Re: [Discuss-gnuradio] Need of delay=58 in the PSK Symbol Recovery Guided Tutorial

[Martin Braun]

On 22.05.2015 17:38, Francisco Albani wrote:
> Hi, I managed to successfully replicate the results of this tutorial:
> 
> https://gnuradio.org/redmine/projects/gnuradio/wiki/Guided_Tutorial_PSK_Demodulation
> 
> and, of course I understand the reason for a delay between the bits of
> the source and the receiver.
> 
> But then I was struck by this: considering that the 2-input QT GUI
> Time Sink consumes one sample of each at the same time and waits
> otherwise, wouldn't this act as an "involuntary" synchronizer for the
> bit streams?

The time sink will consume input streams synchronously, that's correct,
but in this example, we also want to make sure the actual content is
sync'd as well. So the delay block will insert some zeros before the
signal starts, shifting signal in time such that they become aligned in
the time sink.

M