[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Discuss-gnuradio] How are parameters of gfsk_demod block assigned?
From: |
Kun Qian |
Subject: |
[Discuss-gnuradio] How are parameters of gfsk_demod block assigned? |
Date: |
Sun, 3 Aug 2014 19:41:12 -0700 (PDT) |
Hi,
I recently triy to receive ibeacon signal whose modulation scheme is GFSK,
so I use the /gfsk_demod/ block in gnuradio and succeed to demodulate
ibeacon signal. Yet I don't understand the meaning of some of its parameters
and why these parameters are assigned to some certain values. For example,
the parameter /gain_mu/ is set to 0.175 as default.
I then read the codes of /gfsk_demod/ and find that there is actually one
step of clock recovery there. Then I read the papers cited by the
documentation of /gfsk_demod/ block and learn the principle of the digital
clock recovery algorithm used in it.
As far as I know, the Mueller and Muller algorithm uses linear combination
of samples to estimate the timing error, which is then used to adjust the
sampling phase. So the parameter /omega/ is the estimate of timing shift
caused by carrier frequency shift, the parameter /mu/ is the estimate of
final timing shift, and /gain_omega/ and /gain_mu/ are weights of estimate
of timing error when adjust respective parameters, is it correct?
Then the last question is how are these parameters assigned? For example,
/gain_mu/ is set to be 0.175 and /gain_omega/ is set to be
0.25*/gain_mu/*/gain_mu/. Are these assignment related to any previous works
or derivatives or some experiments or simulations? Do these values have any
special meaning?
Thanks,
Kun Qian
--
View this message in context:
http://gnuradio.4.n7.nabble.com/How-are-parameters-of-gfsk-demod-block-assigned-tp49734.html
Sent from the GnuRadio mailing list archive at Nabble.com.
[Prev in Thread] |
Current Thread |
[Next in Thread] |
- [Discuss-gnuradio] How are parameters of gfsk_demod block assigned?,
Kun Qian <=