Re: [Discuss-gnuradio] rssi questions

[Brian Padalino]

On 8/7/07, Zhuocheng Yang <address@hidden> wrote:
> Hi guys:
>
> I noticed that in the adc_interface, there are registers called rssi_0, 
> rssi_1, rssi_2, and rssi_3. All of which are 32 bits. However, according to 
> the header format:
> http://gnuradio.org/trac/browser/gnuradio/trunk/usrp/doc/inband-signaling-usb
> The rssi should be 6 bits. Do I just use the lower 6 bits?

According to the instantiation:
    
http://gnuradio.org/trac/browser/gnuradio/trunk/usrp/fpga/sdr_lib/adc_interface.v#L43

The lower 16 bits has the RSSI value, and the upper 16 bits has the
over-count value.

If you were to just use 6 bits of the RSSI value, I'd recommend the
MSBs and not the LSBs.

Is this really the RSSI - or should the RSSI actually be a function of
the amount of gain or attenuation in the RF stages?  I am sure it gets
pretty difficult calculating an estimate for the amount of power at
the antenna.

Should this value be an expression in dB of the received power?

Brian