I'm a bit confused. Your diagram TX->FIR->... ->Filesink
Indicates that TX is a source, whereas TX usually is an information sink in DSP. Maybe you want to fill us in about the type of block TX is? Greetings, Marcus On 16.10.2014 13:47, Mostafa Alizadeh wrote: > Hi Marcus, > > I tested again my problem with connecting a data file (file source) to the > fir filter and read the output with the one resulted from Matlab. The error > which appears due to the data precision is in acceptable order. > > However, when I directly connect my tx to the fir filter, it did something > strange after sometime which causes a great error with respect to the > Matlab one. > > *I think the problem is with my tx! I really confused!! I just wanna know > how could I identify the problem and how could I fix it? * > > My scheme: > > *[image: Inline image 1]* > > Best, > Mostafa > > On Wed, Oct 15, 2014 at 9:03 PM, Marcus Müller <marcus.muel...@ettus.com> > wrote: > >> Hello Mostafa, >> >> filtering is a inherently lossy operation: it's an operation that involves >> multiplication and addition of floating point numbers. >> Matlab internally uses double (float64) values, whereas GNU Radio, >> usually, uses single precision (float32) numbers for performance reasons. >> Now, without knowing what kind of signal you are filtering with what kind >> of taps you are using with what kind of GNU Radio filters and what Matlab >> functions, there's nothing to guess on how these differences occur. >> What I *can* say though is that I've never seen an item drop in GNU >> Radio's runtime, and we have strong tests against that. Now, it's entirely >> possible that any of our filter implementations might have bugs, but I kind >> of doubt that. It's most probably simply numeric accuracy that kills your >> samples. >> >> Greetings, >> Marcus >> >> >> >> On 15.10.2014 18:07, Mostafa Alizadeh wrote: >> >> Hi all, >> >> It seems this is a ridiculous question, however, I didn't find any solution >> for my problem. >> >> I have already a bunch of custom blocks connected to each other which play >> role as a transmitter (tx). I want to connect tx to a fir filter by using >> fir_filter_ccc block. I set the filter taps with specific ones. I also have >> this filter in Matlab. The output of the filter is connected to a sink file. >> >> When I see the output (tx) and filtering it by Matlab and comparing it with >> the output of the gnuradio filter, I see both of the following: >> >> 1) Both matlab and gnuradio filtered output, have little difference in a >> range of 0.01. (I'm using gr_complex data). >> >> 2) After a while, Matlab output and GNURadio's output will differ as high >> as 1000 in magnitude!! >> >> I guess, there is item drops in this filtering. I know, the probability of >> this event is so weak, anyway, item drop even can happen in GNURadio? >> >> Where is my problem? >> >> Best, >> Mostafa >> >> >> >> >> _______________________________________________ >> Discuss-gnuradio mailing >> listDiscuss-gnuradio@gnu.orghttps://lists.gnu.org/mailman/listinfo/discuss-gnuradio >> >> >> >> _______________________________________________ >> Discuss-gnuradio mailing list >> Discuss-gnuradio@gnu.org >> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >> >> > _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio