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 :- O& y5 T6 T6 i; E: z1 U% i. n
The doc spec write as below , ; C7 X7 ~' `4 D T9 d3 ] Frequency Emission Level * V9 Y# t m3 p3 n: k' u8 t9 } 2Mhz to 50Mhz -30dbm/200khz 4 L4 w2 v& ^/ w. J% l2 D
0 Z0 F; W' h9 a6 i
1. what's it mean ? $ C8 h; I' P# b# m 2. How should I do when I measure spurious use Spectrum Analyzer ? ) B* S* ?% C" _- g/ ^ (ex: set RBW=200khz and measured spurious below -30dbm is pass ? ) c6 c X" g& R1 r. h A1 G or others ) " ^! }" U9 S5 j9 D' e+ D) b " p. Y4 r2 l+ o/ F 9 I b/ l2 ?; e) \& X, J 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.1 m( O/ p& Q3 g
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 :4 V$ v3 G) x7 |7 [. L
Thanks your reply. 4 z5 `/ V6 }2 f# U5 ]5 r' g) S* s To confirm again , , y7 z! b7 k5 M3 } | 1. It means when I measure use Spectrum Analyser I need to set 0 T" I* U0 x+ _2 U3 z RBW=200Khz start=2Mhz stop=50Mhz,2 k5 f7 o4 j) c) L' i8 K
if measured power level >-30dBm then it's fail , <-30dBm it's pass. : `; V' m S" \: n: W Right ? - R( S* u$ j7 m7 i4 g. m3 K a/ G; b0 c( Q7 s2 w+ K9 k! i: U3 A
2. But my boss tell me it's need below -70dbm not -30dbm , I don't know why./ f `5 X# c3 I$ E
If I transfer it to dbm/hz is -83dmb/hz ,it become more severe than -70dbm( y5 H, i- n$ {6 j: E; B! \: x
and unit also different. 1 X X# N3 Z0 t3 y3 T9 I* w I don't know which part is wrong ? 5 m9 p: t9 v% S5 @+ _3 n& Z3 }7 x) v, g1 p g. C4 y7 W- w* @0 H% U( i0 t
Thanks.