Selectivity improvement solutions proposal for UmTRX

Alexander Chemeris alexander.chemeris at gmail.com
Sun Mar 18 17:13:51 UTC 2012


Hi Jean-Samuel and Andrey,

On Sun, Mar 18, 2012 at 18:25, Jean-Samuel Najnudel - BJT PARTNERS
SARL <jsn at bjtpartners.com> wrote:
> However, I really believe the preselector should remain on the UmTRX main
> PCB.
> If we want to connect the preselector as an external mezzanine board, it
> would cost us 5 extra SMA connectors (RX1in, RX1out, RX2in, RX2out, clock
> source), 2 RF switches before the superhet filtering (to still be able to
> have switched diversity), several GPIO (serial mixer control, RF switches
> control) and power supply.
> This is possible but it would really cost much more than keeping the
> preselector on the main PCB, especially as I believe, in practice, we will
> need almsot always this preselector, even not to pass the GSM spec but just
> to be able to get a reasonably narrow sampling bandwidth.
> I would really suggest to keep the preselector in the main PCB and
> populating or not the components (VCO/PLL, mixer and SAW IF).

Could we save on connectors if we use some RF side connector with many
pins? Nothing specific in mind, just thinking out loud.


-- 
Regards,
Alexander Chemeris.
CEO, Fairwaves LLC / ООО УмРадио
http://fairwaves.ru



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