2012/8/8 Sylvain Munaut <246tnt@gmail.com>

Which spec is that exactly ?

Its about far-near problem (05.05 p.5.1), i.e. blocking by near mobile with high signal at only 600kHz offset.

Therefore, calculated that LO noise at 600kHz offset should be around -140dBc/Hz to keep nominal Rx sencitivity for wanted far mobile.

> Regarding the GSM 1800 version of the selectivity board, it will not be a
> problem to change the mixer and the filters. However, are you sure we will
> be able to get the correct matching if we only change the passives ? Are you
> sure we would not need to modify the PCB traces to get a good matching for a
> 1800 MHz version of the board ? What do you think ?

Unless I missed something fundamental, this board is only RX side right ?

Yes, it contain LNA, DivSwitch, down converter and IF filter for Rx path only.

Late I'll make band dependant boards with 1-2W TxPA and ceramic duplexer.

But, possible no reasons to do it, I don't sure yet.

To get any significant loss in RX due to mismatch, you need a very
large mismatch.

Yes.

Best regards,

Andrey Sviyazov.