DCS Ch700 low PCL modulation spectrum degradation

wilsonchen

I met a problem that low PCL 15 with ORFS modulation worse than high PCL0.
I found TXVCO supply noise@ch700 also get different noise spectrum at PCL=0 and 15 where PCL0 having higher peak at center ch700 but better dBc number at 400KHz/600KHz than PCL=15.
I doubt different PCL brings different VCO load thus I get different ORFS modulation performance.
Can anybody have similiar experience or any clue ??
Thanks!!

yellowtoot

ORFS是什么东东呀?

HWRD

<P>Hi <b><FONT color=#000066>wilsonchen</FONT></b></P><P>Different PCL cause different power consumption,so the noise from power supply is different.so maybe large capacitor is need in your some component's voltage pin.</P><P>Hi <b><FONT color=#000066>yellowtoot</FONT></b> </P><P>ORFS:Output RF Spectrum </P>

RF110

Hi HWRD你这四年工夫可是炉火纯青啊

wilsonchen

<P>Hi HWRD,</P><P>Thank You. </P><P>But My case is that TXVCO noise is the only noisy one, while others, like RFVCO/IFVCO VCC are all clean relatively. All VCCs comes from external LDO output. And after layout check, no interference comes into TXVCO VCC trace, so what I believe more is that noise contributor is RFIC leaky path.</P><P>Regards,</P><P>And </P>[br]<p align=right><font color=red>+3 RD币</font></p>

BOBLUE

<P>D:\WORK\经验\阻抗匹配\123.bmp</P><P>可以使用这种软件来算呀</P>[em01]