-#ifdef SNR_IN_DB
- /*
- * Spec sheet shows formula for SNR_EQ = 10 log10(25 * 24**2 / noise)
- * and SNR_PH = 10 log10(25 * 32**2 / noise) for equalizer and phase tracker
- * respectively. The following tables are built on these formulas.
- * The usual definition is SNR = 20 log10(signal/noise)
- * If the specification is wrong the value retuned is 1/2 the actual SNR in db.
- *
- * This table is a an ordered list of noise values computed by the
- * formula from the spec sheet such that the index into the table
- * starting at 43 or 45 is the SNR value in db. There are duplicate noise
- * value entries at the beginning because the SNR varies more than
- * 1 db for a change of 1 digit in noise at very small values of noise.
- *
- * Examples from SNR_EQ table:
- * noise SNR
- * 0 43
- * 1 42
- * 2 39
- * 3 37
- * 4 36
- * 5 35
- * 6 34
- * 7 33
- * 8 33
- * 9 32
- * 10 32
- * 11 31
- * 12 31
- * 13 30
- */
-
- static const u32 SNR_EQ[] =
- { 1, 2, 2, 2, 3, 3, 4, 4, 5, 7,
- 9, 11, 13, 17, 21, 26, 33, 41, 52, 65,
- 81, 102, 129, 162, 204, 257, 323, 406, 511, 644,
- 810, 1020, 1284, 1616, 2035, 2561, 3224, 4059, 5110, 6433,
- 8098, 10195, 12835, 16158, 20341, 25608, 32238, 40585, 51094, 64323,
- 80978, 101945, 128341, 161571, 203406, 256073, 0x40000
- };
-
- static const u32 SNR_PH[] =
- { 1, 2, 2, 2, 3, 3, 4, 5, 6, 8,
- 10, 12, 15, 19, 23, 29, 37, 46, 58, 73,
- 91, 115, 144, 182, 229, 288, 362, 456, 574, 722,
- 909, 1144, 1440, 1813, 2282, 2873, 3617, 4553, 5732, 7216,
- 9084, 11436, 14396, 18124, 22817, 28724, 36161, 45524, 57312, 72151,
- 90833, 114351, 143960, 181235, 228161, 0x080000
- };
-
- static u8 buf[5];/* read data buffer */
- static u32 noise; /* noise value */
- static u32 snr_db; /* index into SNR_EQ[] */