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.