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 7 c% O& v$ f& E$ W5 A" u- `) ~( K9 h9 F# I7 S" f! l
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
7 h% T9 l6 y$ }
6 U4 O7 c; Q6 \ E; i
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
) H& _$ ?% Q$ a! M
Thanks.