1 .. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later 2 3 .. _frontend-stat-properties: 4 5 ****************************** 6 Frontend statistics indicators 7 ****************************** 8 9 The values are returned via ``dtv_property.stat``. If the property is 10 supported, ``dtv_property.stat.len`` is bigger than zero. 11 12 For most delivery systems, ``dtv_property.stat.len`` will be 1 if the 13 stats is supported, and the properties will return a single value for 14 each parameter. 15 16 It should be noted, however, that new OFDM delivery systems like ISDB 17 can use different modulation types for each group of carriers. On such 18 standards, up to 3 groups of statistics can be provided, and 19 ``dtv_property.stat.len`` is updated to reflect the "global" metrics, 20 plus one metric per each carrier group (called "layer" on ISDB). 21 22 So, in order to be consistent with other delivery systems, the first 23 value at :c:type:`dtv_property.stat.dtv_stats <dtv_stats>` array refers 24 to the global metric. The other elements of the array represent each 25 layer, starting from layer A(index 1), layer B (index 2) and so on. 26 27 The number of filled elements are stored at ``dtv_property.stat.len``. 28 29 Each element of the ``dtv_property.stat.dtv_stats`` array consists on 30 two elements: 31 32 - ``svalue`` or ``uvalue``, where ``svalue`` is for signed values of 33 the measure (dB measures) and ``uvalue`` is for unsigned values 34 (counters, relative scale) 35 36 - ``scale`` - Scale for the value. It can be: 37 38 - ``FE_SCALE_NOT_AVAILABLE`` - The parameter is supported by the 39 frontend, but it was not possible to collect it (could be a 40 transitory or permanent condition) 41 42 - ``FE_SCALE_DECIBEL`` - parameter is a signed value, measured in 43 1/1000 dB 44 45 - ``FE_SCALE_RELATIVE`` - parameter is a unsigned value, where 0 46 means 0% and 65535 means 100%. 47 48 - ``FE_SCALE_COUNTER`` - parameter is a unsigned value that counts 49 the occurrence of an event, like bit error, block error, or lapsed 50 time. 51 52 53 .. _DTV-STAT-SIGNAL-STRENGTH: 54 55 DTV_STAT_SIGNAL_STRENGTH 56 ======================== 57 58 Indicates the signal strength level at the analog part of the tuner or 59 of the demod. 60 61 Possible scales for this metric are: 62 63 - ``FE_SCALE_NOT_AVAILABLE`` - it failed to measure it, or the 64 measurement was not complete yet. 65 66 - ``FE_SCALE_DECIBEL`` - signal strength is in 0.001 dBm units, power 67 measured in miliwatts. This value is generally negative. 68 69 - ``FE_SCALE_RELATIVE`` - The frontend provides a 0% to 100% 70 measurement for power (actually, 0 to 65535). 71 72 73 .. _DTV-STAT-CNR: 74 75 DTV_STAT_CNR 76 ============ 77 78 Indicates the Signal to Noise ratio for the main carrier. 79 80 Possible scales for this metric are: 81 82 - ``FE_SCALE_NOT_AVAILABLE`` - it failed to measure it, or the 83 measurement was not complete yet. 84 85 - ``FE_SCALE_DECIBEL`` - Signal/Noise ratio is in 0.001 dB units. 86 87 - ``FE_SCALE_RELATIVE`` - The frontend provides a 0% to 100% 88 measurement for Signal/Noise (actually, 0 to 65535). 89 90 91 .. _DTV-STAT-PRE-ERROR-BIT-COUNT: 92 93 DTV_STAT_PRE_ERROR_BIT_COUNT 94 ============================ 95 96 Measures the number of bit errors before the forward error correction 97 (FEC) on the inner coding block (before Viterbi, LDPC or other inner 98 code). 99 100 This measure is taken during the same interval as 101 ``DTV_STAT_PRE_TOTAL_BIT_COUNT``. 102 103 In order to get the BER (Bit Error Rate) measurement, it should be 104 divided by 105 :ref:`DTV_STAT_PRE_TOTAL_BIT_COUNT <DTV-STAT-PRE-TOTAL-BIT-COUNT>`. 106 107 This measurement is monotonically increased, as the frontend gets more 108 bit count measurements. The frontend may reset it when a 109 channel/transponder is tuned. 110 111 Possible scales for this metric are: 112 113 - ``FE_SCALE_NOT_AVAILABLE`` - it failed to measure it, or the 114 measurement was not complete yet. 115 116 - ``FE_SCALE_COUNTER`` - Number of error bits counted before the inner 117 coding. 118 119 120 .. _DTV-STAT-PRE-TOTAL-BIT-COUNT: 121 122 DTV_STAT_PRE_TOTAL_BIT_COUNT 123 ============================ 124 125 Measures the amount of bits received before the inner code block, during 126 the same period as 127 :ref:`DTV_STAT_PRE_ERROR_BIT_COUNT <DTV-STAT-PRE-ERROR-BIT-COUNT>` 128 measurement was taken. 129 130 It should be noted that this measurement can be smaller than the total 131 amount of bits on the transport stream, as the frontend may need to 132 manually restart the measurement, losing some data between each 133 measurement interval. 134 135 This measurement is monotonically increased, as the frontend gets more 136 bit count measurements. The frontend may reset it when a 137 channel/transponder is tuned. 138 139 Possible scales for this metric are: 140 141 - ``FE_SCALE_NOT_AVAILABLE`` - it failed to measure it, or the 142 measurement was not complete yet. 143 144 - ``FE_SCALE_COUNTER`` - Number of bits counted while measuring 145 :ref:`DTV_STAT_PRE_ERROR_BIT_COUNT <DTV-STAT-PRE-ERROR-BIT-COUNT>`. 146 147 148 .. _DTV-STAT-POST-ERROR-BIT-COUNT: 149 150 DTV_STAT_POST_ERROR_BIT_COUNT 151 ============================= 152 153 Measures the number of bit errors after the forward error correction 154 (FEC) done by inner code block (after Viterbi, LDPC or other inner 155 code). 156 157 This measure is taken during the same interval as 158 ``DTV_STAT_POST_TOTAL_BIT_COUNT``. 159 160 In order to get the BER (Bit Error Rate) measurement, it should be 161 divided by 162 :ref:`DTV_STAT_POST_TOTAL_BIT_COUNT <DTV-STAT-POST-TOTAL-BIT-COUNT>`. 163 164 This measurement is monotonically increased, as the frontend gets more 165 bit count measurements. The frontend may reset it when a 166 channel/transponder is tuned. 167 168 Possible scales for this metric are: 169 170 - ``FE_SCALE_NOT_AVAILABLE`` - it failed to measure it, or the 171 measurement was not complete yet. 172 173 - ``FE_SCALE_COUNTER`` - Number of error bits counted after the inner 174 coding. 175 176 177 .. _DTV-STAT-POST-TOTAL-BIT-COUNT: 178 179 DTV_STAT_POST_TOTAL_BIT_COUNT 180 ============================= 181 182 Measures the amount of bits received after the inner coding, during the 183 same period as 184 :ref:`DTV_STAT_POST_ERROR_BIT_COUNT <DTV-STAT-POST-ERROR-BIT-COUNT>` 185 measurement was taken. 186 187 It should be noted that this measurement can be smaller than the total 188 amount of bits on the transport stream, as the frontend may need to 189 manually restart the measurement, losing some data between each 190 measurement interval. 191 192 This measurement is monotonically increased, as the frontend gets more 193 bit count measurements. The frontend may reset it when a 194 channel/transponder is tuned. 195 196 Possible scales for this metric are: 197 198 - ``FE_SCALE_NOT_AVAILABLE`` - it failed to measure it, or the 199 measurement was not complete yet. 200 201 - ``FE_SCALE_COUNTER`` - Number of bits counted while measuring 202 :ref:`DTV_STAT_POST_ERROR_BIT_COUNT <DTV-STAT-POST-ERROR-BIT-COUNT>`. 203 204 205 .. _DTV-STAT-ERROR-BLOCK-COUNT: 206 207 DTV_STAT_ERROR_BLOCK_COUNT 208 ========================== 209 210 Measures the number of block errors after the outer forward error 211 correction coding (after Reed-Solomon or other outer code). 212 213 This measurement is monotonically increased, as the frontend gets more 214 bit count measurements. The frontend may reset it when a 215 channel/transponder is tuned. 216 217 Possible scales for this metric are: 218 219 - ``FE_SCALE_NOT_AVAILABLE`` - it failed to measure it, or the 220 measurement was not complete yet. 221 222 - ``FE_SCALE_COUNTER`` - Number of error blocks counted after the outer 223 coding. 224 225 226 .. _DTV-STAT-TOTAL-BLOCK-COUNT: 227 228 DTV-STAT_TOTAL_BLOCK_COUNT 229 ========================== 230 231 Measures the total number of blocks received during the same period as 232 :ref:`DTV_STAT_ERROR_BLOCK_COUNT <DTV-STAT-ERROR-BLOCK-COUNT>` 233 measurement was taken. 234 235 It can be used to calculate the PER indicator, by dividing 236 :ref:`DTV_STAT_ERROR_BLOCK_COUNT <DTV-STAT-ERROR-BLOCK-COUNT>` by 237 :ref:`DTV-STAT-TOTAL-BLOCK-COUNT`. 238 239 Possible scales for this metric are: 240 241 - ``FE_SCALE_NOT_AVAILABLE`` - it failed to measure it, or the 242 measurement was not complete yet. 243 244 - ``FE_SCALE_COUNTER`` - Number of blocks counted while measuring 245 :ref:`DTV_STAT_ERROR_BLOCK_COUNT <DTV-STAT-ERROR-BLOCK-COUNT>`.
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