thewraith2008
Member
- Joined
- Nov 22, 2016
- Messages
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I have a DMR Capacity MAX network 'TIII (MOT)' I'm monitoring and experimenting with using some custom DSD code I've been working on.
Normally, the SLCO opcode been used is SLCO=2 but I've noticed that every so often (i.e after many hours - random?) I also see SLCO=14(unknown) and SLCO=15(Cap+) opcodes been used.
At first, I thought this was some error in the DSD code either for Hamming, CRC or possibly a memory corruption (overflow or something else).
But now I think this is possibly normal and part of how Capacity MAX works.
Has anyone seen this occurring on any Capacity MAX networks that they monitor?
Other info:
Seen on both CC and VC.
The input signal to DSD is good and no decode errors are occurring while these SLCOs (14, 15) are seen.
- The hamming codewords(x3) and the CRC are valid with no errors when seen.
The 28 bits(+crc) of the SLCO(14,15) are quite different from the bits used in the SLCO=2.
I doubt random bits have just flipped and that it has not affected the hamming and the CRC checks.
While multi bit errors can make a valid codeword again, the CRC would still detect such an error.
I have also seen these SLCOs appear when using DMRDecode or DSD+.
DSD+ does not show any reference to the SLCO=15 opcode that I can see. Maybe be selectively ignoring it?
I have captured an IQ of these SLCO=14, 15 and on replay I still see the SLCO again at same timestamp. (Not a random decode issue)
When seen, the SLCO 14,15 are seen for about a minute also with the SLCO=2. (e.g. 2,14,15,2,14,15....)
I have added some logging to the DSD code to see how frequent these occur and for what duration.
At this stage, they seem to occur quite randomly and at large intervals (1-13 hr)
Normally, the SLCO opcode been used is SLCO=2 but I've noticed that every so often (i.e after many hours - random?) I also see SLCO=14(unknown) and SLCO=15(Cap+) opcodes been used.
At first, I thought this was some error in the DSD code either for Hamming, CRC or possibly a memory corruption (overflow or something else).
But now I think this is possibly normal and part of how Capacity MAX works.
Has anyone seen this occurring on any Capacity MAX networks that they monitor?
Other info:
Seen on both CC and VC.
The input signal to DSD is good and no decode errors are occurring while these SLCOs (14, 15) are seen.
- The hamming codewords(x3) and the CRC are valid with no errors when seen.
The 28 bits(+crc) of the SLCO(14,15) are quite different from the bits used in the SLCO=2.
I doubt random bits have just flipped and that it has not affected the hamming and the CRC checks.
While multi bit errors can make a valid codeword again, the CRC would still detect such an error.
I have also seen these SLCOs appear when using DMRDecode or DSD+.
DSD+ does not show any reference to the SLCO=15 opcode that I can see. Maybe be selectively ignoring it?
I have captured an IQ of these SLCO=14, 15 and on replay I still see the SLCO again at same timestamp. (Not a random decode issue)
When seen, the SLCO 14,15 are seen for about a minute also with the SLCO=2. (e.g. 2,14,15,2,14,15....)
I have added some logging to the DSD code to see how frequent these occur and for what duration.
At this stage, they seem to occur quite randomly and at large intervals (1-13 hr)