[Tinyos-help] Query about the application"High Frequency RSSI Sampling Application"!

Philip Levis pal at cs.stanford.edu
Tue Feb 26 11:08:16 PST 2008


On Feb 26, 2008, at 2:35 AM, Ruoshui Liu wrote:

> Dear all,
>
> I saw an application called "High Frequency RSSI Sampling  
> Application" written by Phil Levis on the webhttp://docs.tinyos.net/ 
> index.php/ 
> TinyOS_2.x_index_of_contributed_code#High_Frequency_RSSI_Sampling_Appl 
> ication. I have a query about the purpose of writing this  
> application for measuring CC2420 RSSI readings. Is the RSSI value  
> returned from the RSSI field unreliable? If it is reliable for  
> research measurement, what is the point for writing another  
> programme to retrieve RSSI value?
>
> I also tried to read the RSSI register value, and compare it with  
> the values obtained from RSSI field. I found they were different,  
> could anyone help me with the explanation for this deviation please?
>

Read the CC2420 data sheet on how the RSSI register is filled. If you  
read it at different times, you can get different values. After all,  
the RF energy in the environment may have changed. That's one of the  
major reasons why wireless is hard.

Phil


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