to understand GNURadio and the SRD world step by step, I tried to realize a first flowgraph to simulate a DSB modulator/demodulator. The signal is an audio file rec by the audio sink block at 32000 Sa/s. The USRP (N210) is the transmitter and the RTL (NESDR Mini 2+) is the receiver. I can't get it to work. Here are the figures of the flowgraph and the resulting prompt after starting it.
Please, notice me about my errors. Thanks
The sample rate of your UHD sink (1.28 Msps) and File Source (32 ksps) are not equal. You have to upsample 32 ksps to appropriate for N210 sample rate and configure uhd sink block to this rate.
N210 has a fixed clock of digital-to-analog converter (DAC) at 100 MHz. The DAC must be fed with this rate. To achieve this rate, in N210 there is interpolator, which upsample the input. The interpolation factor is from 1 to 512. For example, if the sample rate of uhd sink block is choosen 200 ksps, the interpolation factor will be 500. By default radio will automaticaly adjust interpolation factor.
You can add upsampler by 10, so sample rate from 32 ksps becomes 320 ksps. The sample rate of UHD Sink must be confugured to be 320 ksps.
