This, is a squelch, variable changes between 0 and positive gain value. -- public PGP key http://pastebin.com/dqZqgyVE
On Mon, Apr 28, 2014 at 1:24 PM, Activecat <[email protected]> wrote: > When I looked into the attached graphical flowgraph in the first email, > the signal was multiplied by zero (constant multiplier) before feeding into > file sink and audio sink. In this case what you get was probably amplified > noise. > Was it zero or something else? > > > > On Fri, Apr 25, 2014 at 11:54 PM, Marcus Müller <[email protected]>wrote: > >> -----BEGIN PGP SIGNED MESSAGE----- >> Hash: SHA1 >> >> A shoot, I overlooked the 64 decimation rate... Sorry about that. >> >> >> On 25.04.2014 17:36, Anton Komarov wrote: >> > Marcus, w/o AGC audio sometimes is creapy. I have tested AGC2, >> > tried to play with attack and decay, but at last when there is a >> > plane in the vicinity dongle overloads and sound become very loud. >> > Then i tested FAGC and it fits well! 1024M/64 gives 16k and 256 >> > samples equals - 62 ms of signal. Works ok for me. >> > >> > >> > On Fri, Apr 25, 2014 at 7:25 PM, Marcus Müller <[email protected]> >> > wrote: >> > >> > Actually I'm a little confused - Is seeing an AGC in an AM >> > demodulator something you usually do? Especially the feedforward >> > AGC should be rather err jumpy with a scope of but 256 samples, >> > unless I'm missing something; f_sample seems to be 1024ksps, thus >> > 256 samples max search and rescaling should behave very badly if >> > there are baseband signal contents below 4kHz -- and that should be >> > the case for audio, usually? >> > >> > Greetings, Marcus >> > >> > On 25.04.2014 16:03, Marcus Leech wrote: >> >>>> An AM demodulator is a squaring function. It can only >> >>>> *ever* produce positive values. You can remove DC offset by >> >>>> using a high-pass filter after it. on Apr 25, 2014, *Anton >> >>>> Komarov* <[email protected]> wrote: >> >>>> >> >>>> But when we have only positive values that means in fact we >> >>>> have 0.5 DC offset, and that is bad. Moreover i've made test >> >>>> recording with GQRX - waveform is fine! Looking into the >> >>>> code, nothing special, am demod->low-pass->wav-sink. >> >>>> >> >>>> -- public PGP key http://pastebin.com/dqZqgyVE >> >>>> >> >>>> >> >>>> On Fri, Apr 25, 2014 at 5:11 PM, Michael Ossmann >> >>>> <[email protected] <mailto:[email protected]>> wrote: >> >>>> >> >>>> On Fri, Apr 25, 2014 at 04:14:30PM +0400, Anton Komarov >> >>>> wrote: >> >>>>> >> >>>>> Hi, you can find in attach AM demodulator grc file. >> >>>>> Everything is straight forward with demod but audio file >> >>>>> generated looks weird. Only positive values of amplitude. >> >>>> The particular definition of "amplitude" adopted by GNU Radio >> >>>> (and pretty much everyone else in SDR as far as I know) is >> >>>> "absolute value". It is correct for it to always be >> >>>> positive. >> >>>> >> >>>> >> >>>> >> > >> -------------------------------------------------------------------------------- >> >>>> >> >>>> >> > >> _______________________________________________ Discuss-gnuradio >> >>>> mailing list [email protected] >> >>>> <mailto:[email protected]> >> >>>> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >> >>>> >> >>>> >> >>>> >> >>>> _______________________________________________ >> >>>> Discuss-gnuradio mailing list [email protected] >> >>>> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >> >>>> >> >> >> >> _______________________________________________ Discuss-gnuradio >> >> mailing list [email protected] >> >> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >> >> >> > >> -----BEGIN PGP SIGNATURE----- >> Version: GnuPG v1 >> Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ >> >> iQEbBAEBAgAGBQJTWoU1AAoJEBQ6EdjyzlHtQAYH+KNwTI+XPjKFyb+kId+Y9fxv >> uthK+LH7CTAm85j9gb4mIeGe7Wpe2gZZ0sqvDgyXL594urUSvfbmyCy/p0GI7WfC >> evmwyX4HBZIuXBdqIkj0NdhvwpaBHBYUE1R2JfVIK1ZqaApNtGVxoKpOyI38XCg1 >> m68tsU3HASfVQxIWfuJS0mBgwPo8wSCTXLOoUqc1YTVXd+tXNNAVLbFEDUOgVuib >> irkUhUYdNi85SwO3ildun/9xEwXB3g4FeB3Hq66TccE5M7zvZsOBa4oF/uKITRoG >> cvOc/EuBRCG+u1lI2owwQXsUuGWmHhN+xcjtkzn4Qa+2b+zR9bPPGS70ru45vQ== >> =+L1B >> -----END PGP SIGNATURE----- >> >> _______________________________________________ >> Discuss-gnuradio mailing list >> [email protected] >> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >> > > > _______________________________________________ > Discuss-gnuradio mailing list > [email protected] > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > >
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