Definitions for Abbreviations

Hi everyone,

I am pretty new to all this and was wondering if someone can help me out with some definitions. The first one is RXPACC. What does it stand for and what does it do?
The second one is the FP_INDEX. Based on the dataset that I have, the FP index given to me is decimal points, but what do those stand for.

Thank you!

  • DW1000 User Manual : page 97, field RXPACC => “Preamble Accumulation Count”, RX stands for reception.
  • DW1000UserManual: 103, field FP_INDEX => “First path index”

For someone new to decawave products, what I can recommend, is exploring the Product documentation section, it’s a mine of information, user guides, datasheets, user manuals, even if not fully read, they can serve as a dictionnary to ctrl+f keywords

RXPACC, Receive Preamble accumulation count, this is a measure of how long the received preamble sequence was. Beyond calculating the receive power levels I’m not sure how much use this will be for most systems.

Have you looked at the CIR (Channel impulse response) data? This is in effect a measure of the received signal over time. The First Path Index (FP_Index) is the location within this data that the chip thinks the receive signal started and represents the point used to generate the receive time stamp.
The chip tries to be clever and interpolate between samples which is why the value has a fractional component. Again this can be useful for some diagnostics but isn’t something you normally need to look at for basic ranging operations.

1 Like