Thanks for the answers. All sampling rates are in the 1.5-2.5 MHz range,
namely 11025*128=1.4112 MHz when decoding POCSAG, or 48000*32=1.536 MHz when
decoding commercial FM (for these trivial tests). The issue about
synchronization only arises when an audio sink is used: sending the data to
a named pipe or scope sink displays the "PLL not locked" message but the
decoding/display look fine. I should emphasize that
rtl_fm -f 104.4e6 -M wbfm -s 200000 -r 48000 - | aplay -r 48k -f S16_LE
(running a friend's computer) works perfectly well, hence my concern about
gr-osmosdr at opposed to the RTL libs.
JM
It's hardly a trivial report; RTL devices with gr-osmosdr are a very
commonly used platform.
I've seen similar messages from gqrx, but sound quality has not been
impacted. My guess is that this may be related to rapid retuning for
rtl devices, which basically involves not waiting for the PLL to lock.
Does osmosdr-->nullsink display the same message?
What about rtl_sdr ... > /dev null?
Does this only happen at certain sample rates or at any rate? And are
you using a supported sample rate?
https://github.com/csete/gqrx/commit/d805c426f24f987cdb16e37bbab564d30da473c2
On Mon, Jan 11, 2016 at 11:16 AM, jmfriedt
<jean-michel.fri...@femto-st.fr> wrote:
My apologies for such a trivial bug report, but has anyone
experienced issues with gr-osmosdr
"lately" (not sure when the problem started) about "PLL not locked"
and data flow rate mismatch
in gnuradio data flows ?
I have a couple dozen RTL2832U based dongles used for various SDR
activities which have been
working quite flawlessly until this summer at least. Being
currently in the process of preparing
the new teaching semester, I just discovered that *all* dongles
(E4k, R820T or R820T2) experience
the same lack of PLL locking and data flow rate mismatch when
connected to USB ports *on laptops*
(tested on four different laptop models, yet all running Debian/GNU
Linux distributions, testing
and sid releases). The audio output in such a simple decoding
stream as Osmosdr Source - Low pass
filter - WBFM decoder - audio output is not continuous and of very
bad quality. The *same* dongles
connected to desktop setups with the same Debian/GNU Linux
distribution exhibit no issue: stream
rate is consistent and sound quality excellent. Of course searching
on the web for "PLL not locked"
yields a couple of million hits explaining that the tuned frequency
range is not within the
bandwidth of the dongle VCO, which is not the case here.
Has anyone seen reports of this issue before ?
Thanks, JM
--
JM Friedt, FEMTO-ST Time & Frequency/SENSeOR, 26 rue de l'Epitaphe,
25000 Besancon, France
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--
JM Friedt, FEMTO-ST Time & Frequency/SENSeOR, 26 rue de l'Epitaphe,
25000 Besancon, France
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