On Tuesday 14 February 2006 00:13, Robert McGwier wrote:
> Thanks for your input. I am pretty ignorant about these FM standards
[snip]
> not have hiss that is irritating. But the COMPOSITE signal is what is
> FM modulated but I bet they do not preemphasize the composite signal.
> They might do pr
All:
I did deemphasis on Left and Right and checked it in just now. It is
much better now. Thanks for the links to the RDS stuff. I will take a
look.
THANKS it already sounds much better.
Bob
al davis wrote:
On Tuesday 14 February 2006 00:13, Robert McGwier wrote:
But the COMPOSIT
On Tuesday 14 February 2006 00:13, Robert McGwier wrote:
> But the COMPOSITE signal is what is
> FM modulated but I bet they do not preemphasize the composite
> signal. They might do preemphasis on the L+R baseband signal
> as Matt suggests but I just don't know about the others. I
> am trying to
Here is a link to the RBDS standard:
ftp://ftp.rds.org.uk/pub/acrobat/rbds1998.pdf
And another link to the digital AM radio standard:
http://www.ibiquity.com/technology/pdf/Waveforms_AM.pdf
On Tue, 14 Feb 2006, Robert McGwier wrote:
> Al, Matt:
>
> Thanks for your input. I am pretty ignora
Al, Matt:
Thanks for your input. I am pretty ignorant about these FM standards
and basically I googled my way to a reasonable spec, drew the flow
graph and coded it. The stereo demux was definitely not working with
DEemphasis applied to the composite signal. And it was clear why. The
tap
On Monday 13 February 2006 20:06, Matt Ettus wrote:
> I seem to remember that the preemphasis on stereo signals is
> not performed on the multiplexed signal. It is actually
> performed on the audio components separately, before mixing
> with the stereo subcarrier. Therefore deemphasis needs to be
n4hy wrote:
> The stereo separation is pretty awesome. However on stations that are
> full quieting with monoaural transmissions, the stereo demultiplexer is
> introducing hiss.On really strong stations, it is hard to hear.
> The deemphasis has been removed from the processing chain while I
The stereo separation is pretty awesome. However on stations that are
full quieting with monoaural transmissions, the stereo demultiplexer is
introducing hiss.On really strong stations, it is hard to hear.
The deemphasis has been removed from the processing chain while I try
and figure o
As an interim to "really" solving the problem. I hacked the gains on
the carrier and stereo DSBSC signal.
My favorite test is
usrp_wfm_rcv -f
and then
usrp_wfm_rcv_pll -f
I will never be able to go back as the stereo separation and fidelity
are now much improved.
wfm_rcv_pll.py checked
