HP 435B - Ge Neral Se Rvi Ce Inf Orm at Ion; Ca Libr Ato R

S ERV IC E S HEE T 2
(Cont' d )
s y ste m will n ot be deg r
ade d . M eas urin ga nd r eco rdin g do vol-
tages
a nd com
p a
rin g t h e m wi
t h t
h
e n o rm a l l e ve l s s h o wn on t h e
sc h e m at i cs m ay h e lp to i so l
ate
d
e
f
ect iv e co mp o n e n ts . R efe r to
Ge n e r a l Se rvi ce Info rm at i o n (in
Sect
i
o n VIII) wi t h r ega rd to
o p e r atio na l a mplifi er c ir
c ui ts
.
Th e w av ef o rm s a nd v o l tages
s
h o wn
on t
h
e sc h e m at i c a re n o rm a l
w h e n o p e r at in g und e r t h e f o ll o win g
co
ndi
t i o n s .
ΝΟΤΕ
To exhib i t t h e co rr ect wa v efo
rm
s
in t h e RA N GE
sw i tc h p os i t i o n s indi cate d, t h e p
owe
r
se n sor (as
pa r t of t h e m eas ur e m e n t s y ste
m ) mu st m eas ure
powe r f r o m -35 to +20 dBm in to
α 50 Ω l oad .
α . P O WER M ET ER A ND S EN SO R . Set the P owe r
Meter's
RAN
G
E
s wi tc h to t h e 1 mW p os i t i o n,
C
AL FA
C
T
OR sw i tc h to
100% a nd t h e rea r p an e l PO WER REF s wi tc h to
(ON) . Conn ect
t h e po w
e r se n so r to t h e P o w e r Meter's P O WER REF
O UTPUT
j ac
k .
b . P O WER ME T ER A ND
HP
M
OD EL 11683 Α R ANG E CA L I-
BR ATO R . Set t h e P o w er M ete r 's RAN
G
E
sw i tc h to t h e 1 mW
p
os
i
t
i o n
a nd C ALFA CT OR s wi tc h to 100%
ο . Set t
h
e R a n ge Ca li-
br ato r
's RAN GE s wi tc h to 1 mW, P O LARITY s wi
tc h to N OR -
MAL
a nd FUN C TI O N s wi tc h to S TANDBY
. Co nn ect t h e R a n ge
Ca libr
ato
r
to t h e P owe r M ete r wi t h t h epo w e r se n so
r ca bl e . Set t h e
R an ge
Ca
libr
ato r FUN C TI O N sw i tc h to C AL
I
BRATE .
F
irst Amplifier
To
tr o ubl es h oot
t
h
e hybrid o p er at i o n a l a mpli fie re ff ect
iv
e
ly, co
n -
s id e r t h e
co
mpl ete
a
mpli fie
r as s h o wn on t h e sc h e m at i
c
on
t h e
opp
os
i te f o ld o u t
an d t
h
e p owe r se n so r 's sc h e m at i c .
Th e bi as l eve l s m a yb eu
sed
m
ost e ff ecti v e ly to iso l ate t h epr
o bl e m
to t h e P o w er M ete r . If
t
h
e
d
o v o l tage at ΤΡ 1 i s co rr ect bu t t h
e ac
v o l tage i s in co rr ect,
α
d
e
f
ect iv e co mp o n e n t pr o ba blye xi
sts
in
t h e
po w e r se n so r b e f or e
t
h
e signal i s inpu t to t h e hyb r id a mpli fie r .
An ac v o l tage co upl e d w i t h
α p osit iv e v o l tage (=+3 Vd c) at A
4 U
1
pin 2 w o uld in d i cate α d ef
ect
i n
t
h
e p o w er se n so r 's hybrid a mpli-
fi er inpu t or t h
e
in te r co
nn ect ca bl e . If t h e v o l tage at pin 2 i s abou t
0 .0 Vd c, t h e d ef ect iv e co
mp
o
n e
n
t
i
s pr ob a bly in t h e P o w e r
Meter's
Fir st Amplifie r .
Α p os i t iv e v o l tage at
ΤΡ 1 indi cates t h e m a lfun ct i o n i s pr oba bly in
t h e P o w e r Meter's Fir st Ampli fie r .
ΝΟΤΕ
D o n ot o ve rl oo k t h
eposs i
b
ili
t
y
t h
at a problem can
ex i st in t h e A u to Ze r o c ir c ui
ts
s h
ow non Se rvi ce
Sh eet 3 .