Re: 1) Well, if this doesn't work on a stream with sps>1, it's no use trying it over the air. You just get additional problems! Also, I kind of doubt you should use the term FSK for something that is only one sample long – a single sample doesn't have a frequency, right?
Re: 3) wait! You have a bit rate of 1.041667 Mb/s. You've got a modulation that carries 1 bit per symbol (1b/sym), if I understand correctly (do I?). That means that you will need 1.041667 Msym/s, right? This means you have to use the channel 1.051677 million times per second. This can, physically, not happen with a bandwidth below 1.041677 MHz. So your system is impossible, unless I'm missing something here. Best regards, Marcus On 09.06.2016 17:59, Olivier Goyette wrote: > Sorry for the inconvenience, > 1 - Yes I tried, BUT ! the only way I manage to make this works is by > plugging the following blocks : File source -> RS encoder -> packed to > unpacked -> CPFSK -> Quad demod -> binary slicer -> unpacked to packed > -> RS Decoder -> File sink . All of this work only if I set > Samples/symbols to 1 in the CPFSK block. I've been told before that it > cannot work like this on a real transmission because with > Samples/symbols set to 1, you can't do any pulse shaping. > > 2- look at the pic joined in this e-mail. I don't understand why > there's only one spike in the spectrum??? > > 3 - I need +/-312.5 kHz of deviation with a modulation index of 0,6. I > need a bit rate of 1041667 Mbps. I set a sampling rate of 6.25 M only > because it's 6 times the bit rate so, samples/symbols in CPFSK block > will be set to 6. > > All this is due to the spec sheets of the UAT I'm trying to develop. > This is the aviation industry's standards and I need to respect them > to be approved. If someone would like to see the specs, I have a PDF > that explains it all and I would be glad to share it with you ! > > Thank you > > Olivier > > > > 2016-06-09 11:37 GMT-04:00 Marcus Müller <marcus.muel...@ettus.com > <mailto:marcus.muel...@ettus.com>>: > > Hi Olivier, > > trying to catch up with you here. I've got a few questions! Please > excuse if they've been answered by you before; it's not really > easy to navigate your emails – hint: it gets easier for us to help > you if you use the "reply" button in your email client, so that > things get clearly sorted into some kind of discussion thread. > Also, less emails with condensed questions might be easier to get > answers to. You see, I think very few of us currently get the "big > picture". > > * Have you verified this works in a simulation-only environment, > ie. when you replace the USRP sink/source with a direct GNU > Radio stream? > * Can you post a comparison of Spectrum after the CPFSK > modulator (before the RRC) and after the RRC? Just to verify > the low-pass characteristics of that pulse shaper don't "eat" > the FSK. > * Could you enlighten us a bit about your design goals, i.e. > what's the frequency deviation you want to achieve with the CPFSK? > > Best regards, > Marcus > > > On 09.06.2016 16:50, Olivier Goyette wrote: >> There's something wrong at Tx again. Look at the waterfall I >> joined, we only see one stripe at -312.5 kHz and the signal seems >> to be going like on/off. Don't know what's going on ?? >> >> >> _______________________________________________ >> Discuss-gnuradio mailing list >> Discuss-gnuradio@gnu.org <mailto:Discuss-gnuradio@gnu.org> >> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org <mailto:Discuss-gnuradio@gnu.org> > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > > > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
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