diff options
| -rw-r--r-- | drivers/media/dvb-frontends/dib7000p.c | 54 |
1 files changed, 47 insertions, 7 deletions
diff --git a/drivers/media/dvb-frontends/dib7000p.c b/drivers/media/dvb-frontends/dib7000p.c index c41f90da6e1..661760d6023 100644 --- a/drivers/media/dvb-frontends/dib7000p.c +++ b/drivers/media/dvb-frontends/dib7000p.c @@ -1693,13 +1693,56 @@ struct linear_segments { * This table should be empirically determinated by measuring the signal * strength generated by a RF generator directly connected into * a device. + * This table was determinated by measuring the signal strength generated + * by a DTA-2111 RF generator directly connected into a dib7000p device + * (a Hauppauge Nova-TD stick), using a good quality 3 meters length + * RC6 cable and good RC6 connectors, connected directly to antenna 1. + * As the minimum output power of DTA-2111 is -31dBm, a 16 dBm attenuator + * were used, for the lower power values. + * The real value can actually be on other devices, or even at the + * second antena input, depending on several factors, like if LNA + * is enabled or not, if diversity is enabled, type of connectors, etc. + * Yet, it is better to use this measure in dB than a random non-linear + * percentage value, especially for antenna adjustments. + * On my tests, the precision of the measure using this table is about + * 0.5 dB, with sounds reasonable enough to adjust antennas. */ -/* FIXME: Calibrate the table */ - -#define DB_OFFSET 0 +#define DB_OFFSET 131000 static struct linear_segments strength_to_db_table[] = { - { 65535, 65535}, + { 63630, DB_OFFSET - 20500}, + { 62273, DB_OFFSET - 21000}, + { 60162, DB_OFFSET - 22000}, + { 58730, DB_OFFSET - 23000}, + { 58294, DB_OFFSET - 24000}, + { 57778, DB_OFFSET - 25000}, + { 57320, DB_OFFSET - 26000}, + { 56779, DB_OFFSET - 27000}, + { 56293, DB_OFFSET - 28000}, + { 55724, DB_OFFSET - 29000}, + { 55145, DB_OFFSET - 30000}, + { 54680, DB_OFFSET - 31000}, + { 54293, DB_OFFSET - 32000}, + { 53813, DB_OFFSET - 33000}, + { 53427, DB_OFFSET - 34000}, + { 52981, DB_OFFSET - 35000}, + + { 52636, DB_OFFSET - 36000}, + { 52014, DB_OFFSET - 37000}, + { 51674, DB_OFFSET - 38000}, + { 50692, DB_OFFSET - 39000}, + { 49824, DB_OFFSET - 40000}, + { 49052, DB_OFFSET - 41000}, + { 48436, DB_OFFSET - 42000}, + { 47836, DB_OFFSET - 43000}, + { 47368, DB_OFFSET - 44000}, + { 46468, DB_OFFSET - 45000}, + { 45597, DB_OFFSET - 46000}, + { 44586, DB_OFFSET - 47000}, + { 43667, DB_OFFSET - 48000}, + { 42673, DB_OFFSET - 49000}, + { 41816, DB_OFFSET - 50000}, + { 40876, DB_OFFSET - 51000}, { 0, 0}, }; @@ -1853,9 +1896,6 @@ static int dib7000p_get_stats(struct dvb_frontend *demod, fe_status_t stat) ARRAY_SIZE(strength_to_db_table)) - DB_OFFSET; c->strength.stat[0].svalue = db; - /* FIXME: Remove this when calibrated to DB */ - c->strength.stat[0].scale = FE_SCALE_COUNTER; - /* UCB/BER/CNR measures require lock */ if (!(stat & FE_HAS_LOCK)) { c->cnr.len = 1; |