we are working on big project with EFR32FG12 series RFSoC. It's very important for us to attenuate sample rate frequency by additional 15dB.
Is there any possibility in RAIL to :
- increase Target oversampling rate for more than max. 8
- change filter coefficents
With this we will get pure RF spectrum and full demands for our product. RF spectrum plot and efr32_radio_configurator_log.txt are attached.
The OSR at the Tx side cannot be ecplicitely set. The target OSR advanced parameters is Rx only.
The 1st quick thing you may try is decreasing the bandwidth on the PLL in Tx mode with the following advanced parameter. If this is already bottomed out we need to look elsewhere. (Top right control on below plot)
Your spectrum plot seems to have been taken with two RBW settings (I see a jump around 200 kHz from the carrier), can you tell me both?
thank you very much for your fast response. First RF noise step is from our spectrum analyser. PLL Tx bandwith is already @ 250kHz. We need to remove Fs ( 320 kHz sampling frequency) for 15dB in baseband. Do you upsample IF signal before modulation?
Tx symbol shaping is done at 8 x the symbol frequency at DC. This stream is than directly upsampled to the HFXO frequency (38.4 MHz by typcially) with an interpolator, there is no IF at the Tx side. This stream directly modulates the synthesizer.
Can you pls try disabling the shaping filter and see how the spurs change? I try and check beck more often for a quicker turnaround.