I’ve been trying out the new DVB firmware for the Lime mini and I’m experiencing a 25 second delay on the received signal on the Minitioune when streaming using IPTS. When using 1.30 Lime firmware I get about a 2.5 second delay.
Portsdown setyp:
Sym Rate 333
MOD DVB-S
FEC 7/8
FRQ 146.5
ENCODER IPTS
With such a long delay I’ve gone back to Lime version 1.30, has any seen this type of delay with the DVB firmware or is it finger problems on my part?
Phil
M0PIT
Lime DVB Firmware
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This forum is run by the BATC (British Amateur Television Club), it is service made freely available to all interested parties, please do not abuse this privilege.
Thank you
Re: Lime DVB Firmware
Hi Phil
Thanks for pointing this out. I had not realised that the delay was so long for DVB-S. The delay for DVB-S2 (333 kS 9/10 FEC)is about 6 seconds, so a lot more acceptable, although still longer that the normal firmware (1.30) delay of 2 seconds.
The LimeDVB firmware was really intended to allow higher SRs on the LimeSDR Mini, and at the higher SRs the delay reduces (10 seconds on 1MS 7/8 FEC DVB-S).
So, you can either stick with Firmware 1.30, or switch to DVB-S2, or both. And it's not finger trouble - I have just reproduced the problem on my test rig.
I will look at whether I can reduce the delay for DVB-S (this might be in the code that I can edit). By coincidence, I e-mailed the author of the LimeDVB firmware this morning about whether there was any chance of reducing the extra delay (the 6 seconds vs 2 seconds for DVB-S2) that is in the really clever code that he has written.
Dave, G8GKQ
Thanks for pointing this out. I had not realised that the delay was so long for DVB-S. The delay for DVB-S2 (333 kS 9/10 FEC)is about 6 seconds, so a lot more acceptable, although still longer that the normal firmware (1.30) delay of 2 seconds.
The LimeDVB firmware was really intended to allow higher SRs on the LimeSDR Mini, and at the higher SRs the delay reduces (10 seconds on 1MS 7/8 FEC DVB-S).
So, you can either stick with Firmware 1.30, or switch to DVB-S2, or both. And it's not finger trouble - I have just reproduced the problem on my test rig.
I will look at whether I can reduce the delay for DVB-S (this might be in the code that I can edit). By coincidence, I e-mailed the author of the LimeDVB firmware this morning about whether there was any chance of reducing the extra delay (the 6 seconds vs 2 seconds for DVB-S2) that is in the really clever code that he has written.
Dave, G8GKQ
Re: Lime DVB Firmware
Phil
I found some of the problem and have just issued a development release with a fix that reduces the delay that you reported from 25 seconds (unusable) to about 6 seconds (just usable). It only affects LimeDVB DVB-S transmissions, no others.
There is still about 4 seconds that I think can be pruned, but I think that is in the FPGA software, which is way beyond me, so I have asked Nats (who wrote that) to look at it.
If you want to try the development release, first update to the latest production version (202003280) and then try to update again. Press the "Dev Update" button.
Dave, G8GKQ
I found some of the problem and have just issued a development release with a fix that reduces the delay that you reported from 25 seconds (unusable) to about 6 seconds (just usable). It only affects LimeDVB DVB-S transmissions, no others.
There is still about 4 seconds that I think can be pruned, but I think that is in the FPGA software, which is way beyond me, so I have asked Nats (who wrote that) to look at it.
If you want to try the development release, first update to the latest production version (202003280) and then try to update again. Press the "Dev Update" button.
Dave, G8GKQ
Re: Lime DVB Firmware
Hi Dave,
Thanks for the prompt response and action, now running the your development release.
Phil, M0PIT
Thanks for the prompt response and action, now running the your development release.
Phil, M0PIT