On Mon, Oct 8, 2012 at 8:24 AM, Maicon Kist <[email protected]> wrote: > Hi list, > > I'm trying to recover a sound after passing it by a FFT and a IFFT. The > problem is that after the IFFT (to recover the original sound) and sending > it to the audio sink, I hear only wheezings. > > Attached to this email is the system that I created using the GNU Radio > Companion tool. > > Do your guys have any suggestion to recover the sound correctly? I think > that maybe is something with the sample frequency. > > Thanks. > > abc
There are two things to watch out for here. First, you made the classic mistake of using a throttle and a hardware block in the same flowgraph. The audio sink you have is the block that will do your sample rate control. You do NOT need a throttle block. It's not even that the throttle is unnecessary, but it will screw up your program. You have two clocks now competing for flow control. The throttle block is just a very poor approximation of a flow control based on the CPU and timers. Second, you might want to specify the device in the audio sink. By default, it's likely that you are using the ASLA sink, which provides no sample rate conversion. At 48 kHz, you might be ok. If you use pulseaudio (in Ubuntu, this is available by default now), for the 'Device name' parameter in the audio sink's options, you can use 'pulse.' Recreating your graph on my machine with these two changes worked fine. Tom _______________________________________________ Discuss-gnuradio mailing list [email protected] https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
