On 03/29/2011 04:51 AM, James Jordan wrote: > Hi all I use xlating filter to retrieve the baseband signal and I use > such way the compute the samples > signal strengh like this: a = sqrt(i * i + q * q) (i and q means the > complex signal's real part and image part) > then compute the average signal strengh: rssi = (sum of all sample > strengh) / (sample count). With this way > all the channel's rssi result are the same(very close consider the > same) but actually they are not the same. > Is there any wrong in my method? I do not need the actual rssi value > but just need a way to distinguish the > channels' signal strengh. > RSSI = AVG(I*I + Q*Q) there shouldn't be a sqrt() term in there. Remember that the ADCs are sampling *voltage*, and power is proportional to the square of the voltage.
source---->complex-to-mag-squared---->single-pole-iir-filter Should do the trick -- Principal Investigator Shirleys Bay Radio Astronomy Consortium http://www.sbrac.org _______________________________________________ Discuss-gnuradio mailing list [email protected] http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
