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F
4.9
STANDARDIZING
IHE
5228
AGAINST WWV
Sect.
fV
Page
5
4.IO
SIANDARDIZING THE 5228 AGAINST
'
.
-
I-
I.OCII'
FREQUENCY
STANDARO
The accuracy oI
the 100-kc crystal
is
10
parts per
;ixj;;;.
.001
percent, ard in general
no
adiustment
*liil-u n"""""i.y.
To maintain the
best possible
;";;;;;.
the 10d'kc standard rrequencv should
be
cheit<ed
weetrty
against
WWV
or
a
primary
[requen(']'
"i*a.ra.
,nd
iti"""""".y,
adjust
to bring exactly
;;i*il;".y.
The
typical
degree
of adjustment that
mav
be required to bring exactly
on
frequency
is
ir.rir"."
o.or
and 0.
1
cyile.
Consequently' unless
it
" "*iu.nrt
standard frequency
and
the
method
oi
ao"r"ri-n
have
great
enough
accuracy
ard
res(:'Jution'
a"'"lt
",i"-pt
ailustmeni
of
the
100-kc
oscilhtor'
The
lollowing
paragraphs
give two procedures.Ior
;;;p;";irs ;;a
ra5
r"iing
tl,u
1oo-kc
internaL standard
ir"o'u"n.r]
Tne
first
ard ttrost accurate metlod
beals
, il.rn"'^i.
ot th(' 100-kc standard output from
the
Sjig;,th
one
oI the standard frequetrcies broadcast
bv WWV and
requires
i
communications
recelvor'
ii"
,o.ord
mcthod
is for
usc whcn
the l)roadc'rst
i;ilwwn
is
not obtirinable and requires a Iocal
;;l;;".,
or
secondarv frcquettcv standard
i'tnd
xn
bscilloscope
ils the cumpalrson dcvi('t,'
Reier
to Figure 4-2
and
proceed as Iollorvs:
a.
Tuin
on
the
5228 and
allow to warm
up
for
30
m
inutes'
b.
Set
the
TIME UNIT selector to
100
KC'
c.
Connect
the
STD.
OUTPUT
conrector
on
the
rear
-
otme
instrument to harmonic generator such
as
a
crysta1 diode.
d.
Loosely
couple
tie
output
oI the
crystal
diode to
-'
tt
" ""tlnn"
oI
a
communication
receiver that is
tuneo
lo
one
of
the
f]'equencies
oI radio station
wwv'
e.
Adiust
C202 and
C203 Iocated on
the
chlssis neJr
''
tftl
fOO-f."
crlstal
until
a
zero-beat
is
obtained'
In most
cases
only
a
slight adjustmerrt
will
be
ncces-
;;;;,-iliii;rp";ito
rs
lhou ld be adjusted an
oquirl
amount
Ior b;st stability.
As
a
zero-bcat is
ap-
p""".f,"a,
WWV's
400
cycle audio tone
wiII
begin
io *oUUf", until
at exact
zero-beat the tone
will
be
"onsl"nt-'ff
an
audible
zero-beat
is
not
readily
ob-
tr-lr",i"
i"
'S' Meter
on
the receiver
can
be
used
tc)
obtain
a
visual
indication.
f.
U
necessary,
adj
ust coupling
wire
to-t}Ie
antenna
'
lor
tooaeJt
reit;
disconnect coupling wire
to
verijy
bcat.
Reler to Figure 4-3
and
proceed as follows:
a.
Turn
on
the 5228
and
a1low
to warm
up
for
30
minutes.
b,
Set
the
TIME UNIT selector to
100
KC'
c.
Connect
the
STD.
OUTPUT connector
on the
"'
;;;;;
th"
instrument to
the
vertical amplilier
un
"n"o""iir""ope;
conDect
the
1OO-kc
output
from
"'fi"q""*V
"trrdard
to the horizontal amplifier'
d.
Adiust the gain of the oscilloscope amplrfiers
-
i" hri^i,
a
"large
clear picture
similal
to
that
illustr'ated.
e.
Note
the rate of movement oI the oscilloscope
-"
;.t,;.;.
lI
il
moves at
the rate of
1
rel olution
r""
J".orJ it," tuo
frequencies
di-ffer
by one
cycle'
'n
i ."*"
"t
the
rate
of
1
.revolution
per ten
seconds
thc
difference is
0.
1
cycle'
et( '
f.
Adiust
C202
.-rnd
C203
located on the chassis
-'
;;;;
ure 100-kc
('rl'stll
until the pattern is sta-
tionarir.-
in-Lost
cases
only a
slight adjustnrent
will
L"'*"'"r"r.r,
botl
capacitors should be adjusted
an
equal amount
for
l)est
stabllitY'
4.I
I
TROUBLE
ISOLATION
Before removing
a
faulty instrument
from its
cabinet'
if-r"
f"fi"*itg
"".ies
oi
checks should be
per{ormed'
it i" pro""iutu
will
save
tinre
and
in
most
cases
i-"oirti tir"
trouble
to
a
particular portion of
the
cir-
"rii.-in"-""r,
externailcst
equipment
lequired for
;;i;'";;i;"
ot
".t
e.tt
is
.rn
oscillator that will provide
a
100
cPs. 10-voIt rnrs
output'
Al-I
tests should
be
porformed in the
sequence
given'
iii" i" irrp..ttrt
since
each
check
is
based on
au
previous checks giving tlormal indications'
when
a
tube
is listed
as
a
possible cause oI
trouble'
tne-asiociatea circuits
should
also be checked'
In
,.."n,
a^""t
tube replacement
wiII
eljminate
the
t.orble.
but
il
thls
does not
work,
it will
be
ne(es-
sary to
check
the associated components'
Refer to t}Ie appropriate Adiustment Sections of
this
manuat
tor
aii-adjustment procedures listed in
the
tabIe.
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