Noise and Index DW1000

I’m attempting to implement NLOS strategy described in APS006 PART 3, but when I retrieve FP_INDEX and PP_INDEX I obtain strange values: FP_INDEX is about 48000 (very very strange) and PP_INDEX is about 750. I put 1 TX and 1 RX in LOS with a ranging distance of about 50cm, and theoretically those indeces should coincide up to a small number. Moreover, if I change range distance the indeces remain the same I described above. Instead, FP_AMPL and PP_AMPL values appear to be more coherent, but my intentions is to rely on the algorithm that uses indeces instead of amplitude values. How can I solve this problem?
P.S. Is there also a way to retrieve a measurement of noise due to radio/electrical waves, not due to NLOS/LOS scenarios?

Are you correctly decoding the FP_INDEX value? 48000 is around the value you should see if you’re reading the raw register value without decoding it correctly.
As detailed in the user manual the raw value is in units of 1/64 of a sample in order to give greater timing resolution. If you right shift the value by 6 bits to get the integer part of the index (rounded down) for the first path.

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Thank you so much, now it looks it works correctly :slight_smile: