I'm writing a block that always outputs the same number of items as it gets in.
The block is doing FFT on a fixed length vector, so I always need nfft samples in and nfft samples out. I've achieved this (I think) by using: set_min_noutput_items(nfft) and set_max_noutput_items(nfft). However, when I increase nfft to 8192, I get a message about not enough buffer space. I tested various things and ended up calling
set_min_output_buffer(2*nfft) as just nfft wasn't enough. It all seems to work nicely, except that the rx_time tags are screwed up -- I get a nearly random offset in the beginning, even though there are no dropped packets on the USRP.
Is this a bug or a feature? What is the correct way to increase the value of noutput_items without breaking rx_time tags?