VE7UWU/sdrangel
1
0
Fork 0
mirror of https://github.com/f4exb/sdrangel.git synced 2024-11-17 05:41:56 -05:00
Code Issues Projects Releases Wiki Activity

meh.

Browse Source
This commit is contained in:
John Greb 2015-03-24 11:00:38 +00:00
parent a05759e1b8
commit 6534d1dd4d
1 changed files with 3 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
plugins/channel/lora/lorabits.h
View File

@ -5,10 +5,9 @@
More spreading needs higher frequency resolution and longer time on air, increasing drift errors.
Want higher bandwidth when using more spreading, which needs more CPU and a better FFT.
Six bit Hamming can only correct drift errors. Need 7 or 8 bit FEC for QRM
Easier to use 5:4 FEC with Reed-Soloman messages.
Six bit Hamming can only correct long runs of drift errors when not using interleaving. Interleaving defeats the point of using Gray code and puts multiple bit errors into single FEC blocks. Hardware decoding uses RSSI to detect the symbols most likely to be damaged, so that individual bits can be repaired after de-interleaving.
Implicit Mode: explicit starts with a 4:8 block and has different whitening
Using Implicit Mode: explicit starts with a 4:8 block and seems to have a different whitening sequence.
*/
// Six bits per symbol, six chars per block
@ -39,7 +38,7 @@ short LoRaDemod::toGray(short num)
return (num >> 1) ^ num;
}
// ignore FEC, try to extract raw bits
// Ignore the FEC bits, just extract the data bits
void LoRaDemod::hamming6(char* c, int size)
{
int i;