Re: dvbt2 transmitter can not be real-time with LimeSDR

You could try DVB-T2 configurations that use less CPU. Both smaller FFT size and lower bitrate help. For example try the following test flow graphs:

vv009-4kfft.grc 27.588664 Mbps

vv010-2kfft.grc 14.364704 Mbps

vv011-1kfft.grc 6.169662 Mbps

If your receiver allows it, you can also use smaller channel bandwidths such as 5, 6, or 7 MHz. The bitrate will be scaled accordingly.

The DVB-T2 bitrate calculator is here.

https://github.com/drmpeg/dtv-utils/blob/master/dvbt2rate.c

Ron

On 9/29/24 22:30, Ali G. Dezfuli wrote:

When I run dvbt2 transmitter examples from gr-dtv without any hardware, "Probe Rate" block in GRC shows 15e6 samples per second at the output of the Tx (which needs about 9 Msps to work in real-time.)
Next, I connected USRP B200mini, but it showed underruns.
Talking to the community, they said UHD is heavy and suggested other SDR modules like LimeSDR.
But the problem still exists using LimeSDR-USB!
I wonder if there is a way to make "LimeSDR Sink (TX)" catch up with other blocks.
Details:
HW: Orange Pi 5 plus (32GB)
OS: Ubuntu 22.04
GR: v3.10.11.0

Thanks!