Effect of a Frequency Perturbation in a Chain of Syntonized Transparent Clocks

Transcription

1 Effect of a Fequency Petubaton n a Chan of Syntonzed anspaent Clocs Geoffey M. Gane SAMSUNG Electoncs (Consultant) EEE 80. AVB G gmgane@comcast.net :

2 Outlne ntoducton ansfe functon fo a chan of syntonzed Cs Stablty analyss fo vaaton of fequency offset as a functon of numbe of hops Unflteed phase eo accumulaton ove multple hops Wande toleance equements Flteed phase accumulaton at endpont Splt path syntonzaton scenao Conclusons Refeences SAMSUNG Electoncs EEE 80. AVB Mach 007

3 ntoducton - Recent dscussons on the 588 (see [] and []) and 80. eflectos and n AVB mng calls and geneal AVB calls have ased concens that a chan of syntonzed clocs may exhbt excessve tte amplfcaton and accumulaton due to gan peang t s stated n [] that the tte accumulaton may be excessve when the peod of the petubaton s of the ode of twce the fequency measuement nteval t s well-nown that lage tte and wande accumulaton n a chan of PLLs may occu due to excessve gan peang Ealy analyss done n [3] analytcally usng chan of nd ode PLLs wth 40 db/decade oll-off Model eflected PDH egeneatos commonly used n telecommuncatons netwos at the tme (98) Late analyses done fo SDH/SONE and ON (see [4] fo detals of the ON analyses) hese models wee smla to those n [3]; man dffeence was the use of PLL models wth 0 db/decade oll-off All the analyses showed that f gan peang does not exceed 0. db the espectve tte equements ae met fo chans of 50 egeneatos (assumng egeneatos also meet espectve tte tansfe and geneaton equements) 50 egeneatos s a common Hypothetcal Refeence Model (see Appendx of [4] fo ON) SAMSUNG Electoncs EEE 80. AVB Mach 007 3

4 ntoducton - As a esult of these and smla analyses the gan peang of egeneatos and clocs n telecommuncatons netwos s lmted to 0. db he above analyses ae fo nd ode PLLs whch have nheent gan peang Howeve the syntonzaton pocess fo a tanspaent cloc (C) s not a nd ode PLL Pevously thee has not been a caeful evaluaton of the tansfe functon to detemne f gan peang s pesent Snce the C output s a syntonzed fequency the mmedate tansfe functon of nteest s the elaton between nput and output fequency offsets Howeve effect on phase accumulaton at a collocated odnay cloc (OC) s also of nteest n the pesent contbuton we evaluate the tansfe functon fo a C that syntonzes and evaluate accumulaton of Fequency offset Phase eo We also dscuss wande toleance and show ntal esults fo flteed phase eo at an endpont Fnally we nvestgate phase eo accumulaton usng the altenatve splt path syntonzaton descbed n [8] SAMSUNG Electoncs EEE 80. AVB Mach 007 4

5 ansfe Functon fo a C - Node Numbeng conventons (ntal node s GM followed by Cs) Snusodal petubaton appled to C GM C C C 3 C N Node numbeng used hee Node numbeng used n [6] Node 0 Node Node Node 3 Node N Node Node Node 3 Node 4 Node N n the followng notaton and analyss we use the node numbeng conventon above (the node numbeng of [6] s shown fo use when compang esults hee wth those of [6]) Each C pefoms a fequency update evey M th synch nteval (on ecept of Sync and Follow_Up fo that nteval) and that fequency update s done befoe the measuement of esdence tme Assume pefect maste (.e. gandmaste) Neglect phase measuement ganulaty SAMSUNG Electoncs EEE 80. AVB Mach 007 5

6 ansfe Functon fo a C - Notaton ndex of Sync message sent fo whch a fequency update s pefomed (f a fequency update s pefomed evey M Synch messages then ths s actually the M th Sync message). he fst Sync message s labeled 0. ndex of node numbe. he maste cloc at the begnnng of the chan s labeled 0; the Cs ae labeled... N. actual fequency offset of C elatve to the maste cloc dung the fequency update nteval between the th and () st Sync messages μ measued fequency offset of C elatve to the maste cloc when the th Sync and Follow_Up messages ave. Note that f the measuement pocess wee pefect then the measued value would be equal to the actual fequency offset dung the pevous fequency update nteval.e. μ. Howeve n geneal the measuement pocess s mpefect and ths s not tue. measued esdence tme of Sync message at C. Note that ths wll dffe fom deal esdence tme elatve to the maste cloc due to the fequency offset of C. deal esdence tme elatve to the pefect maste. fequency update nteval elatve to the pefect maste. m coected maste tme at C when th Sync message s eceved (.e. coected fo the esdence tmes of Cs... -). Note that m 0 s the tme the th Sync message s actually sent elatve to the maste cloc. SAMSUNG Electoncs EEE 80. AVB Mach 007 6

7 ansfe Functon fo a C - 3 Coected maste tme at node s gven by m m 0 Resdence tme at C s elated to fequency offset by ) ( hen m m 0 he measued fequency offset at C s equal to the ato of the elapsed local tme dung a fequency update nteval to the elapsed coected maste tme dung the same nteval mnus hs may be wtten as (see next slde) SAMSUNG Electoncs EEE 80. AVB Mach 007 7

8 SAMSUNG Electoncs EEE 80. AVB Mach ansfe Functon fo a C - 4 ( ) ( ) ( ) ( ) ( ) 0 0 ) ( ) ( m m μ

9 SAMSUNG Electoncs EEE 80. AVB Mach ansfe Functon fo a C - 5 Fequency s adusted by educng the cuent fequency by an amount equal to the measued fequency offset of the C elatve to ts maste he new fequency offset s elated to the old by nsetng the pevous equaton fo nto the above poduces μ μ ( ) ( ) ( ) ( ) ( ) ( ) ( ) ) ( ) ( ) ( O O O

10 ansfe Functon fo a C - 6 he esult to fst ode n the fequency offsets s ( ) May obtan a ecusve fom by ewtng the above fo ndex - and subtactng; the bounday condton fo s obtaned by substtutng n the above. he esult s ( ) > he above s a patal dffeence equaton wth a bounday condton SAMSUNG Electoncs EEE 80. AVB Mach 007 0

11 Stablty Analyss - Assume the maste s pefect and mpose a snusodal fequency petubaton at C ( ) 0 0 Ae ω A ampltude of the fequency offset petubaton (n convenent unts e.g. ppm ns/s dmensonless etc.) ω fequency of petubaton n ad/s - (note that wll not be used as an ndex hee) he bounday condton (equaton above that elates the fequency offsets at Cs and ) becomes A e ω ( e ω ) SAMSUNG Electoncs EEE 80. AVB Mach 007

12 Stablty Analyss - o obtan the complex fequency esponse to a snusodal petubaton fo the fequency offset at C fst tae the z-tansfom of the patal dffeence equaton and then set z e ω N H ( e ( z) N ( z) z ) ω ω e Whee N (z) z-tansfom of H(e ω ) snusodal tansfe functon Fequency esponse at C obtaned by multplyng the fequency esponse at C by the snusodal tansfe functon ased to the - powe SAMSUNG Electoncs EEE 80. AVB Mach 007

13 SAMSUNG Electoncs EEE 80. AVB Mach Stablty Analyss - 3 he ampltude of the fequency esponse s gven by (see the accompanyng contbuton fo ntemedate steps) Maxmum value of the above expesson occus fo ω π Petubaton fequency s the Nyqust ate.e. one-half the fequency update ate Petubaton peod s twce the fequency update peod ) ( e e e A ω ω ω [ ] ( ) cos ) cos ( ) ( e N ω ω ω ) ( - max e N ω

14 Stablty Analyss - 4 Magntude of wost-case fequency offset accumulaton depends on how long the fequency update nteval s compaed to the esdence tme.e. / and on the numbe of hops Fo example fo / 0.00 the wost-case fequency offset ampltude afte 00 hops s N ( e ω ) max 8 ( 0.00)[.00] n AVB netwos t s planned to hold Sync untl Follow_Up aves n wost case esdence tme could be equal to the synch nteval A value consdeed fo the fequency update nteval s 0 synch ntevals hen could have n wost case / 0. Fo a 7-hop netwo the wost case fequency offset accumulaton s N ( e ω ) max 5 ( 0.)[.] SAMSUNG Electoncs EEE 80. AVB Mach 007 4

15 Stablty Analyss - 5 Fo 0 hops N ( e ω ) max 8 ( 0.)[.] Fo hops N ( e ω ) max 9 ( 0.)[.].03 Fequency offset does not accumulate to the magntude of the petubaton untl the th hop May be ased why the fequency offset downsteam of the petubaton s not at least as lage as the petubaton tself C s stll syntonzng to the maste Fequency at an ntemedate C only affects the esdence tme and only to the extent that successve esdence tmes (.e. at successve fequency update tmes) ae dffeent SAMSUNG Electoncs EEE 80. AVB Mach 007 5

16 Stablty Analyss - 6 Fequency offset accumulaton facto Fequency offset accumulaton facto N N N / 0. / 0.0 / 0.00 C numbe Fgue. Facto by whch fequency offset ampltude due to appled snusodal petubaton accumulates as a functon of C numbe fo seveal atos /. SAMSUNG Electoncs EEE 80. AVB Mach 007 6

17 Stablty Analyss - 7 Fequency esponse at successve Cs fo / 0.00(obtaned usng Mathcad) b sub sub / sub N n C numbe Petubaton appled at C N n N n N n3 N n4 N n5 N n omega n SAMSUNG Electoncs EEE 80. AVB Mach 007 7

18 Stablty Analyss - 8 Fequency esponse at successve Cs fo / 0.0(obtaned usng Mathcad) b sub 3 sub / sub N n C numbe Petubaton appled at C N n N n N n3 N n4 K` // / c `_ czy Z`_/Z /Z_ cc`c N n5 N n omega n SAMSUNG Electoncs EEE 80. AVB Mach 007 8

19 Stablty Analyss - 9 Fequency esponse at successve Cs fo / 0.(obtaned usng Mathcad) 0.9 b sub 5 sub / sub 0. N n C numbe Petubaton appled at C N n N n N n3 N n4 N n5 N n6 N n7 N n8 N n omega n SAMSUNG Electoncs EEE 80. AVB Mach 007 9

20 Unflteed Phase Eo Accumulaton - Refeence [6] cted a geneal fom fo phase eo accumulaton G n G a 0 Specfc values of G 0 and a obtaned n [6] wee dffeent fo those obtaned n above fo accumulaton of fequency offset n ths secton ths dscepancy s futhe nvestgated and esolved Use above esults fo fequency offset accumulaton to compute total phase eo accumulaton unde the assumpton that an OC s collocated wth each C nteested n component of phase eo accumulaton due to snusodal petubaton appled at C he phase eo at a C s the dffeence between the tmestamp of a Sync message when t aves at a C and the tmestamp of the Sync message when t left the maste coected fo Popagaton tmes on upsteam lns Resdence tmes at upsteam Cs f esdence and popagaton tme measuements wee pefect we would coect fo these eos exactly and could educe phase eo accumulaton to nea zeo SAMSUNG Electoncs EEE 80. AVB Mach 007 0

21 Unflteed Phase Eo Accumulaton - Howeve esdence tme measuements ae not pefect We ae nteest hee n the component of the esdence tme measuement eo due to eos n the C fequency offset measuement Fo C Sync message ths eo s equal to the fequency offset measuement eo multpled by the esdence tme.e. Fo Cs though m the total phase eo s at the tme of the th Sync message s φ m m Note: must add to ths the petubaton tself (.e. contbuton fom C ). Howeve we ae manly nteested hee n the addtonal phase eo due to the effect of the petubaton at downsteam Cs Substtute nto the above the esult fo (slde (C ) and slde 3 (Cs > )); the esult s φ m ω ω m A ( e ) e e ω SAMSUNG Electoncs EEE 80. AVB Mach 007

22 SAMSUNG Electoncs EEE 80. AVB Mach 007 Unflteed Phase Eo Accumulaton - Pefomng the summaton poduces Ampltude of phase eo fequency esponse s obtaned by computng absolute value of the above ( ) ) ( ) ( m m m m e A e e e e e A e e e e A ω ω ω ω ω ω ω ω ω ω φ max m n m e A ω φ

23 SAMSUNG Electoncs EEE 80. AVB Mach Unflteed Phase Eo Accumulaton - 3 he above esult s expessed n tems of the ampltude of the snusodal fequency offset petubaton A appled at C Refeence [6] uses as nput a snusodal phase petubaton o convet fom a fequency petubaton to phase petubaton we note a fequency offset at C of magntude A esults n a phase offset at C of A. Substtutng n the above poduces fo cumulatve phase offset (due to the effect of the phase petubaton on downsteam Cs) he maxmum phase petubaton occus fo ω π ; the esult s hs coesponds to the geneal fom gven eale wth G 0 B and a max m n m e B ω φ ) ( max m m n B π φ

24 Unflteed Phase Eo Accumulaton - 4 Bloc dagams fo fequency offset and phase eo accumulaton Stage to (.e. GM s stage 0 and petubaton s appled at stage to ethe fequency N (z) o phase (z) ) Stages - > to (.e. GM s stage 0 and petubaton s appled at stage Φ (z) z N (z) b N (z) N -(z) b-bz - N (z) Φ - (z) Φ (z) Φ (z) N (z) z-tansfom of fequency at node N (z) z-tansfom of fequency at node (z) z-tansfom of phase at node b / ( b ) N ( ) N ( z ) z z N ( z ) Φ ( z ) (z) z-tansfom of phase at node b / N Φ ( b bz ) N ( z) ( z) ( z) Φ ( z) N ( z) SAMSUNG Electoncs EEE 80. AVB Mach 007 4

25 Unflteed Phase Eo Accumulaton - 4 Notaton b sub sub / sub 0.00 N n C numbe Petubaton appled at C M c cyx Z`_/D^a]Z / X\ _/ c`^ R ph..0 9 n ph n ph n3 ph n4 ph n5 ph n omega n SAMSUNG Electoncs EEE 80. AVB Mach 007 5

26 Unflteed Phase Eo Accumulaton - 5 Notaton b sub sub / sub 0.0 ph n C numbe Petubaton appled at C ph..0 8 n M c cyx Z`_/D^a]Z / X\ _/ c`^ R ph n ph n3 ph n4 ph n5 ph n omega n SAMSUNG Electoncs EEE 80. AVB Mach 007 6

27 Unflteed Phase Eo Accumulaton - 6 Notaton ph n C numbe Petubaton appled at C M c cyx Z`_/D^a]Z / X\ _/ c`^ R ph n ph n ph n3 ph n ph n5 ph n ph n8 b sub sub / sub omega n SAMSUNG Electoncs EEE 80. AVB Mach 007 7

28 Unflteed Phase Eo Accumulaton - 7 Notaton b sub sub / sub 0. ph n C numbe Petubaton appled at C ph n ph n M c cyx Z`_/D^a]Z / X\ _/ c`^ R ph n3 ph n4 ph n5 ph n omega n SAMSUNG Electoncs EEE 80. AVB Mach 007 8

29 Unflteed Phase Eo Accumulaton - 8 he above esult fo phase eo accumulaton ampltude coesponds to the quantty (outputdevaton testdevaton) of [6] t s also equal to esdencetme * (syntonzedate ) accumulated ove the nodes Essentally t s the amount the accumulated phase eo exceeds the ntal phase eo due to the petubaton Relaton between dscete and contnuous fequency of petubaton Dscete fequency ω and contnuous fequency Ω ae elated by equvalent samplng tme.e. fequency update nteval. f the peod of the petubaton s then ω Ω π / π /ω ω π coesponds to petubaton peod equal to twce the fequency update peod o ω coesponds to petubaton peod equal (appoxmately) to 3. tmes the fequency update peod o 3. SAMSUNG Electoncs EEE 80. AVB Mach 007 9

30 Unflteed Phase Eo Accumulaton - 9 Results fom [6] fo / 0.05 B 00 ns nd C afte C whee petubaton s appled (.e. node 3 n notaton hee; node 4 n notaton of [6]). 3. (ω ) sub /sub M X\/X^a]Z /Z / Xaac` Z^X ] / /_ 6D c / Z /c ] / `_/ ]Z /; / `c/a Z/ Y/_5;/ / / `c/ ω ) outputdevaton testdevaton ssuetme Fgue 6. Results fo (outputdevaton-testdevaton) usng Mathcad fle povded n [6]. hs quantty s the fequency offset at the fst node afte the node whee the petubaton s appled multpled by the deal esdence tme. he peod of the appled petubaton s 3.. SAMSUNG Electoncs EEE 80. AVB Mach

31 Unflteed Phase Eo Accumulaton - 0 Results fom [6] fo / 0.05 B 00 ns nd C afte C whee petubaton s appled (.e. node 3 n notaton hee; node 4 n notaton of [6]). (ω π) 6M X\/X^a]Z /Z /X aac` Z^X ] /:9/_ 6D c / Z /c ] /` _/ ]Z /; / `c/a Z/ Y/ _5;/ / / `c/ω π) sub /sub 0.05 outputdevaton testdevaton ssuetme Fgue 7. Results fo (outputdevaton-testdevaton) usng Mathcad fle povded n [6]. hs quantty s the fequency offset at the fst node afte the node whee the petubaton s appled multpled by the deal esdence tme. he peod of the appled petubaton s.. SAMSUNG Electoncs EEE 80. AVB Mach 007 3

32 Unflteed Phase Eo Accumulaton - 0 able of [6] lsted some dffeences between analyss thee and hee When able was pepaed compason was wth fequency offset accumulaton study hee (phase offset accumulaton study had not yet been done) Also compason used dffeent petubaton fequences SAMSUNG Electoncs EEE 80. AVB Mach 007 3

33 Unflteed Phase Eo Accumulaton - 0 Dffeences esolved by compang wth phase accumulaton study and usng same petubaton fequency able of [6] ndcates G 0 thee and / hee the latte s fo the fequency offset accumulaton; t s fo phase accumulaton n ageement wth [6] able of [6] ndcates wost case gan peang was obtaned fo petubaton peod of 3. tmes fequency update nteval and not tmes fequency update nteval Howeve usng Mathcad lstng suppled n [6] a lage outputdevaton testdevaton s found fo petubaton peod of tmes fequency update nteval»hs s maxmum and s n ageement wth esults obtaned hee Stated n [9] that dscepancy s due to compang dffeent quanttes n [6] vesus hee»hee we compaed outputdevaton testdevaton»[6] compaed outputdevaton / testdevaton and noted that dffeence s due to dffeent phases of dffeence sgnal (outputdevaton testdevaton) and test sgnal (testdevaton); n [6] these sgnals ae 90 degees out of phase SAMSUNG Electoncs EEE 80. AVB Mach

34 Wande oleance he phase accumulaton esults on the pevous sldes assume a 00 ns snusodal phase petubaton ampltude hs can be consdeed n the context of wande toleance Apply a snusodal phase wande at a C and eque that the syntonzaton and synchonzaton tanspot meet the espectve equements (e.g. ME tme synchonzaton) hs assumes that the system paametes (e.g. sync nteval fequency update nteval ae set appopately We would choose the syntonzaton algothm and the endpont flte specfcatons such that the applcaton tte wande and synchonzaton equements could be met when the snusodal petubaton s appled t s stated n [9] that the 00 ns ampltude fo the snusodal petubaton s abtay Would moe lely want to toleate 40 ns pea-to-pea (esultng fom phase measuement ganulaty combned wth beatng of oscllatos whose fequences ae close SAMSUNG Electoncs EEE 80. AVB Mach

35 Flteed Phase Eo Accumulaton - Note that the phase eo accumulaton esults obtaned above ae unflteed he levels would lely be educed by endpont flteng Fo example consde a fst-ode lnea dgtal flte wth an equvalent s tme constant H ( z) z he equvalent tme constant s seen to be s by notng that ths flte educes a step nput to /e 0.37 of ts value afte 0 steps.e. (0.9) and that 0 steps hee coesponds to s because 0. s o obtan the flteed fequency esponse Substtute z e ω n the above z-tansfom fo the flte Multply the unflteed phase eo fequency esponse on slde 3 (fst equaton on that slde) by ths flte fequency esponse he esult s on the next slde SAMSUNG Electoncs EEE 80. AVB Mach

36 Flteed Phase Eo Accumulaton - Compang ths wth the fgue on slde 7 the educton s seen to be appoxmately a facto of 0 b sub sub / sub phflt n phflt n phflt n 3 phflt n 4 phflt n 5 phflt.0 9 n 6 phflt n omega n SAMSUNG Electoncs EEE 80. AVB Mach

37 Splt Path Syntonzaton Scenao - Refeence [8] poposes a scheme that attempts to avod phase eo accumulaton n nodes subsequent to the C whee the snusodal phase petubaton s appled Use the fee-unnng node cloc fequences to measue esdence tmes Use these esdence tmes to compute the coected maste event tmestamps (tmestamp when Sync message leaves maste plus accumulated esdence tme) Use these coected maste event tmestamps to estmate fequency offset of each C elatve to maste Use the estmated fequency offset to compute esdence tme eo and accumulate n a sepaate feld of the Follow_Up message Use ths eo accumulaton to coect the synchonzed tme at the espectve node he next 3 sldes taen (.e. dectly coped) fom [8] llustate the method (the fst slde shows the cuent syntonzaton method; the second and thd sldes show the splt path scenao) SAMSUNG Electoncs EEE 80. AVB Mach

38 Splt Path Syntonzaton Scenao - X\ _/ c`^/r SAMSUNG Electoncs EEE 80. AVB Mach

39 Splt Path Syntonzaton Scenao - 3 X\ _/ c`^/r SAMSUNG Electoncs EEE 80. AVB Mach

40 Splt Path Syntonzaton Scenao - 4 X\ _/ c`^/r SAMSUNG Electoncs EEE 80. AVB Mach

41 SAMSUNG Electoncs EEE 80. AVB Mach Splt Path Syntonzaton Scenao - 4 Can analyze the splt path syntonzaton scenao n a manne analogous to the conventonal analyss Use the equaton fo μ on slde 8 to compute the measued fequency offset but now the ae fxed (fee-unnng) fequency offsets (except at C whee s a snusodal petubaton Expess ths equaton to fst ode n the ( ) ( ) ( ) ( ) ( ) μ

42 Splt Path Syntonzaton Scenao - 5 Next note that the fequency offsets at nodes othe than C ae fxed and theefoe the tems n the above summaton fo > vansh hen μ ( ) he total phase eo due to components at nodes though s μ ( ) ( ) We have omtted the petubaton tself at node because we ae nteested n the accumulaton ove and above ths he actual tme Sync message aves at C s m ) actual m0 ( he coected maste tme at C based on the fee-unnng clocs s m m ( 0 ) SAMSUNG Electoncs EEE 80. AVB Mach 007 4

43 Splt Path Syntonzaton Scenao - 6 Usng the measued fequency offset to coect the actual fequency offset n the above sum poduces m ( ) m0 ( ) ( ) ( ) Note that the fst summaton n the above equaton s zeo because the fequency offsets at nodes though do not vay n tme Omttng that tem and compang the above wth the actual tme the Sync message aves at C poduces fo the phase eo accumulaton φ ( ) ( ) nsetng a snusodal fequency vaaton ampltude A and elatng ths to the snusodal phase petubaton ampltude B though B At poduces ω φ B ( )( e ) e ω SAMSUNG Electoncs EEE 80. AVB Mach

44 Splt Path Syntonzaton Scenao - 7 hen the magntude of the phase eo accumulaton s φ B ( ) ( cosω) he maxmum ampltude occus at ω π.e. when the petubaton peod s twce the fequency adustment tme. he esult s φ B ( ) max he coespondng esult fo a C syntonzed usng the conventonal method s φ B max SAMSUNG Electoncs EEE 80. AVB Mach

45 Splt Path Syntonzaton Scenao - 8 he ato of the accumulaton facto fo the conventonal appoach to that of the splt path appoach s F ( ) We see that fo << the ato s close to. When s appecable compaed to the ato can be lage afte a suffcent numbe of hops Rato of Gowth factos F F F 3 F 4 F b sub / sub b 000 b b 0.0 b 0.05 b 0. C numbe SAMSUNG Electoncs EEE 80. AVB Mach

46 Conclusons - f << a vey lage numbe of hops s equed fo the effect of a fequency offset to esult n appecable fequency o phase offset accumulaton Fo ato of 0.00 the fequency offset afte 00 hops s 0.% of the appled fequency petubaton ampltude; the unflteed phase offset s 0. of the appled phase offset ampltude f s appecable compaed to the accumulaton s faste Fo ato of 0. the fequency offset accumulates to the level of the petubaton afte hops; afte 7 hops t s appoxmately half the level of the petubaton Fo ato of 0. the unflteed phase offset accumulaton s about twce the appled petubaton ampltude afte 7 hops Fo the splt path syntonzaton scheme the beneft s manly fo netwos wth s appecable compaed to and a suffcently lage numbe of hops SAMSUNG Electoncs EEE 80. AVB Mach

47 Conclusons - f t s decded that 80.AS netwos must toleate snusodal phase wande appled at a cloc consdeaton should be gven to the wande ampltude that must be toleated One ampltude to consde s 40 ns pea-to-pea due to phase measuement ganulaty and beatng of adacent oscllatos that ae close n fequency Phase eo accumulaton wll be educed by endpont flteng; ths should be accounted fo n consdeng ablty of systems to toleate snusodal wande SAMSUNG Electoncs EEE 80. AVB Mach

48 Refeences -. Chuc Hason Emal to P588 Reflecto Febuay Chuc Hason Emal to P588 Reflecto Febuay E. L. Vama and J. Wu Analyss of Jtte Accumulaton n a Chan of Dgtal Regeneatos Poceedngs of EEE Globecom Vol. pp U- Rec. G.85 he Contol of Jtte and Wande wthn the Optcal anspot Netwo U- Geneva Novembe 00 (Amendment June 00 Cogendum June 00). 5. EEE P588 M /D-A 7 Febuay 007 Daft Standad fo a Pecson Cloc Synchonzaton Potocol fo Netwoed Measuement and Contol Systems Daft D-A Febuay Chuc Hason Cascaded Gan Phenomena n EEE 588v anspaent Cloc Chans: an ntal Study contbuton dstbuted to EEE 588 and EEE 80. Febuay Geoffey M. Gane Analyss of Cloc Synchonzaton Appoaches fo Resdental Ethenet pesentaton to EEE 80.3 Resdental Ethenet SG San Jose Septembe Chuc Hason anspaent Cloc Gan Cascade: Splt Path Scenao contbuton dstbuted to EEE 80. Mach SAMSUNG Electoncs EEE 80. AVB Mach

49 Refeences - 9. Chuc Hason Emal to P588 and EEE 80. Reflectos Mach 007. SAMSUNG Electoncs EEE 80. AVB Mach