Hi ,
I recently noticed that all modulator blocks like qam psk gmsk ... have one similar problem , they consume high percent of CPU even when i connect a throttle to output of those . they consume a certain amount of CPU time (17%) and it doesn't change when i set throttle to 1k 10k 100k or even 10ms in the other word throttle in output doesn't work at all . PLS see first attached pic .
After digging around in source codes i noticed a common problem of them are last stage of modulators when connected to pfb_arb_resampler_ccf , i tested Polyphase Arbitary Resampler just alone and it have exactly similar problem . PLS see second attached pic .
It doesn't make any difference if i remove the throttle block and connect flow graph to a sink hardware for limiting sample rate it eat cpu in any case . some thing is wrong with Polyphase Arbitary Resampler block .
Cheers .