Hi Daren and Fabian, Fabian: Daren is using cyclic transmission so starting from the moment when the Pluto hardware buffer is full it repeats the samples over and over again. I think that CPU load has nothing to do here since as I said, samples are not being calculated in a real time manner. Marcin
niedz., 5 cze 2022 o 11:14 Fabian Schwartau <fab...@opencode.eu> napisał(a): > Hi Diren, > > I am not exactly sure what your problem is. > What you should know: gnuradio does not inherently has any sample rate > (unlike Simulink for example). Each block receives samples, processes > them, and outputs the same number of samples as fast as it can (except > if the block is interpolating/decimating - which is not the case for you > LPF). Between the blocks are buffers, which buffer the samples until the > next block will process it. The sample rate you set in most blocks is > just to calculate stuff (like the filter response) based on other > frequency settings (like your cut-off frequency). One exception here is > for example your PlutoSDR Source/Sink - both will actually > provide/require the sample rate you specify. > So, as your LPF has an interpolation of 1, it does not interpolate and > will output the same number of samples it receives. Your vector source > will provide samples as fast as possible until some buffer is full and > it will then keep it full. > One problem might be that your CPU cannot keep up filtering the > 61.44MSPS, which is quite a bit. Try increasing the transition width of > the filter, which will reduce the filter order and thus the CPU load. > > Hope that helps, > Fabian > > Am 04.06.22 um 23:09 schrieb DİREN ERDEM AYDIN via GNU Radio, the Free & > Open-Source Toolkit for Software Radio: > > Hello All, > > > > I'm working with Adalm Pluto SDR, trying to transmit and receive a > > custom burst signal given in the figure. To create the signal I'm using > > a vector block that creates a pulse and then due to a low pass filter I > > can extract the desired waveform. Flowgraph is also added. > > > > As far as I know, input/output sample rates of connected blocks should > > be matched. However, I'm providing 10k fewer samples to LPF because of > > the high sample rate of pluto, 61.44 M. When I tried to increase the > > samples in the vector source to Mega ranges frequency response of the > > signal drops drastically. I have also tried to use interpolation in > > between vector block and LPF, but it doesn't work either. > > > > My question is the LPF block normalizes the input sample rate to 61.44 > > M? The whole system works OK but this thing stays unclear for me. Thank > you. > > > > Regards, > > Diren > > >
