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Re: [Discuss-gnuradio] Re: Soft-DVB DVB-T transmitter
From: |
rafael2k |
Subject: |
Re: [Discuss-gnuradio] Re: Soft-DVB DVB-T transmitter |
Date: |
Wed, 12 Nov 2008 10:59:17 -0200 |
User-agent: |
KMail/1.9.9 |
Hello people,
I'm following the discussion about the Soft-DVB, and I'm thinking about use of
the WBX0510 daughterboard (50 MHz to 1 GHz) w/ Soft-DVB - Will then be
possible to transmitt in any VHF/UHF channel?
Bye,
Rafael Diniz
Em Tuesday 11 November 2008, Vincenzo Pellegrini escreveu:
> Martin ,
> sorry for the delay. My exams seem to have gone well even if it's not
> official yet. I also had to do a demo for a company I have a temporary
> contract with for developing some gnuradio based gsm-r security
> sentinels. Also the demo was smooth. (i already listed the project on
> the gnuradio wiki)
> so i really hope i'll be able to prepare the 8Mhz stream for you
> within the next 2/3 days. Would this still be useful?
>
> 2008/11/3, Martin DvH <address@hidden>:
> > On Mon, 2008-11-03 at 14:13 +0100, Martin DvH wrote:
> >> ________________________________
> >>
> >> > Van: address@hidden
> >>
> >> [mailto:address@hidden
> >> Namens Vincenzo Pellegrini
> >>
> >> > Verzonden: maandag 3 november 2008 0:16
> >> > Aan: Martin DvH
> >> > CC: discuss-gnuradio
> >> > Onderwerp: [Discuss-gnuradio] Re: Soft-DVB DVB-T transmitter
> >> >
> >> >
> >> > This is Great... :)
> >> >
> >> > Yup, the playback cannot be smooth because of the wrong throughput,
> >>
> >> definitely.
> >>
> >> > Did you use the USRP1 with interpolation factor = 16 ?
> >>
> >> Yes I did.
> >>
> >> > I can prepare a modulated signal with the correct throughput for
> >>
> >> you.. this is not a problem... :)
> >>
> >> Please do, this would be great.
> >>
> >> > what hard disc are you playing your signal back from?
> >>
> >> Internal 2.5" harddisk of my acer 6930 notebook (Aspire 6930G-734G32BN
> >> LX.AVB0X.135)
> >> 2.5" 320GB HDD 5400rpm, SATA
> >
> > I checked now. It is a:
> > Western digital Scorpio 320 GB SATA (WDC WD3200BEVT-22ZCT0)
> > 2.5-inch SATA Hard Drive 320 GB, 3 Gb/s, 8 MB Cache, 5400 RPM
> >
> > Benchmark from tomshardware (h2benchw 3.6):
> > http://www.tomshardware.com/charts/2-5-hard-drive-charts/Minimum-Read-Tra
> >nsfer-Performance,687.html minimum read transfer rate 33.5 MB/sec
> > average read transfer rate 52.2 MB/sec
> > maximum read transfer rate 68.2 MB/sec
> >
> >> I am not at home right now So I can't check the exact brand and model of
> >> the
> >> harddisk.
> >> It can do around 38 MB/sec so this is just enough (required 32 MB/sec)
> >>
> >> I also have 4GB of memory in this notebook, so I think it will buffer
> >> the complete file.
> >>
> >> I had to use my notebook because with my desktop PC (ASrock
> >> 939-DUAL-SATA2)
> >> The USB TX bandwidth is less then 32 MB/sec.
> >> (Which is strange because I CAN receive 32 MB/sec)
> >> I get UuUuUu on this machine when useing interpolation 16, so unusable.
> >>
> >> Regards,
> >> Martin
> >>
> >> > regards
> >> >
> >> > vincenzo
> >> >
> >> >
> >> > 2008/11/3 Martin DvH <address@hidden>
> >>
> >> Hi,
> >>
> >> > > In fact: 8 complex Msps implement a 7 MHz channel while
> >>
> >> 9.142857143
> >>
> >> > > complex Msps implement an 8 MHz channel.
> >> > > Just try to go as close as possible to such sampling
> >>
> >> frequency by
> >>
> >> > > using USRP2 and let me know what happens... it could
> >>
> >> turn out that we
> >>
> >> > > need a resampler block.
> >> >
> >> > So if I use a fractional rate resampler with interpolation
> >>
> >> factor
> >>
> >> > 10/8=1.25 I get a 7 Mhz channel with 10 Msps samplerate.
> >> > If I use a fractional rate resampler with interpolation
> >>
> >> factor
> >>
> >> > 10/9.142857143=1.09375 I get a 8 Mhz channel with 10 Msps
> >>
> >> samplerate
> >>
> >> > If I use a fractional rate resampler with DECIMATION
> >>
> >> factor
> >>
> >> > 9.142857143/8=8/7=1.142857143 I get a 8 Mhz channel with 8
> >>
> >> Msps
> >>
> >> > samplerate with the out-of-band skirts folded back at the
> >>
> >> sides.
> >>
> >> > Would be interesting to see if this last one works with a
> >>
> >> USRP1.
> >>
> >> > I'll let you know how the experiments go.
> >>
> >> I resampled and scaled your ofdm_40.dump file so it now will
> >> use 8 Mhz bandwidth with a 8 Msps samplerate.
> >> The reception never can be perfect this way but it seems
> >> good enough for
> >> tests.
> >>
> >> My USB DVB-T receiver receives the transport stream without
> >> problems.
> >> Mplayer playes the stream without problem for two loops and
> >> then crashes
> >> with a broken frame.
> >> My standalone settopbox DVB-T receiver now also receives the
> >> stream.
> >> (8 MHz channel on UHF)
> >> It has big problems displaying it. Sound is only a chop of
> >> sound now and
> >> then and video stops, then runs for a second, then stops
> >> again.
> >>
> >> I think this is because the timestamps and framerate
> >> (playout speed)
> >> don't match the data throughput of the MPEG stream anymore.
> >> (It is getting the stream too fast)
> >>
> >> I put my resampled RF file at:
> >>
> >> http://www.olifantasia.com/projects/gnuradio/mdvh/OTA/DVB-T/ofdm_40_bw8M
> >>hz_s amplerate_8Msps_cshort.raw
> >>
> >> format is complex signed short integers (I 16 bit, Q 16 bit)
> >> at 8
> >> Msamples/sec.
> >>
> >>
> >> Greetings,
> >> Martin
> >>
> >> > > more details will follow as soon as I find some time...
> >> >
> >> > Thanks and success with your second group of tests.
> >> >
> >> > Martin
> >> >
> >> > > best regards and greetings
> >> > > to all fellow GNURadioers
> >> > >
> >> > > vincenzo
> >> > >
> >> > > PS
> >> > > Rafael, just have a look back a this thread and you'll
> >>
> >> find all the
> >>
> >> > > info you need to do your test broadcast. Thanks for your
> >>
> >> interest
> >>
> >> > > 2008/10/31 Martin Dudok van Heel
> >>
> >> <address@hidden>
> >>
> >> > > Hi Vincenzo.
> >> > > How are things going with your exams.
> >> > >
> >> > > I hope well.
> >> > >
> >> > > Thanks for your help so far.
> >> > >
> >> > > I finally got your DVB-T dump streams working.
> >> > > I first tried using an undersampled basicTX but
> >>
> >> never got it
> >>
> >> > > to work.
> >> > > (use a niquist mirror in the VHF range on
> >>
> >> channel 11 or 12
> >>
> >> > > (219.5 Mhz or 226.5 Mhz))
> >> > >
> >> > > I now use a RFX900 and that works with a
> >>
> >> pinnacle PCTV-Solo
> >>
> >> > > 72e usb DVB-T receiver card plugged into my PC.
> >> > > I use 858.0 Mhz (channel 69)
> >> > > I used a 10 dB attenuator on the antenna output
> >>
> >> to limit
> >>
> >> > > output power.
> >> > > I also modified the RFX900 to enable
> >>
> >> transmitting outside of
> >>
> >> > > the ISM band. (disable saw-filter. add 220 pF
> >>
> >> capacitor)
> >>
> >> > > Apparantly the pinnacle 72e can receive 7 Mhz
> >>
> >> channels on the
> >>
> >> > > UHF channels.
> >> > > My standalone settopbox DVB-T receiver can't
> >>
> >> handle it.
> >>
> >> > > I noticed you don't use the full possible range
> >>
> >> in your 16 bit
> >>
> >> > > streams.
> >> > > (only goes from -80 to +80 while you could use
> >>
> >> -8192 to 8192)
> >>
> >> > > Is this on purpose?
> >> > > I can multiply samples by 64 and get a cleaner
> >>
> >> signal. (But
> >>
> >> > > also more output power)
> >> > >
> >> > >
> >> > > I do have a request, I hope it is not too much
> >>
> >> work.
> >>
> >> > > Could you make a stream with 10 Msamples/sec
> >>
> >> samplerate and 8
> >>
> >> > > Mhz wide channel.
> >> > > This way I can use standard standalone DVB-T
> >>
> >> receivers and
> >>
> >> > > don't have the 7Mhz bandwith on UHF problem.
> >> > >
> >> > > For the 10 Msps stream I would have to use my
> >>
> >> USRP2 to output
> >>
> >> > > it.
> >> > > It has a 100 Mhz DAC (in stead of 64 Msps in the
> >>
> >> USRP1)
> >>
> >> > > It has a gbit ethernet connection for the
> >>
> >> samples, so I can go
> >>
> >> > > up to 25 Msps.
> >> > > It can only do fixed interpolation rates so I
> >>
> >> have to choose
> >>
> >> > > from the table below.
> >> > > (8 Msamples/sec is not supported on the USRP2)
> >> > >
> >> > >
> >> > > USRP2
> >> > > dac_rate interp ethernet_sample_rate
> >> > > 100 4 25
> >> > > 100 5 20
> >> > > 100 6 16.67
> >> > > 100 7 14.29
> >> > > 100 8 12.5
> >> > > 100 9 11.11
> >> > > 100 10 10 <----I think 10
> >>
> >> Msamples/sec
> >>
> >> > > should be optimal
> >> > > 100 11 9.09
> >> > > 100 12 8.33
> >> > > 100 13 7.69
> >> > > 100 14 7.14
> >> > >
> >> > >
> >> > > I think 10 Msamples/sec would be a good
> >>
> >> candidate.
> >>
> >> > > Have you also tried using 8 Msamples/sec on the
> >>
> >> USRP1?
> >>
> >> > > I know there would be no room left for IF
> >>
> >> channel filtering,
> >>
> >> > > but it could in theory still work.
> >> > > If this works I would also very much appreciate
> >>
> >> a 8Mhz
> >>
> >> > > bandwidth stream with 8 MSPS samplerate so I can
> >>
> >> demonstrate
> >>
> >> > > with a standard USRP1.
> >> > >
> >> > > Thanks for your help so far.
> >> > > I appreciate it very much.
> >> > >
> >> > > And good luck with your exams.
> >> > >
> >> > > Have a nice weekend.
> >> > >
> >> > > Greetings,
> >> > > Martin
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- [Discuss-gnuradio] Re: Soft-DVB DVB-T transmitter, Vincenzo Pellegrini, 2008/11/01
- [Discuss-gnuradio] Re: Soft-DVB DVB-T transmitter, Martin DvH, 2008/11/02
- [Discuss-gnuradio] Re: Soft-DVB DVB-T transmitter, Martin DvH, 2008/11/02
- [Discuss-gnuradio] Re: Soft-DVB DVB-T transmitter, Vincenzo Pellegrini, 2008/11/02
- RE: [Discuss-gnuradio] Re: Soft-DVB DVB-T transmitter, Martin DvH, 2008/11/03
- RE: [Discuss-gnuradio] Re: Soft-DVB DVB-T transmitter, Martin DvH, 2008/11/03
- [Discuss-gnuradio] Re: Soft-DVB DVB-T transmitter, Vincenzo Pellegrini, 2008/11/11
- Re: [Discuss-gnuradio] Re: Soft-DVB DVB-T transmitter,
rafael2k <=
- [Discuss-gnuradio] Re: Soft-DVB DVB-T transmitter, Vincenzo Pellegrini, 2008/11/11
- Re: [Discuss-gnuradio] Re: Soft-DVB DVB-T transmitter, Martin DvH, 2008/11/14