LMS RX PLL questions

Sylvain Munaut 246tnt at gmail.com
Thu Feb 7 21:59:13 UTC 2013


Hi Ricardas,


Thanks for the quick answer. A couple of followup questions :


> You should see 2xLO, 4xLO ... as well.

Oh really ? Mmm, I couldn't see those. I guess they're much lower than
the odd harmonics and were buried in the noise floor.


> On the TX side these can be
> reduced by RF filter/duplexer. RX LPF will filter them out on the RX side.

Yes, I know how to get rid of them. Unfortunately designing a front
end that can programmably filter those for the whole range of the LMS
(like in a broadband SDR), it's not easy :p

So I was wondering if you had any data on the typical / worst case
values for those so I can know exactly how good a pre-filtering I need
to have on the input.


Cheers,

    Sylvain




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