c( 1) c(0) c(1) Note z 1 represents a unit interval delay Figure 85 3 Transmit equalizer functional model

Transcription

1 Relace with the following: Tansmitted outut wavefom The 40GBASE-CR4 and 100GBASE-CR10 tansmit function includes ogammable equalization to comensate fo the fequency-deendent loss of the channel and facilitate data ecovey at the eceive. The functional model fo the tansmit equalize is the thee ta tansvesal filte shown in Figue Inut Outut z 1 c( 1 z 1 c(0 c(1 Note z 1 eesents a unit inteval delay Figue 85 3 Tansmit equalize functional model The state of the tansmit equalize and hence the tansmitted outut wavefom may be maniulated via the PD contol function defined in o via the management inteface. The tansmit function esonds to a set of commands issued by the link atne s eceive function and conveyed by a back-channel communications ath. This command set includes instuctions to a incement coefficient c(n, b decement coefficient c(n, c hold coefficient c(n at its cuent value, o d set the coefficients to a e-defined value (eset o initialize. In esonse, the tansmit function elays status infomation to the link atne s eceive function. The status messages indicate that a the equested udate to coefficient c(n has comleted (udated, b coefficient c(n is at its minimum value, c coefficient c(n is at its maimum value, o d coefficient c(k is eady fo the net udate equest (not_udated. The equiements fo the 40GBASE-CR4 and 100GBASE-CR10 tansmit equalize ae intended to be simila to the equiements fo 10GBASE-KR (efe to Howeve, the signal ath fom the tansmit function to TP2 intoduces fequency deendent loss and hase shift that distots the signal and makes it difficult to accuately chaacteize equalize efomance at TP2 using the methodology secified fo 10GBASE-KR. Instead the following ocess is defined fo the veification of tansmit equalize efomance at TP2. 1. The tansmitte unde test is eset e such that c( 1 and c(1 ae zeo and c(0 is its maimum value. Healey 7/15/2009 IEEE P802.3ba Task Foce 1

2 2. Catue at least one comlete cycle of the test atten PRBS9 (efe to at TP2 e Comute the linea fit to the catued wavefom e Define t to be the time whee the ising edge of the linea fit ulse,, fom ste 3 cosses 50% of its eak amlitude. 5. Samle the linea fit ulse,, at symbol-saced intevals elative to the time t 0 t 0.5 UI, inteolating as necessay to yield the samled ulse i. 6. Use i to comute the vecto of coefficients, w, of a N w -ta symbol-saced tansvesal filte that equalizes fo the tansfe function fom the tansmit function to TP2 e The aametes of the ulse fit and the equalizing filte ae given in Table The eak value of the linea fit ulse fom ste 3,, shall be geate than 240 mv. The RS value of the eo between the linea fit fom ste 3 and the measued wavefom, e, nomalized the eak value of the ulse,, must be no geate than Table 85-6 Nomalized tansmit ulse temlate Paamete Value, UI inea fit ulse length, N 7 inea fit ulse delay, D 1 Equalize length, N w 7 Equalize delay, D w 1 The eak value of linea fit ulse fom ste 3,, shall be geate than 240 mv. Fo each configuation of the tansmit equalize: 7. Configue the tansmitte unde test as equied by the test. 8. Catue at least one comlete cycle of the test atten PRBS9 (efe to at TP2 e Comute the linea fit to the catued wavefom e Define t to be the time whee the ising edge of the linea fit ulse,, fom ste 9 cosses 50% of its eak amlitude. 11. Samle the linea fit ulse,, at symbol-saced intevals elative to the time t 0 t 0.5 UI, inteolating as necessay to yield the samled ulse i. 12. Equalize the samled ulse i using the coefficient vecto, w, comuted in ste 6 e to yield the equalized ulse q i. The RS value of the eo between the linea fit fom ste 9 and the measued wavefom, e, nomalized the eak value of the ulse,, must be no geate than The nomalized amlitude of coefficient c( 1 is the value of q i at time t 0 (D w 1 UI. The nomalized amlitude of coefficient c(0 is the value of q i at time t 0 D w UI. The nomalized amlitude of coefficient c(1 is the value of q i at time t 0 (D w 1 UI. Healey 7/15/2009 IEEE P802.3ba Task Foce 2

3 Coefficient ste size The change in the nomalized amlitude of coefficient c(n coesonding to a equest to incement that coefficient shall be between and The change in the nomalized amlitude of coefficient c(n coesonding to a equest to decement that coefficient shall be between and The change in the nomalized amlitude of the coefficient is defined to be diffeence in the value measued to io to the assetion of the incement o decement equest (e.g. the coefficient udate equest fo all coefficients is hold and the value uon the assetion of a coefficient status eot of udated fo that coefficient Coefficient ange When sufficient incement o decement equests have been eceived fo a given coefficient, the coefficient will each a lowe o ue bound based on the coefficient ange o estictions laced on the minimum steady state diffeential outut voltage o the maimum eak-to-eak diffeential outut voltage. With c( 1 set to zeo and both c(0 and c(1 having eceived sufficient decement equests so that they ae at thei esective minimum values, the atio (c(0 c(1/(c(0 c(1 shall be geate then o equal to 4. With c(1 set to zeo and both c( 1 and c(0 having eceived sufficient decement equests so that they ae at thei esective minimum values, the atio (c(0 c( 1/(c(0 c( 1 shall be geate then o equal to Note that a coefficient may be set to zeo by fist asseting a coefficient eset equest and then maniulating the othe coefficients as equied by the test Wavefom acquisition The tansmitte unde test eetitively tansmits the secified test atten. The wavefom shall be catued with an effective samle ate that is times the signaling ate of the tansmitte unde test. The value of shall be an intege not less than 7. Aveaging multile wavefom catues is ecommended. The catued wavefom shall eesent an intege numbe of eetitions of the test atten totaling N bits. Hence the length of the catued wavefom should be N samles. The wavefom should be aligned such that the fist samles of wavefom coesond to the fist bit of the test atten, the second samles to the second bit, and so on inea fit to the wavefom measued at TP2 Given the catued wavefom k and coesonding aligned symbols (n deived fom the ocedue defined in , define the -by-n wavefom mati Y as shown in (85-1. Healey 7/15/2009 IEEE P802.3ba Task Foce 3

4 Y ( N 1 ( N 1 N 1 2 (85-1 Rotate the symbols vecto by the secified ulse delay D to yield. [ D 1 ( D 2 ( N (1 ( N D ] (85-2 ( Define the mati X to be an N-by-N mati deived fom as shown in (85-3. X (1 ( N (2 (2 (1 (3 ( N ( 1 N (1 (85-3 Define the mati X 1 to be the fist N ows of X concatenated with a ow vecto of 1 s of length N. The -by-(n 1 coefficient mati, P, coesonding to the linea fit is then defined by (85-4. P YX X (85-4 T T 1 1 ( X 1 1 In (85-4 the suescit T denotes the mati tansose oeato. E PX Y ( N 1 ( N 1 N 1 2 (85-5 The eo wavefom, k, is then ead column-wise fom the elements of E. Define P 1 to be a mati consisting of the fist N columns of the mati P as shown in (1 (2 P1 ( ( 1 ( 2 (2 ( ( N 1 1 ( ( N 1 2 ( N (85-6 The linea fit ulse esonse, (k, is then ead column-wise fom the elements of P Removal of the tansfe function between the tansmit function and TP2 Healey 7/15/2009 IEEE P802.3ba Task Foce 4

5 Rotate samled ulse esonse i by the secified equalize delay D w to yield as shown in (85-7. [ D 1 ( D 2 ( N (1 ( N D ] (85-7 i ( w i i i i w Define the mati P 2 to be an N -by-n mati deived fom as shown in (85-8. P 2 (1 ( N w (2 (2 (1 (3 ( N w ( 1 N w (1 (85-8 Define the mati P 3 to be the fist N w ows of P 2. Define a unit ulse column vecto of length N. The value of element (D 1 is 1 and all othe elements have a value of 0. The vecto of filte coefficients w that equalizes i is then defined by (85-9. T 1 w ( P P P ( T 3 Given the column vecto of equalize coefficients, w, the equalized ulse esonse q i is detemined by ( q i P 3 w (85-10 Healey 7/15/2009 IEEE P802.3ba Task Foce 5