Dvb constellation: Difference between revisions

Revision as of 17:19, 11 May 2013

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.

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.

@@ Line 29: / Line 29: @@
 <gallery>
-File:Iq_dvbc_qam16_38db.png|QAM16 constellation
+File:Iq_dvbc_qam16_38db.png|QAM16 constellation (DVB-C)
-File:Iq_dvbc_qam64_38db.png|QAM64 constellation
+File:Iq_dvbc_qam64_38db.png|QAM64 constellation (DVB-C)
-File:Iq_dvbc_qam128_38db.png|QAM128 constellation
+File:Iq_dvbc_qam128_38db.png|QAM128 constellation (DVB-C)
-File:Iq_dvbc_qam256_36db.png|QAM256 constellation
+File:Iq_dvbc_qam256_36db.png|QAM256 constellation (DVB-C)
 </gallery>