Hi Alex,
You might be interested in:
https://wiki.gnuradio.org/index.php/Sample_Rate_Tutorial#Source_hardware_example
It's a little different approach, but works very well. Contact me if you
have any questions.
Happy New Year to you too.
--
Barry Duggan KV4FV
On Wed, 8 Jan 2020 13:57:09 -0600, Alex Roberts wrote:
Hello Mailing List,
Happy New Year!
I've been playing around with this (
http://aaronscher.com/GNU_Radio_Companion_Collection/Audio_Modem_loop_back_test_FSK.html)
FSK audio modem and have a few issues/questions.
1) Is the PFB block the way to go for FSK timing recovery? I have issues
where if I start the receiver before the transmitter, the system doesn't
work. And if I start the transmitter before the receiver, it will
eventually lose sync and never recover. I added a message strobe to send
dummy data once a second (like a keep alive/heartbeat) and this helps it
from losing sync in between time of when I send meaningful data.
1a) Reading docs on both PFB and M&M blocks, do I need a moving avg.
filter
after quad demod to round out the square pulses to allow PFB and M&M to
better find peaks or is the moving avg filter implemented within the
block?
2) Is the pre-amble being muxed doing anything more than just padding my
data to help the PFB lock in before actual data arrives?
3) Would the Correlation Estimator help since it can send "time_est"
tags
downstream to the PFB and if so, where would be the ideal place to put
it?
Cheers,
Alex
