Documentation/DocBook/dvb/dvbproperty.xml

   1 <section id="FE_GET_PROPERTY">
   2 <title>FE_GET_PROPERTY/FE_SET_PROPERTY</title>
   3
   4 <section id="isdbt">
   5         <title>ISDB-T frontend</title>
   6         <para>This section describes shortly what are the possible parameters in the Linux
   7                 DVB-API called "S2API" and now DVB API 5 in order to tune an ISDB-T/ISDB-Tsb
   8                 demodulator:</para>
   9
  10         <para>This ISDB-T/ISDB-Tsb API extension should reflect all information
  11                 needed to tune any ISDB-T/ISDB-Tsb hardware. Of course it is possible
  12                 that some very sophisticated devices won't need certain parameters to
  13                 tune.</para>
  14
  15         <para>The information given here should help application writers to know how
  16                 to handle ISDB-T and ISDB-Tsb hardware using the Linux DVB-API.</para>
  17
  18         <para>The details given here about ISDB-T and ISDB-Tsb are just enough to
  19                 basically show the dependencies between the needed parameter values,
  20                 but surely some information is left out. For more detailed information
  21                 see the following documents:</para>
  22
  23         <para>ARIB STD-B31 - "Transmission System for Digital Terrestrial
  24                 Television Broadcasting" and</para>
  25         <para>ARIB TR-B14 - "Operational Guidelines for Digital Terrestrial
  26                 Television Broadcasting".</para>
  27
  28         <para>In order to read this document one has to have some knowledge the
  29                 channel structure in ISDB-T and ISDB-Tsb. I.e. it has to be known to
  30                 the reader that an ISDB-T channel consists of 13 segments, that it can
  31                 have up to 3 layer sharing those segments, and things like that.</para>
  32
  33         <para>Parameters used by ISDB-T and ISDB-Tsb.</para>
  34
  35         <section id="isdbt-parms">
  36                 <title>Parameters that are common with DVB-T and ATSC</title>
  37
  38                 <section id="isdbt-freq">
  39                         <title><constant>DTV_FREQUENCY</constant></title>
  40
  41                         <para>Central frequency of the channel.</para>
  42
  43                         <para>For ISDB-T the channels are usually transmitted with an offset of 143kHz. E.g. a
  44                                 valid frequncy could be 474143 kHz. The stepping is bound to the bandwidth of
  45                                 the channel which is 6MHz.</para>
  46
  47                         <para>As in ISDB-Tsb the channel consists of only one or three segments the
  48                                 frequency step is 429kHz, 3*429 respectively. As for ISDB-T the
  49                                 central frequency of the channel is expected.</para>
  50                 </section>
  51
  52                 <section id="isdbt-bw">
  53                         <title><constant>DTV_BANDWIDTH_HZ</constant> (optional)</title>
  54
  55                         <para>Possible values:</para>
  56
  57                         <para>For ISDB-T it should be always 6000000Hz (6MHz)</para>
  58                         <para>For ISDB-Tsb it can vary depending on the number of connected segments</para>
  59
  60                         <para>Note: Hardware specific values might be given here, but standard
  61                                 applications should not bother to set a value to this field as
  62                                 standard demods are ignoring it anyway.</para>
  63
  64                         <para>Bandwidth in ISDB-T is fixed (6MHz) or can be easily derived from
  65                                 other parameters (DTV_ISDBT_SB_SEGMENT_IDX,
  66                                 DTV_ISDBT_SB_SEGMENT_COUNT).</para>
  67                 </section>
  68
  69                 <section id="isdbt-delivery-sys">
  70                         <title><constant>DTV_DELIVERY_SYSTEM</constant></title>
  71
  72                         <para>Possible values: <constant>SYS_ISDBT</constant></para>
  73                 </section>
  74
  75                 <section id="isdbt-tx-mode">
  76                         <title><constant>DTV_TRANSMISSION_MODE</constant></title>
  77
  78                         <para>ISDB-T supports three carrier/symbol-size: 8K, 4K, 2K. It is called
  79                                 'mode' in the standard: Mode 1 is 2K, mode 2 is 4K, mode 3 is 8K</para>
  80
  81                         <para>Possible values: <constant>TRANSMISSION_MODE_2K</constant>, <constant>TRANSMISSION_MODE_8K</constant>,
  82                                 <constant>TRANSMISSION_MODE_AUTO</constant>, <constant>TRANSMISSION_MODE_4K</constant></para>
  83
  84                         <para>If <constant>DTV_TRANSMISSION_MODE</constant> is set the <constant>TRANSMISSION_MODE_AUTO</constant> the
  85                                 hardware will try to find the correct FFT-size (if capable) and will
  86                                 use TMCC to fill in the missing parameters.</para>
  87
  88                         <para><constant>TRANSMISSION_MODE_4K</constant> is added at the same time as the other new parameters.</para>
  89                 </section>
  90
  91                 <section id="isdbt-guard-interval">
  92                         <title><constant>DTV_GUARD_INTERVAL</constant></title>
  93
  94                         <para>Possible values: <constant>GUARD_INTERVAL_1_32</constant>, <constant>GUARD_INTERVAL_1_16</constant>, <constant>GUARD_INTERVAL_1_8</constant>,
  95                                 <constant>GUARD_INTERVAL_1_4</constant>, <constant>GUARD_INTERVAL_AUTO</constant></para>
  96
  97                         <para>If <constant>DTV_GUARD_INTERVAL</constant> is set the <constant>GUARD_INTERVAL_AUTO</constant> the hardware will
  98                                 try to find the correct guard interval (if capable) and will use TMCC to fill
  99                                 in the missing parameters.</para>
 100                 </section>
 101         </section>
 102         <section id="isdbt-new-parms">
 103                 <title>ISDB-T only parameters</title>
 104
 105                 <section id="isdbt-part-rec">
 106                         <title><constant>DTV_ISDBT_PARTIAL_RECEPTION</constant></title>
 107
 108                         <para><constant>If DTV_ISDBT_SOUND_BROADCASTING</constant> is '0' this bit-field represents whether
 109                                 the channel is in partial reception mode or not.</para>
 110
 111                         <para>If '1' <constant>DTV_ISDBT_LAYERA_*</constant> values are assigned to the center segment and
 112                                 <constant>DTV_ISDBT_LAYERA_SEGMENT_COUNT</constant> has to be '1'.</para>
 113
 114                         <para>If in addition <constant>DTV_ISDBT_SOUND_BROADCASTING</constant> is '1'
 115                                 <constant>DTV_ISDBT_PARTIAL_RECEPTION</constant> represents whether this ISDB-Tsb channel
 116                                 is consisting of one segment and layer or three segments and two layers.</para>
 117
 118                         <para>Possible values: 0, 1, -1 (AUTO)</para>
 119                 </section>
 120
 121                 <section id="isdbt-sound-bcast">
 122                         <title><constant>DTV_ISDBT_SOUND_BROADCASTING</constant></title>
 123
 124                         <para>This field represents whether the other DTV_ISDBT_*-parameters are
 125                                 referring to an ISDB-T and an ISDB-Tsb channel. (See also
 126                                 <constant>DTV_ISDBT_PARTIAL_RECEPTION</constant>).</para>
 127
 128                         <para>Possible values: 0, 1, -1 (AUTO)</para>
 129                 </section>
 130
 131                 <section id="isdbt-sb-ch-id">
 132                         <title><constant>DTV_ISDBT_SB_SUBCHANNEL_ID</constant></title>
 133
 134                         <para>This field only applies if <constant>DTV_ISDBT_SOUND_BROADCASTING</constant> is '1'.</para>
 135
 136                         <para>(Note of the author: This might not be the correct description of the
 137                                 <constant>SUBCHANNEL-ID</constant> in all details, but it is my understanding of the technical
 138                                 background needed to program a device)</para>
 139
 140                         <para>An ISDB-Tsb channel (1 or 3 segments) can be broadcasted alone or in a
 141                                 set of connected ISDB-Tsb channels. In this set of channels every
 142                                 channel can be received independently. The number of connected
 143                                 ISDB-Tsb segment can vary, e.g. depending on the frequency spectrum
 144                                 bandwidth available.</para>
 145
 146                         <para>Example: Assume 8 ISDB-Tsb connected segments are broadcasted. The
 147                                 broadcaster has several possibilities to put those channels in the
 148                                 air: Assuming a normal 13-segment ISDB-T spectrum he can align the 8
 149                                 segments from position 1-8 to 5-13 or anything in between.</para>
 150
 151                         <para>The underlying layer of segments are subchannels: each segment is
 152                                 consisting of several subchannels with a predefined IDs. A sub-channel
 153                                 is used to help the demodulator to synchronize on the channel.</para>
 154
 155                         <para>An ISDB-T channel is always centered over all sub-channels. As for
 156                                 the example above, in ISDB-Tsb it is no longer as simple as that.</para>
 157
 158                         <para><constant>The DTV_ISDBT_SB_SUBCHANNEL_ID</constant> parameter is used to give the
 159                                 sub-channel ID of the segment to be demodulated.</para>
 160
 161                         <para>Possible values: 0 .. 41, -1 (AUTO)</para>
 162                 </section>
 163
 164                 <section id="isdbt-sb-seg-idx">
 165
 166                         <title><constant>DTV_ISDBT_SB_SEGMENT_IDX</constant></title>
 167
 168                         <para>This field only applies if <constant>DTV_ISDBT_SOUND_BROADCASTING</constant> is '1'.</para>
 169
 170                         <para><constant>DTV_ISDBT_SB_SEGMENT_IDX</constant> gives the index of the segment to be
 171                                 demodulated for an ISDB-Tsb channel where several of them are
 172                                 transmitted in the connected manner.</para>
 173
 174                         <para>Possible values: 0 .. <constant>DTV_ISDBT_SB_SEGMENT_COUNT</constant> - 1</para>
 175
 176                         <para>Note: This value cannot be determined by an automatic channel search.</para>
 177                 </section>
 178
 179                 <section id="isdbt-sb-seg-cnt">
 180                         <title><constant>DTV_ISDBT_SB_SEGMENT_COUNT</constant></title>
 181
 182                         <para>This field only applies if <constant>DTV_ISDBT_SOUND_BROADCASTING</constant> is '1'.</para>
 183
 184                         <para><constant>DTV_ISDBT_SB_SEGMENT_COUNT</constant> gives the total count of connected ISDB-Tsb
 185                                 channels.</para>
 186
 187                         <para>Possible values: 1 .. 13</para>
 188
 189                         <para>Note: This value cannot be determined by an automatic channel search.</para>
 190                 </section>
 191
 192                 <section id="isdb-hierq-layers">
 193                         <title>Hierarchical layers</title>
 194
 195                         <para>ISDB-T channels can be coded hierarchically. As opposed to DVB-T in
 196                                 ISDB-T hierarchical layers can be decoded simultaneously. For that
 197                                 reason a ISDB-T demodulator has 3 viterbi and 3 reed-solomon-decoders.</para>
 198
 199                         <para>ISDB-T has 3 hierarchical layers which each can use a part of the
 200                                 available segments. The total number of segments over all layers has
 201                                 to 13 in ISDB-T.</para>
 202
 203                         <section id="isdbt-layer-ena">
 204                                 <title><constant>DTV_ISDBT_LAYER_ENABLED</constant></title>
 205
 206                                 <para>Hierarchical reception in ISDB-T is achieved by enabling or disabling
 207                                         layers in the decoding process. Setting all bits of
 208                                         <constant>DTV_ISDBT_LAYER_ENABLED</constant> to '1' forces all layers (if applicable) to be
 209                                         demodulated. This is the default.</para>
 210
 211                                 <para>If the channel is in the partial reception mode
 212                                         (<constant>DTV_ISDBT_PARTIAL_RECEPTION</constant> = 1) the central segment can be decoded
 213                                         independently of the other 12 segments. In that mode layer A has to
 214                                         have a <constant>SEGMENT_COUNT</constant> of 1.</para>
 215
 216                                 <para>In ISDB-Tsb only layer A is used, it can be 1 or 3 in ISDB-Tsb
 217                                         according to <constant>DTV_ISDBT_PARTIAL_RECEPTION</constant>. <constant>SEGMENT_COUNT</constant> must be filled
 218                                         accordingly.</para>
 219
 220                                 <para>Possible values: 0x1, 0x2, 0x4 (|-able)</para>
 221
 222                                 <para><constant>DTV_ISDBT_LAYER_ENABLED[0:0]</constant> - layer A</para>
 223                                 <para><constant>DTV_ISDBT_LAYER_ENABLED[1:1]</constant> - layer B</para>
 224                                 <para><constant>DTV_ISDBT_LAYER_ENABLED[2:2]</constant> - layer C</para>
 225                                 <para><constant>DTV_ISDBT_LAYER_ENABLED[31:3]</constant> unused</para>
 226                         </section>
 227
 228                         <section id="isdbt-layer-fec">
 229                                 <title><constant>DTV_ISDBT_LAYER*_FEC</constant></title>
 230
 231                                 <para>Possible values: <constant>FEC_AUTO</constant>, <constant>FEC_1_2</constant>, <constant>FEC_2_3</constant>, <constant>FEC_3_4</constant>, <constant>FEC_5_6</constant>, <constant>FEC_7_8</constant></para>
 232                         </section>
 233
 234                         <section id="isdbt-layer-mod">
 235                                 <title><constant>DTV_ISDBT_LAYER*_MODULATION</constant></title>
 236
 237                                 <para>Possible values: <constant>QAM_AUTO</constant>, QP<constant>SK, QAM_16</constant>, <constant>QAM_64</constant>, <constant>DQPSK</constant></para>
 238
 239                                 <para>Note: If layer C is <constant>DQPSK</constant> layer B has to be <constant>DQPSK</constant>. If layer B is <constant>DQPSK</constant>
 240                                         and <constant>DTV_ISDBT_PARTIAL_RECEPTION</constant>=0 layer has to be <constant>DQPSK</constant>.</para>
 241                         </section>
 242
 243                         <section id="isdbt-layer-seg-cnt">
 244                                 <title><constant>DTV_ISDBT_LAYER*_SEGMENT_COUNT</constant></title>
 245
 246                                 <para>Possible values: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, -1 (AUTO)</para>
 247
 248                                 <para>Note: Truth table for <constant>DTV_ISDBT_SOUND_BROADCASTING</constant> and
 249                                         <constant>DTV_ISDBT_PARTIAL_RECEPTION</constant> and <constant>LAYER</constant>*_SEGMENT_COUNT</para>
 250
 251                                 <informaltable id="isdbt-layer_seg-cnt-table">
 252                                         <tgroup cols="6">
 253
 254                                                 <tbody>
 255                                                         <row>
 256                                                                 <entry>PR</entry>
 257                                                                 <entry>SB</entry>
 258                                                                 <entry>Layer A width</entry>
 259                                                                 <entry>Layer B width</entry>
 260                                                                 <entry>Layer C width</entry>
 261                                                                 <entry>total width</entry>
 262                                                         </row>
 263
 264                                                         <row>
 265                                                                 <entry>0</entry>
 266                                                                 <entry>0</entry>
 267                                                                 <entry>1 .. 13</entry>
 268                                                                 <entry>1 .. 13</entry>
 269                                                                 <entry>1 .. 13</entry>
 270                                                                 <entry>13</entry>
 271                                                         </row>
 272
 273                                                         <row>
 274                                                                 <entry>1</entry>
 275                                                                 <entry>0</entry>
 276                                                                 <entry>1</entry>
 277                                                                 <entry>1 .. 13</entry>
 278                                                                 <entry>1 .. 13</entry>
 279                                                                 <entry>13</entry>
 280                                                         </row>
 281
 282                                                         <row>
 283                                                                 <entry>0</entry>
 284                                                                 <entry>1</entry>
 285                                                                 <entry>1</entry>
 286                                                                 <entry>0</entry>
 287                                                                 <entry>0</entry>
 288                                                                 <entry>1</entry>
 289                                                         </row>
 290
 291                                                         <row>
 292                                                                 <entry>1</entry>
 293                                                                 <entry>1</entry>
 294                                                                 <entry>1</entry>
 295                                                                 <entry>2</entry>
 296                                                                 <entry>0</entry>
 297                                                                 <entry>13</entry>
 298                                                         </row>
 299                                                 </tbody>
 300
 301                                         </tgroup>
 302                                 </informaltable>
 303
 304                         </section>
 305
 306                         <section id="isdbt_layer_t_interl">
 307                                 <title><constant>DTV_ISDBT_LAYER*_TIME_INTERLEAVING</constant></title>
 308
 309                                 <para>Possible values: 0, 1, 2, 3, -1 (AUTO)</para>
 310
 311                                 <para>Note: The real inter-leaver depth-names depend on the mode (fft-size); the values
 312                                         here are referring to what can be found in the TMCC-structure -
 313                                         independent of the mode.</para>
 314                         </section>
 315                 </section>
 316         </section>
 317 </section>
 318 </section>