標題: about dbm/200khz problem.. [打印本頁] 作者: super 時間: 2009-5-22 10:32 PM 標題: about dbm/200khz problem.. Dear all : / e) l- i& i( G7 l8 I+ E The doc spec write as below ," ~, U: T2 ?! L& R
Frequency Emission Level - I7 T3 j. w/ Q" E! m 2Mhz to 50Mhz -30dbm/200khz ) I+ ^, ?. @0 B# C
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1. what's it mean ? $ D! W: e8 a9 K H) r! J/ H1 j- q 2. How should I do when I measure spurious use Spectrum Analyzer ?1 {1 b9 O# l8 j+ Y# ?/ E" H- F- {
(ex: set RBW=200khz and measured spurious below -30dbm is pass ? 1 @# \. ~2 U% | c! S or others ) - o& Q- L0 H" A3 e' p) ]; L/ p/ E
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Thanks.作者: cqmyg5 時間: 2009-5-23 08:05 AM
I'm not an expert, I think "set RBW=200khz and measured spurious below -30dbm is pass" is correct. " z4 Q* Y2 e, QI know another spec: -40dBm/1MHz, that's to measure dBm per 100k(RBW=100k)., then sum(10), if below -40dBm is pass.作者: super 時間: 2009-5-24 07:41 PM
Dear sir : - i( l( R/ B# K( [+ ~. {9 p Thanks your reply.2 U3 ^ o5 H$ b4 N0 C
To confirm again , % f' B% `* C( I( m
1. It means when I measure use Spectrum Analyser I need to set & K* k( r5 [* t' \7 T3 J k RBW=200Khz start=2Mhz stop=50Mhz, ; d2 ~. F: Q) Y; \8 V if measured power level >-30dBm then it's fail , <-30dBm it's pass.6 i2 c8 [- R9 T4 }# g
Right ?; j5 E8 |, G( C3 U7 z
% R M8 h4 q1 q. L& ` 2. But my boss tell me it's need below -70dbm not -30dbm , I don't know why. 8 S4 Q. ~9 w y" [" R If I transfer it to dbm/hz is -83dmb/hz ,it become more severe than -70dbm 7 W( G Q7 k g( k* M' B and unit also different. ) i2 F2 y2 k! A' S1 C6 x0 J3 X I don't know which part is wrong ?: ?2 V7 f3 g5 K5 I