[Discuss-gnuradio] RSSI Value

[pilla]

Hi,
i'm working on to calculate RSSI value via software. I'm using various methods
which give me the same result, but it depends on decimation value. The
behaviour is not linear changing decimation factor:
decimator        RSSI
28               220.18217468
30              354.19775391
32              562.27972412    *
34                3.6457119       *
36                5.1297369
..
62            225.86129761
64            282.75350952     *
66               1.99166834      *
68               2.27621746
..
128          141.76763916      *
130           1.34817326        *

there is a relationship but i don't understand. Could Someone explain that?
>From Gnuradio discussions I noticed that RSSI value can read from output AUX
ADCs by means of method "u.read_aux_adc(1,0)", but where has this value
calculated using RFX2400 / FLEX900 (on board)? I don't find it on schematic
block.
Is there a method to calculated RSSI on FPGA before DDC and Decimation Filter?

Thank you very much.

Giuseppe Pilla