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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 :
! N4 F5 s0 G8 i8 H1 ?: I0 B               The doc spec write as below ,& V, }, S+ z8 d0 L# f
                   Frequency         Emission Level
: R6 L% }, ]' x3 M9 ^                2Mhz to 50Mhz    -30dbm/200khz
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             1. what's it mean ?
! ~, n3 E. i7 \' U7 ~0 R0 E& Y             2. How should I do when I measure spurious use Spectrum Analyzer ?8 I8 g! [& M6 P& i$ m) T+ S/ y2 w
            (ex: set RBW=200khz  and measured spurious below -30dbm is pass ?
5 v# z+ K8 V3 Y6 ]. c$ Z                   or others )1 h& n/ K* U% e7 m4 A- m
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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.7 N% n+ b/ g' ~& |5 E: W
I 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 :; o" @6 ]; h) r! k/ _# B( S! m: i+ Q
           Thanks your reply.
2 l' x( h: o0 l  S6 a/ g            To confirm again , ' {$ s, u" L% u( _; y
          1. It means when I measure use Spectrum Analyser I need to set + L+ ?; O* O, v7 V' `, z% h: S
              RBW=200Khz start=2Mhz stop=50Mhz,  D+ [6 N. K  J4 N; _9 T3 g
             if measured power level >-30dBm then it's fail , <-30dBm it's pass.8 e5 E, G' ?4 t( h1 A! |
              Right ?, ]7 X. C4 N& C* f+ c

  k0 }% t) {9 V5 U0 t7 ]          2. But my boss tell me it's need below -70dbm not -30dbm , I don't know why.
; g& g# q, k/ E1 R* Y6 l             If I transfer it to dbm/hz is -83dmb/hz ,it become more severe than -70dbm
- o* h. B9 F1 @4 |7 q; v8 ]             and unit also different.$ Y3 R0 W8 v, `) o2 H, Q
             I don't know which part is wrong ?# |# k3 e4 B$ K
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           Thanks.




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