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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 :
0 [6 p; V% K6 @" I               The doc spec write as below ,+ O& S7 ~$ C( z' g
                   Frequency         Emission Level
5 r4 h$ Y. O8 N/ i  I                2Mhz to 50Mhz    -30dbm/200khz " ~) k$ e" D: I
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             1. what's it mean ?
) N$ h& R) `: W# g+ ?1 O2 J8 T& n             2. How should I do when I measure spurious use Spectrum Analyzer ?5 m/ Z4 v# J* H- {) b! `
            (ex: set RBW=200khz  and measured spurious below -30dbm is pass ?
! i; v. k8 x3 X# q) x$ R                   or others )
# w- r0 H* {: P$ G1 N
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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.
' w- C) z' S9 R& FI 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 :
* o7 r9 Z! K# O+ c           Thanks your reply.1 r1 \7 X" E7 b) P
            To confirm again ,
0 R: k9 Q) q& O8 a% E& i          1. It means when I measure use Spectrum Analyser I need to set 4 U4 _' a% I  }9 X+ ^; u9 a
              RBW=200Khz start=2Mhz stop=50Mhz,
  N! O1 ]8 P: A  \/ L( g# o             if measured power level >-30dBm then it's fail , <-30dBm it's pass.9 [4 s/ R6 v) C, ^9 j
              Right ?6 \% x7 e/ a, A* Q2 m* M+ [) s

" g% X4 j* e. }) [9 [" ~% v9 `* D4 V          2. But my boss tell me it's need below -70dbm not -30dbm , I don't know why.& {5 a* z) B/ K3 p
             If I transfer it to dbm/hz is -83dmb/hz ,it become more severe than -70dbm
9 Z. }/ ?3 z: l, V# Z2 N             and unit also different.# @+ J" S! M' k  s3 a; L7 a
             I don't know which part is wrong ?7 U# M1 O; ?" i/ @0 Z# Y" Y8 R

7 j" d! h3 _0 b" M& C           Thanks.




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