Re: AM demodulation

[Markus Heller]

Dear OMs,

I guess this carrier tracking block would be useful to handle frequency
drift of cheap (unstabilized) devices, when working QO-100 satellite
connections. This block could be used to find the band end beacons and
derive the frequency shift and correct it accordingly. Right?

vy73
markus
dl8rds

Am Montag, den 28.10.2019, 09:44 -0500 schrieb Bill Dailey:
> Can you give a little primer on using that PLL tracking?    I would
> love to use that to just track carriers random frequencies.  For
> instance 10mhz.  Ultimately I want to track and periodically log and
> offset from true predicted frequency. Like every 10 seconds.
> 
> Bill Dailey
> 
> Negativity always wins the short game. But positivity wins the long
> game. - Gary Vaynerchuk
> 
> Don’t be easy to understand, 
> Be impossible to misunderstand 
> - Steve Sims
> 
> > On Oct 28, 2019, at 9:27 AM, Barry Duggan <address@hidden>
> > wrote:
> > 
> > Hi Albin and Volker,
> > 
> > I added a PLL Carrier Tracking block to take care of the tuning
> > problem. See the revised 
> > https://wiki.gnuradio.org/index.php/File:FunCube_AM.png
> > 
> > Albin, that 'spike' is the carrier! This is AM ;)
> > 
> > Thank you both for your suggestions.
> > ---
> > Barry Duggan KV4FV
> > 
> > 
> > On 2019-10-27 07:13, Albin Stigö wrote:
> > > Hi Barry,
> > > Some thoughts:
> > > You have a large DC spike at the center, try using the frequency
> > > xlating
> > > fir filter to tune an offset frequency.
> > > Why don't you decimate at the channel filter?
> > > Try observing the signal at various points using the frequency
> > > sink.
> > > Good luck,
> > > Albin SM6WJM
> > > On Sat, Oct 26, 2019, 21:02 Barry Duggan <address@hidden>
> > > wrote:
> > > > Hi,
> > > > I've been working on a gnuradio AM broadcast receiver, and have
> > > > found
> > > > that the tuning is very critical to obtaining clear audio. My
> > > > flowgraph
> > > > can be seen at 
> > > > https://wiki.gnuradio.org/index.php/File:FunCube_AM.png.
> > > > Are there any alternate demodulation methods which are not so
> > > > sensitive
> > > > to exact tuning?
> > > > Thanks,
> > > > --
> > > > Barry Duggan KV4FV