HP 435B - 5-8. Power Meter Adjustments with 50Ω Power Sensor

Ad j u st m e n ts

M od e l 435
Β
AD JU ST MEN TS
5-8 . P O WER ME T ER AD JU ST
MEN TS W IT H 50 Ω P OWER S
EN
SO
R
REFEREN C E :

Se rvi ce Sh eets 2 a nd 3 .
DE SC RIPTI O N :

1 .

Th e B a l an ce co n t ro l i s ce n te r e d to
r
e m
o v e t h e d o o ff set in t r odu ce d by t
h e Au to
Z e ro c ir c ui t .
5-8
N OT E S
T hi s ad j u st m e n t s hould only be pe
r fo rm e d w h e n t h e HP M od e
l
11683 ΑR an ge Ca li b r ato r i s n ot available .
I f t he a d ju st m e n ts a r e to be co
n s id e r e d v a lid, t he P owe
r
M
ete r
mu st ha v e α ha l f h our wa
rmu p a nd t h e lin e voltage mu st be
w i t hin +5 to -10% ο ofn o min a l .
2 .

Th e D C O ff set co n t r o l re m o v es a
ny d o v o l tage in tro du ce d by t
h
e
D
C
Amplifi er .
3 . Th e C AL ADJ co n tr o l i s u se
d
to set α
l e v e l of +1 .00 Vd c at t h e
r
ea
r pa n e l
RE CO RDERO UTPUT j ac k w
i
t
h
α
full sca l e inpu t .
4 .

Th e M ete r co n tr o l sets t h e m ete
r r
ea
ding to full sca l e w h e n t
h
e
RE CO RDER
O
UTPUT l e v e l is +1 .00 Vd c .
5 .

Th e Au to Z er o O ff set ad j u st m e n t r e m o v es a
ny d o vo l tage in tr o du ce d by t
h
e
Au to
Z er o c ir c ui ts wh e n t h e ZER O s wi tc
h
i s pr esse
d .
6 .

Th e B a l a n ceco n tr o l ce n te rs t
h
e
Au to Z
e
ro c ir c ui ts o u t pu t v o l tage r a
n ge . Th e Au to
Z e r o o u t pu t i s f o r ce d to i ts
n egat iv e e x tre m e a nd t h e B a l a n ce co
n tr o l sets t h e
RE CO RDERO UTPUT
v o l
tage
b e l o w ce n te r - r a n ge (+1 .00 Vd c)
by o n e- ha lf t h e
tota l ra n ge .
HP
435 Β
P
O WER ME
TER
(SID E
P
A NEL)
RE
CO
RD ER
O
UTPUT
(RE AR P A NEL)
DIGITA L VO L TMETER
α
P O WER .

INPUT
S EN SO R

L
F igure 5-4 .
Power M eter A d j u stme n t Set up wit h 50 Ω P ower Se
n sor
E Q UIPMENT :

Dig i ta l V o l t m ete r . . . .
. . . . . . . . . . HP 3455A
P owe r Se n so r

. . . . . . . . . . . . . . . . . . HP 8481 Α / Η or 8482 Α / Η
PR OC EDURE :

1 .

Set t h e LINE s wi tc h to O
FF, w a i t α f e w seco nd s, a nd a d j u st t h e
m
ec
h
a
ni ca l m ete r
z e r o co n t r o l f o r α m ete
r r ea din g of ze r o .
2 .

Set t h e DVM RAN G E sw itc
h to 1 Vd c .
3 .

Set t h e P o w e r M ete
r
C
AL FA CT O R s wi tc h to 100% .
4 .

R e m ov e
t
h e ri g
h
t si
d
e
co v e r o f t h e P o w e r M ete r a nd co nn ect t
h e e quipm e n t as
s h o wn in
Fi g ur
e
5-4 .