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?