal launch of the second connector. ### Claim 14 (depends on 13) The connection system of claim 13, wherein the first negative and positive signal launches of the first connector are adjacent to the second negative and positive signal launches of the first connector, and the first negative and positive signal launches of the first connector are adjacent to the second negative and positive signal launches of the second connector. ### Claim 15 (depends on 13) The connection system of claim 13, wherein said first differential signal pair is substantially the same length as said second differential signal pair. ### Claim 16 (depends on 13) The connection system of claim 13, wherein the first differential signal pair is adjacent the second differential signal pair and the second differential signal pair imparts noise to the first differential signal pair. ### Claim 17 (depends on 13) The connection system of claim 13, wherein a first crosstalk is realized at the first connector and a second crosstalk is realized at the second connector, and the second crosstalk substantially cancels the first crosstalk. ### Claim 18 (depends on 13) The connection system of claim 13, wherein said first and second connectors are on a backplane. ### Claim 19 A connection system for use with a first electronic element and a second electronic element, the system comprising a plurality of differential signal pairs, the differential signal pairs forming an alternating pattern of differential signal pairs having a straight connection between the first and second electronic elements and differential signal pairs having a reverse connection between the first and second electronic elements, wherein the straight connection is formed by having a first signal trace connected from a positive launch in the first electronic element to a positive launch in the second electronic element, and a second signal trace connected from a negative launch in the fist electronic element to a negative launch in the second electronic element, and the reverse connection is formed by a first signal trace connected from a positive launch in the first electronic element to a negative launch in the second electronic element and a second signal trace connected from a negative launch in the first electronic element to a positive launch in the second electronic element. ### Claim 20 A method for connecting a first connector with a second connector, the method comprising connecting a first signal line of a first differential signal pair from a positive launch of the first connector to a positive launch of the second connector; connecting a second signal line of the first differential signal pair from a negative launch of the first connector to a negative launch of the second connector, connecting a first signal line of a second differential signal pair from another positive launch of the first connector to another negative launch of the second connector, and connecting a second signal line of the second differential signal pair from another negative launch of the first connector to another positive launch of the second connector. ### Claim 21 (depends on 20) The method of claim 20, wherein said first differential signal pair is substantially the same length as said second differential signal pair. ### Claim 22 (depends on 20) The connection system of claim 20, wherein the positive and negative signal launches of the first differential signal pair at the first and second connectors is adjacent and imparts noise to the another positive and negative signal launches of the second differential signal pair at the first and second connectors. ### Claim 23 (depends on 20) The method of claim 20, wherein a first crosstalk is realized at the first connector and a second crosstalk is realized at the second connector, and the second crosstalk substantially cancels the first crosstalk. ### Claim 24 (depends on 20) The method of claim 20, wherein said first and second connectors are on a backplane.