Re: [Discuss-gnuradio] gr.firdes_hilbert () usage

[Chuck Swiger]

At 10:44 AM 11/25/2004 -0800, you wrote:

> On the Tx side, there's also the Weaver method.  We use it in the the
> ATSC Tx code.  There are two very small blocks that would need to be
> ported, GrWeaverModHead and GrWeaverModTail.  The unported versions
> are in CVS: gnuradio-core/src/lib/general

OK - I'll have to look at the Weaver methods.

I think what's happening is that: gr.firdes_hilbert taps in 
gr.fir_filter_fff is also
acting as a high pass filter, with a cutoff about 2% of the sampling rate 
(at 8e6 rate
it's down .7 at about 170Khz) so the mixer RF w(sig)+w(lo) gets thru and 
cancels
out in the summer, but the audio w(sig)-w(lo) gets blocked by hilbert, and thus
the unwanted sideband does not get canceled out in the summer.

--Chuck