Re: [Discuss-gnuradio] /gnuradio-examples/python/digital/transmit_path.py and bitrate Question?

[Eric Blossom]

On Thu, Mar 19, 2009 at 02:28:08PM -0400, w w wrote:
> What's confusing for me is that I see the bitrate variable (it seems to have
> a profound importantance) but it looks to me like it never gets assigned to
> a block.   The following is line 119 from transmit_path.py.  In my mind the
> function of lines 119-121,  is to assign/derive values for bitrate, interp
> and SPS from pick_tx_bitrate.....Is this correct?   Of course it looks
> like bitrate stays the same unless it goes above 4 mbs.
> I don't see where the bitrate is being assigned  to either the
> packet transmitter or the modulator (which seems to me the most logical
> place to use bitrate).   I see where interpolation is being set for the usrp
> and I also see where sample per symbol is being used in various places.

> With my mind looking from all angles, the only thing I come up with is that
> interpolation is being used to control bitrate...but that don't make
> sense.

Why not?  This is a _software_ radio.  Everything scales with the
sample rate, and the interpolation value sets the complex baseband
sample rate.

Eric