Symmetricom SyncServer S100 User Manual page 48

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TIMING - Holdover TIMING - Holdover
Overview Overview
The Syn The SyncSe cServe
perio iod d of of ti time per
For ex exam For ampl ple: e: A A Syn
sk skys yscr crape apers rs oc occa casi sion onal ally ly bl bloc ock k si signa
ca caus usin ing g "g "gaps
as as a a st stra ratu tum m 1 1 NTP
The fa fact ctory The ory def
si sider der ex exte tendi
lowing ng con lowi condit dition
Th The e Sy Sync ncSer
n n
The e Syn Th SyncSe
n n
Th The e Har Hardwa
n n
Res Restor torin ing g an an In Input
n n
Pl Plea ease se no note te th the e Hol
se sele lect cted ed on on th the e
Also Also see see
Stratum Stratum
The Settings The Settings
The e us user er ca can n si simp Th
ti ting ng ei eith ther er fi fiel eld d ge gener
About About
Tim Time e Error
correct correct time, time, acc
gro grows. ws. The The Syn
th the e es esti tima mated
The The
Oscillator Type Oscillator Type
Inpu Input t Refere Reference
– – The
TCXO TCXO
n n
– – The
OCXO OCXO
n n
ov over er pe perfo
Rubidium Rubidium
n n
formance. formance.
Severa Sev eral l me meth thods
Ent nteri ering ng a a va valu lue e fo for r E
n n
Sl Slid idin ing g th the e gr gree een n ve vert rtic ical al ba bar r on on th the e
n n
Sli Slidi ding ng th the e on one e of of the
n n
In Depth In Depth
Before Before ente entering
Pag Page e 36 36 ..........................................................................
rface e
rver r us uses es hol holdov dover er to to co cont ntin inue ue op opera
me if if th the e In Input put Ref Refere erenc nces es be beco come
SyncSe cServ rver er in in a a do downt
gnals ls fro
aps" " th that at la last st se seve veral ral ho hours urs. . The
NTP se serv rver er du duri ring ng th thes ese e ga gaps ps. .
defau ault lt se sett ttin ings gs are are app approp
nding ng hol holdov dover er to to co cove ver r th the e lo long nges est t an anti tici cipat
ions s is is true: true:
Serve ver r is is th the e on only ly NTP NTP se serv rver er av avai aila labl ble e to to th the e NTP
cServ rver er on only ly ha has s on one e Hard Hardware
dware re Cl Cloc ock k is is th the e on only ly NTP
put Refe Referen rence ce woul would d ta take ke lo long nger er tha
Holdo dove ver r se sett ttin ings gs on on th this is pa page ge al also so af affe fect ct NTP
page. page.
NTP - Prefs NTP - Prefs
(o (on n pa page ge 13 133) 3). .
mply ly s s et et th the e nu numb mber er of of da days ys
nerate ates s an an eq equi uiva vale lent nt va valu lue e in in th the e ot other
: : Whe When n no no In Input put Ref Refere
Error
accumulat umulating ing
tim time e erro error r
Sync c Se Serve rver r ke keeps eps an an on ongoi
ted ti time me erro error r is is eq equal ual to to or or gre
af affe fect cts s the the rat rate e at at whi
nces s are are ava availa ilable ble. .
The standa standard rd temperat temperature-compe ure-compensate
The optiona optional l oven-c oven-compens ompensated
rforma rmanc nce e tha than n th the e TCXO TCXO. .
– – Th The e opt optio iona nal l rub rubid idiu ium m os osci cill llat ator or ha has s th the e be best st st stabi
ods are are av avai aila labl ble e fo for r the the us user er to to ad adju just st Hol
Holdover Limit Holdover Limit
the bl blac ack k sp spher heres es un under
ring hol holdov dover: er:
..........................................................................99 997-0
erati ting ng as as a a st strat ratum
me una unava vail ilabl able. e.
wntown own of offi fice ce bui build ldin ing g ge gets ts ti time
from m the the GPS GPS sa satel telli lite tes s as as th they ey mo
The Syn SyncS cServ erver er us uses es ho hold ldov over er to to co conti ntinue
ropria riate te for for mo most st si situ tuati ations ons. . Howe
pated ed "g "gap" ap" if if mo
NTP cl clie ient nts s . .
ware Clo Clock ck In Inpu put t Ref Refere
NTP as asso soc c ia iati tion on li list sted ed on on th the e
than n th the e ho hold ldov over er per
NTP if if
la last sts, s, or or sp spec ecif ify y a a
Holdover Holdover
her fi fiel eld. d.
erenc nces es are are av avai aila labl ble, e, th the e os osci cill llato
. . The The ty type pe of of os osci cill llato ator r af affec
going ng es esti tima mate te of of the the ti time me erro
greate ater r tha than n th the e us user- er-co conf nfig igure
which ch the the os osci cill llat ator or ac accu cumu
nsated d osci oscillator. llator.
ated osci oscillator llator is is more more stabl
Holdo dove ver r or or Ti Time
or or and cl clic ick k the and
Time Error Limit Time Error Limit
gr grap aph h le left ft or or ri righ ght. t.
Holdover Holdover
der or or
H oldover Limit Holdover Limit
um 1 1 NTP NTP se serve rver/p r/pee eer r for
me fro from m GPS. GPS. Surr Surroun oundi ding ng
move ve ac acros ross s th the e sk sky, y,
nue ope operat
Howeve ver, r, the the us user er sh shou ould ld co con- n-
more re tha than n on one e of of th the e fo fol- l-
erenc nce. e.
page. page.
NTP - Assoc NTP - Assoc
perio iod d in in day days. s.
O ve Override rride Behav Behavior ior is is
Time Error Limit Time Error Limit
ator r dri drifts fts awa away y fro from m the
fects ts ho how quic w quickl kly y ti time me err error
error. r. Hol Holdo dove ver r end ends s whe when n
ured d Ti Time me Erro Error r Li Limi mit. t.
mula late tes s ti time me erro error r whe when n no no
stable e and and offers offers better better hold-
abili lity ty an and d hol holdov dover er pe per- r-
me Erro Error r Li Limi mit: t:
the button. button.
SET SET
le left ft or or rig right ht. .
Time Error Limit Time Error Limit
7-0152 1520-0 0-03 3 Rev Rev. . A A
for a a
ratin ing g
. . Se Set- t-
the
or
hold-