Question about codewords and LoRa symbols in "LoRa modem with LimeSDR"

General Discussion
1

In the extremely interesting LoRa modem with LimeSDR page it says,

Each codeword contains 4 [input bits]+RDD [error correcting] bits, and each output symbol contains SF bits (the spread factor). Therefore it takes SF codewords to produce every (4+RDD) symbols

For example, does this mean that with a spread factor of 7 and 1 redundant bit per 4 input bits, the 5-bit “codeword” (4 data bits + 1 error correcting bit) translates to seven 5-bit output codewords?

If so, how does one 5-bit input codeword translate to seven 5-bit output codewords?

I suspect I’m understanding this properly which is why I’m asking here.

Thanks in advance
Ben

2

This was put together by @joshblum nearly 10 years ago. I’m not sure if he gets forum notifications, but would be the best person to comment.