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 :! H% C' M! o+ L$ \6 _5 Y; i* S
The doc spec write as below ,( {/ G- Y7 G& W" A( Z& Z* L8 J' z
Frequency Emission Level* s+ m8 M* Q& Y5 q" Y3 M: M
2Mhz to 50Mhz -30dbm/200khz ! v/ l. ]8 `8 Y% D2 } ; B& M* \! F- J2 @! ` 1. what's it mean ?) v" N0 d' o) Q1 ]" E5 G
2. How should I do when I measure spurious use Spectrum Analyzer ?9 J/ g( k @* b5 r
(ex: set RBW=200khz and measured spurious below -30dbm is pass ?) R6 j' P* X) K1 ~% ]
or others ) 1 j/ H0 O, K! Q: C 3 r8 `" X/ Z0 t+ m( H, ` 7 E6 u; ~: ~) ? 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. $ ^$ y" Y7 b$ x3 b/ m7 j6 U) M& [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 : / H& V8 x% _+ }8 W H Thanks your reply.$ `0 O+ j0 d" M: d1 I" ^
To confirm again , , G- z0 G. c8 j/ T# E 1. It means when I measure use Spectrum Analyser I need to set . L0 C6 L3 u: v) s+ c, D3 N8 J RBW=200Khz start=2Mhz stop=50Mhz, + S8 t4 }' S+ a: O if measured power level >-30dBm then it's fail , <-30dBm it's pass.1 W2 k& W6 L1 p/ i/ m1 {
Right ? / ?! W, c0 d0 s$ D3 |4 Z- d% @! i C. C9 |
2. But my boss tell me it's need below -70dbm not -30dbm , I don't know why. F# a9 ^2 j6 a U" O
If I transfer it to dbm/hz is -83dmb/hz ,it become more severe than -70dbm1 A2 d9 F0 l2 T! O* B
and unit also different. , s& J+ ]- N* Z1 q0 ~9 _ I don't know which part is wrong ? + b3 M. @6 \% }6 Q" O9 U) A5 n y' {7 }4 D
Thanks.