tree 51040df3d3f76e4f15ab274b6e4682e81033e36e
parent e58f1d39e1bbb5a81572b4838d02bb89247e9c15
author Ke Dong <kedong@google.com> 1425027262 -0800
committer Ke Dong <kedong@google.com> 1425535339 -0800

Correct the signal strength calculation.

The current signal strength calculation does not consider the
baseband power and the compensation gain. Since the dvb callback
only takes unsigned int, the return value is always positive. The
application needs to negate the value if needed.

Test:

Set the signal generator to -30dbm, plus the cable loss and connector loss.
The result is 32dbm.

SPACECAST2# dvbsnoop -s signal -pd 9
dvbsnoop V1.4.50 -- http://dvbsnoop.sourceforge.net/
   DEMUX : /dev/dvb/adapter0/demux0
   DVR   : /dev/dvb/adapter0/dvr0
   FRONTEND: /dev/dvb/adapter0/frontend0

---------------------------------------------------------
Transponder/Frequency signal strength statistics...
Capabilities: BER: 1  SNR: 1  SIG: 1  STAT: 1  UBLK: 1
---------------------------------------------------------
cycle: 1  d_time: 0.001 s  Sig: 32  SNR: 14  BER: 0  UBLK: 0  Stat: 0x1f [SIG CARR VIT SYNC LOCK ]
cycle: 2  d_time: 0.013 s  Sig: 32  SNR: 14  BER: 0  UBLK: 0  Stat: 0x1f [SIG CARR VIT SYNC LOCK ]
cycle: 3  d_time: 0.012 s  Sig: 32  SNR: 14  BER: 0  UBLK: 0  Stat: 0x1f [SIG CARR VIT SYNC LOCK ]
cycle: 4  d_time: 0.012 s  Sig: 32  SNR: 14  BER: 0  UBLK: 0  Stat: 0x1f [SIG CARR VIT SYNC LOCK ]
cycle: 5  d_time: 0.012 s  Sig: 32  SNR: 14  BER: 0  UBLK: 0  Stat: 0x1f [SIG CARR VIT SYNC LOCK ]
cycle: 6  d_time: 0.013 s  Sig: 32  SNR: 14  BER: 0  UBLK: 0  Stat: 0x1f [SIG CARR VIT SYNC LOCK ]

Google-Bug-Id: 19432272
Change-Id: I7d5c83c1a89a1b16d57e411374d5c13bd55c0f98