Hi Ron, Thank you for the advice, it's working now! I'll start to construct the loopback version.
Cheers, Tibor Herman Tibor Ron Economos <w...@comcast.net> ezt írta (időpont: 2022. febr. 10., Cs, 12:27): > You just have to match the parameters between the transmit and receive > flow graphs. The only difference is that the transmitter is using 64QAM and > the receiver is using 16QAM. > > So you can either change the transmitter to 16QAM or change the receiver > to 64QAM. > > You should add a throttle block to the transmitter (right before the file > sink will work). > > Since you're not transmitting over the air, the sample rate doesn't matter > if you're just creating a baseband file and playing it later. > > However, if you want to play the output stream in real-time, the sample > rate and bitrate of the Transport Stream do matter. Also, the performance > of the computer running the receiver flow graph has to be sufficient for > real-time. That's why the receive flow graph is configured for 16QAM as > most 4 core CPUs can support that bitrate. > > Ron > On 2/10/22 02:59, Herman Tibor wrote: > > Hi everyone, > > I'd like to teach students about OFDM modulation and I'd like to use > Gnuradio for the purpose. I'm trying to create a baseband signal with the > dvbt_tx_8k.grc project and decode it with the dvbt_rx_8k.grc project. The > problem is that the rx project cannot decode the baseband signal created > with the tx project. Has anyone tried this before? What am I missing? Do I > need to set something differently in the RX project compared to the > default? > > Is it possible to do it without actually transmitting the baseband signal? > I would think so. But then what is the sample rate? The variable is only > used in the UHD: USRP sink block, which I'd like to skip. > > I know I can download a sample baseband file, which works and I can see it > is generated, because the SNR is basically infinite. But I'd like to go > further and demonstrate with a longer video and possibly loop back the tx > to rx to modify the signal on the fly and finally play the stream in vlc. > > Thanks, > Tibor > > Herman Tibor > >
