tda9874aps NXP Semiconductors, tda9874aps Datasheet - Page 48

• Manufacturer Part Number: tda9874aps
• Description: Digital Tv Sound Demodulator/decoder
• Manufacturer: NXP Semiconductors

Philips Semiconductors
7.4.5
These two bytes constitute a word that provides data from
a location that has been specified with the monitor select
register (see Section 7.3.4). The most significant byte of
the data is stored at subaddress 5.
Table 82 Level read-out register A (subaddress 5)
Note
1. B7 is the most significant bit or sign bit of the word.
Table 83 Level read-out register B (subaddress 6)
Note
1. B0 is the least significant bit of the word.
7.4.6
When the SIF AGC is on, bits B4 to B0 of this register
contain a number that gives an indication of the SIF input
level. That number can be interpreted in the same way as
the AGC gain register setting (see Section 7.3.2), i.e. if the
SIF AGC were set to a fixed gain and the same number
loaded into the AGC gain register, the current SIF input
signal level would generate a SIF ADC output close to
full-scale.
When the SIF AGC is off, this register returns the contents
of the AGC gain register.
Bits B5 and B6 are don’t care.
2000 Aug 04
B7
B7
Digital TV sound demodulator/decoder
7
7
(1)
L
SIF L
B6
B6
6
6
EVEL
EVEL
R
B5
B5
EAD
5
5
R
-
EGISTER
OUT
B4
B4
4
4
R
EGISTERS
(SIFLR)
B3
B3
3
3
(LRRA
B2
B2
2
2
AND
B1
B1
1
1
LRRB)
B0
B0
0
0
(1)
48
Table 84 SIF level register (subaddress 7)
Table 85 Description of the SIF level register bits
Note
1. The pilot detector is faster than the stereo/dual
IDPILOT
identification, but not as reliable and slightly less
sensitive. By means of the pilot detector bit, the control
software is able to identify an analog 2-carrier (A2)
standard transmission within approximately 0.1 s and
even in the event of a mono transmission (second
sound carrier with pilot). Certain NICAM test signals
may trigger a wrong pilot indication, therefore the pilot
detector bit should not be evaluated at channel 2 mixer
frequencies that correspond to NICAM carriers
(5.85 and 6.552 MHz). For detailed information,
please contact a Philips representative.
BIT
7
7
6
5
4
3
2
1
0
SYMBOL
IDPILOT
6
B4
B3
B2
B1
B0
5
Bit IDPILOT: if this bit is logic 1
it indicates that an FM pilot
carrier in the 2nd channel is
detected; note 1
this bit is undefined
this bit is undefined
SIF level data bits: these bits
correspond to the input level at
the selected SIF input
B4
4
B3
DESCRIPTION
3
Product specification
TDA9874A
B2
2
B1
1
B0
0