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thanks for you reply
but there are some difference between mine and xinxin's.
we use zero IF,and use RFMD3100
when pcl=0,low channel and high channel fail at +/-400kHz,but middle channel pass.
i don't know why
need help
thanks
I think somewhere is a misunderstanding. RF3100 is a CDMA PA.
In CDMA, modulation spectrum is part of the ACPR test, and is measured at +/-885kHz in 800MHz band and at +/-1.25MHz in PCS band.
Give me more details about your configuration.
If you are using RF3110 check the voltage on pin 5 (VREG) to be 2.8V +/-100mV. Also try to put locally a decoupling cap on this pin (0.1uF).
I remember that 6255 has some modulation problems that were fixed by the new 6270. Check with Infineon for this issue
Peroformance degradation could be many reasons for ORFS modulation
1. ORFS within loop bandwidth: Noise within TX Pll, like PFD...
2. ORFS out loop bandwidth: VCO noise
3. Modulator impact, like sideband suppression...
4. Noise coming from Vcc going into TX loop.
5. PA deep saturation or compression region, but failure occurs as wideband(1.8MHz or less)
I think you first check the signals before PA , perhaps it already fail on ORFS , you can tune the capacitors between I & Q signals. it would improve a little on ORFS . wish you good luck.
What's the background sense of tweak ORFS Modulation by capacitor between
differential Q or I? Would it be different showing on suppression spectrum when
sending all '1' data to RFIC with the change of capacitors value?
Thanks!
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