Repeatable swizzling patterns for capacitive and inductive noise cancellation

Abstract

Disclosed herein are swizzling techniques that may provide capacitive and inductive noise cancellation on a set of signal lines. Positive noise due to a capacitive coupling between attacker signal lines and near victim signal lines is, in part, cancelled by negative noise due to inductive coupling between the attacker signal lines and a far victim signal line. Repeatable swizzling patterns are set forth to transpose near victim signal lines and far victim signal lines in subsequent segments to facilitate the capacitive and inductive cancellation. The signal lines are optionally reordered by a final swizzling to restore the set's original ordering.

What is claimed is:  
     
         1 . An apparatus comprising: 
 a set of swizzle routes on N signal tracks suitable to being inserted into N concurrently active signal lines to reassign the order of a first plurality of the N concurrently active signal lines in a first portion of the N signal tracks to provide at least a first partial cancellation of capacitive and inductive noise for said first plurality of the N concurrently active signal lines, and    said set of swizzle routes on N signal tracks further suitable to being reinserted into the set of N concurrently active signal lines to reassign the order of a second plurality of the N concurrently active signal lines in a second portion of the N signal tracks to provide at least a second partial cancellation of capacitive and inductive noise for the second plurality of the N concurrently active signal lines.    
     
     
         2 . The apparatus of  claim 1  further comprising: 
 an initial portion of N concurrently active signal lines having an initial order in an initial portion of the N signal tracks;  
 a first portion of the N concurrently active signal lines having the first order in the first portion of the N signal tracks;  
 a first copy of the set of swizzle routes on the N signal tracks inserted into the N concurrently active signal lines between the initial portion and the first portion to reassign the order of the first plurality of the N concurrently active signal lines from the initial order to the first order;  
 an second portion of the N concurrently active signal lines having the second order in the second portion of the N signal tracks; and  
 a second copy of the set of swizzle routes on the N signal tracks inserted into the N concurrently active signal lines between the first portion and the second portion to reassign the order of the second plurality of the N concurrently active signal lines from the first order to the second order.  
 
     
     
         3 . The apparatus of  claim 2  wherein a first signal line of the N concurrently active signal lines is adjacent to an initial subset of signal lines in the initial portion of the N concurrently active signal lines, adjacent to a first subset of signal lines in the first portion of the N concurrently active signal lines, and adjacent to a second subset of signal lines in the second portion of the N concurrently active signal lines, the initial subset, the first subset and the second subset being disjoint.  
     
     
         4 . The apparatus of  claim 2  wherein the N concurrently active signal lines have a substantially common origin and a substantially common destination.  
     
     
         5 . The apparatus of  claim 2  comprising 
 a plurality of S copies of the set of swizzle routes on the N signal tracks to provide capacitive and inductive noise cancellation within the N concurrently active signal lines, S being computed for a particular value of N according to the equation, N 2 /2−(2S+3)N/2+S+1=0; and  
 an optional final copy of the set of swizzle routes on the N signal tracks to restore the initial order for the set of N concurrently active signal lines.  
 
     
     
         6 . The apparatus of  claim 5  wherein each of the N signal lines of the N concurrently active signal lines is placed adjacent to every other signal line of the N concurrently active signal lines in some portion of the N concurrently active signal lines.  
     
     
         7 . The apparatus of  claim 2  wherein the second portion of the N concurrently active signal lines has no signal line, of the N concurrently active signal lines, adjacent to one of the same signal lines that they are adjacent to in the first portion of the N concurrently active signal lines.  
     
     
         8 . The apparatus of  claim 7  wherein the second portion of the N concurrently active signal lines has no signal line, of the N concurrently active signal lines, adjacent to one of the same signal lines that they are adjacent to in the initial portion of the N concurrently active signal lines.  
     
     
         9 . A method comprising: 
 inserting a set of swizzle routes on N signal tracks suitable into N concurrently active signal lines to reassign the order of a first plurality of the N concurrently active signal lines in a first portion of the N signal tracks to provide at least a first partial cancellation of capacitive and inductive noise for said first plurality of the N concurrently active signal lines, wherein said set of swizzle routes on the N signal tracks is also suitable to being reinserted into the set of N concurrently active signal lines to reassign the order of a second plurality of the N concurrently active signal lines in a second portion of the N signal tracks to provide at least a second partial cancellation of capacitive and inductive noise for the second plurality of the N concurrently active signal lines.    
     
     
         10 . The method of  claim 9  further comprising: 
 reinserting the set of swizzle routes on the N signal tracks into the N concurrently active signal lines to reassign the order of a second plurality of the N concurrently active signal lines in a second portion of the N signal tracks to provide at least a second partial cancellation of capacitive and inductive noise for the second plurality of the N concurrently active signal lines.  
 
     
     
         11 . The method of  claim 2  further comprising: 
 inserting the set of swizzle routes on the N signal tracks into the N concurrently active signal lines S times to provide S stages of capacitive and inductive noise cancellation and optionally providing an additional stage to provide for restoring an initial order of the N concurrently active signal lines, wherein each of the N concurrently active signal lines is placed adjacent to every other signal line of the N concurrently active signal lines in some stage of the S stages, S being related to N according to the equation:  
   N   2 /2−(2 S+ 3) N/ 2+ S+ 1=0.