ESI VideoBridge 2150, Service Manual

Page: 89 / 332

2 . 5 . 2
S i gnal L e ve l s
The t e s t s i g n a l v o l t a g e l e v e l i n i t i a l i z e s t o l V R M S ( l O O O mV ) when
i n s t r umen t powe r i s a ppl i e d . T h e te s t s i g n a l l e v e l ca n be c ha ng e d a t
a n y t i me t o m e e t
l e ve l re q u i r e s
te s t i n g requ i remen t s .
re- c a l i bra t i o n o f t h e
Howe ve r ,
t e s t
c ha n g i n g t e s t s i g na l
f i x t u re . V o l t a g e i s
programma b l e f r om 5 mV t o 1 5 0 0mV RMS i n I mV s t eps .
p rog ramma b l e f rom O . l mA t o 1 00mA i n O . l mA s t eps .
C u r r e n t i s
E xa mp l e :
Push
Se t the a mp l i tude o f t h e t e s t s i g na l to 1 0 0mV RMS .
Di splay
H Z =
1 0 0 0 . 0 ItD"=
1 0 0 "�
C U lt T
D I RECT
SETL=0 0 50 " S I HT G R = 0 5 0 lt S AYE=O l
AUTO B I AS
U F F
Commen t s
To a l l ow t he t e s t
s i g na l t i me t o
s ta b i l i z e a f te r a
s i g na l l e v e l c ha ng e ,
wa i t 2 00 m s be f o re
•
99 . 185 n F cs
. 000 1 0
D
i n i t i a t i n g a measu re-
•
men t e
It I LL I YDL TS
To op t i m i z e mea s u r e m e n t a c c u ra cy , c a re s h ou l d be take n w h e n s e l e c t i n g
t e s t s i g n a l l e ve l s . Mea su r i ng h i g h i mpeda n c e c ompone n t s a t ve ry l ow
te s t v o l t a g e s o r v e r y l ow i mpeda n c e s a t ve r y l ow c u r re n t l e ve l s ca n
ca u s e m e a s urements to be erra t i c due to a poor s i gnal-to-noi se ra tio .
The te s t l e ve l v s . i mp e d a n c e c ha r t s ( Ta b l e s 1 - 4 , 2 - 5 ) i n t h i s ma nu a l
a re t o b e used a s a n a i d t o de t e rm i n i n g t he o p t i mum te s t s i g n a l l eve l
a t a n o m i n a l f r e q u e n c y o f 1 k H z . d o n o t i n d i c a t e a b s o l u t e
i n s t rum e n t d u e t o the ove rw h e l m i ng n u m be r o f tes t
f r equen c i e s a va i la b l e .
e
/
s
/
i
2 - 5 0
2 1 5 0 / 2 1 6 0 5 /8 5
•