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authorMauro Carvalho Chehab <mchehab@redhat.com>2011-11-11 12:46:23 -0200
committerMauro Carvalho Chehab <mchehab@redhat.com>2011-11-11 12:46:23 -0200
commit39ce61a846c8e1fa00cb57ad5af021542e6e8403 (patch)
treefc2ece73b3c54a805f9ac85d390f2388f741b46c /Documentation/DocBook
parente9eb0dadba932940f721f9d27544a7818b2fa1c5 (diff)
[media] dvb: Allow select between DVB-C Annex A and Annex C
DVB-C, as defined by ITU-T J.83 has 3 annexes. The differences between Annex A and Annex C is that Annex C uses a subset of the modulation types, and uses a different rolloff factor. A different rolloff means that the bandwidth required is slicely different, and may affect the saw filter configuration at the tuners. Also, some demods have different configurations, depending on using Annex A or Annex C. So, allow userspace to specify it, by changing the rolloff factor. Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Diffstat (limited to 'Documentation/DocBook')
-rw-r--r--Documentation/DocBook/media/dvb/dvbproperty.xml4
1 files changed, 4 insertions, 0 deletions
diff --git a/Documentation/DocBook/media/dvb/dvbproperty.xml b/Documentation/DocBook/media/dvb/dvbproperty.xml
index 3bc8a61efe30..6ac803959a47 100644
--- a/Documentation/DocBook/media/dvb/dvbproperty.xml
+++ b/Documentation/DocBook/media/dvb/dvbproperty.xml
@@ -311,6 +311,8 @@ typedef enum fe_rolloff {
ROLLOFF_20,
ROLLOFF_25,
ROLLOFF_AUTO,
+ ROLLOFF_15, /* DVB-C Annex A */
+ ROLLOFF_13, /* DVB-C Annex C */
} fe_rolloff_t;
</programlisting>
</section>
@@ -778,8 +780,10 @@ typedef enum fe_hierarchy {
<listitem><para><link linkend="DTV-MODULATION"><constant>DTV_MODULATION</constant></link></para></listitem>
<listitem><para><link linkend="DTV-INVERSION"><constant>DTV_INVERSION</constant></link></para></listitem>
<listitem><para><link linkend="DTV-SYMBOL-RATE"><constant>DTV_SYMBOL_RATE</constant></link></para></listitem>
+ <listitem><para><link linkend="DTV-ROLLOFF"><constant>DTV_ROLLOFF</constant></link></para></listitem>
<listitem><para><link linkend="DTV-INNER-FEC"><constant>DTV_INNER_FEC</constant></link></para></listitem>
</itemizedlist>
+ <para>The Rolloff of 0.15 (ROLLOFF_15) is assumed, as ITU-T J.83 Annex A is more common. For Annex C, rolloff should be 0.13 (ROLLOFF_13). All other values are invalid.</para>
</section>
<section id="dvbc-annex-b-params">
<title>DVB-C Annex B delivery system</title>