Dvb constellation: Difference between revisions
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(Build DVB constellation in Linux) |
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resulting image will be saved into iq_dvbc_qam256.png. Here is example of images received with [[NetUP_Dual_DVB_T_C_CI_RF|NetUP Dual DVB-T/C-CI RF]] and [[NetUP_Dual_DVB_S2_CI|NetUP Dual DVB S2 CI]] cards. |
resulting image will be saved into iq_dvbc_qam256.png. Here is example of images received with [[NetUP_Dual_DVB_T_C_CI_RF|NetUP Dual DVB-T/C-CI RF]] and [[NetUP_Dual_DVB_S2_CI|NetUP Dual DVB S2 CI]] cards. |
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[[Image:Iq_dvbc_qam16_38db.png|QAM16 constellation on NetUP Dual DVB-T/C-CI card]] |
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[[Image:Iq_dvbc_qam64_38db.png|QAM64 constellation on NetUP Dual DVB-T/C-CI card]] |
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[[Image:Iq_dvbc_qam128_38db.png|QAM128 constellation on NetUP Dual DVB-T/C-CI card]] |
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[[Image:Iq_dvbc_qam256_36db.png|QAM256 constellation on NetUP Dual DVB-T/C-CI card]] |
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Revision as of 17:13, 11 May 2013
Receiving I&Q data from DVB demodulator
dvb_const -f /dev/dvb/adapter0/frontend1 -o iq_dvbc_qam256.txt -p 100000
received data (100000 points) will be saved into iq_dvbc_qam256.txt file. File format is simple text csv. Example of received data:
-175,-45 -46,110 -241,-178 176,11 -50,173 16,44
Values are signed. First I part, second Q part.
Visualization of received data
dvb_const_plot utility build PNG image with constellation:
dvb_const_plot -i iq_dvbc_qam256.txt -o iq_dvbc_qam256.png -c "SNR=38dB QAM256"
resulting image will be saved into iq_dvbc_qam256.png. Here is example of images received with NetUP Dual DVB-T/C-CI RF and NetUP Dual DVB S2 CI cards.
