OK I understand that. But is there any solution which permits to reset that growing propagation delay ? How to reset the flowgraph buffers without killing the application and restart it ? Is there any method that permits to purge and resync buffers of the flowgraph ?
Even if my application runs on a preempt_rt OS with a good calculation power, I'm not enough good in Linux tweaking to be sure that my application will not have a unusable delay after a long time. So I can accept to loose some time when I catch a PMT message of underflow to reset the sequencer and buffers. But how without killing apps ??
Best regards, Fabien, F4CTZ
---- Marcus Müller a écrit ----
Hello!
On 26.10.21 16:12, Fabien PELLET wrote: > > Why that propagation delay is always growing ? >
Exactly *becuause* your underflowing.
Your Receive side produces N samples – but too slow at some point, leading to your transmitter needing to "invent" an amount P of samples, because it simply has a fixed sample rate.
So, now, from the point of view of the transmitter's DAC, N+P sample periods have passed, whereas the receiver's ADC saw N sample periods. This repeats, and every P > 0. Therefore, the delay is always only growing.