[Tinyos-help] Noise and RX power

Daniel Andrade Costa Silva daniacs at dcc.ufmg.br
Mon Mar 7 20:09:08 PST 2005

Hi all... 

 reading the MPR-MIB manual, it says how to get the values of Battery and 
potency that come from ADC:

Vbatt = Vref × ADC_FS / ADC_Count;
Vrssi = Vbatt x ADC_Counts / 1024; and
RSSI(dBm) = -50 x Vrssi - 45.5; (I use the 915MHz freq)

that is, the RSSI value depends on the battery value (that's what I got 
from this). 

---> Can I just get the RSSI value of noise or signal not depending 
on the Battery value? On BMAC, how these values are handled (eg. when 
radioState == PRETX_STATE, when ADC data is already ready, it compares 
this data with the actual usSquelchVal value). Is there a formula to 
convert these values (like CC1K_SquelchInit) to dBm without getting data 
from ADC to measure voltage?? 

Almost forgot... what's the meaning of CC1K_SquelchBuffer (that is 0 on 
Tiny-OS 1.1.7)?

Since now,
Thanks a lot!!!

Daniel Andrade Costa Silva
Computer Science - UFMG - Brasil
daniacs at dcc.ufmg.br
ICQ: 15350463

"To err is human. To moo bovine"

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