TDA9874A Philips Semiconductors, TDA9874A Datasheet - Page 35

• Manufacturer Part Number: TDA9874A
• Description: Digital TV sound demodulator/decoder
• Manufacturer: Philips Semiconductors

Philips Semiconductors
Table 30 Filter bandwidth for channel 1 and channel 2; note 1
Note
1. It is recommended to switch the FM sound mode identification off whenever the received program is not a terrestrial
10.3.8
This register should not be used when applying ESP. This register is used to select the proper de-emphasis
characteristics as appropriate for the standard of the received carrier. Bits 3 to 0 apply to sound carrier 1, bits 7 to 4 apply
to sound carrier 2. In the event of A2 reception, both groups must be set to the same characteristics.
The default setting after power-on reset is ‘0000 0000’.
Table 31 FM De-emphasis register (subaddress 10)
Table 32 Description of the FMDR bits
1999 Dec 03
Digital TV sound demodulator/decoder
FILTBW1
ADEEM2
2-carrier sound. Switching the identification off will reset the associated hardware to a defined state.
BIT
0
0
1
1
7
7
6
5
4
3
2
1
0
FM D
E
-
EMPHASIS
FMDSC23
FMDSC23
FMDSC22
FMDSC21
FMDSC13
FMDSC12
FMDSC11
FILTBW0
SYMBOL
ADEEM1
ADEEM2
0
1
0
1
6
R
EGISTER
Adaptive de-emphasis on/off sound carrier 2: when ADEEM2 = 1 it activates the
adaptive de-emphasis function (for Wegener-Panda 1 encoded programs), which is
required for certain satellite FM channels. The standard FM de-emphasis must then be
set to 75 s. When ADEEM2 = 0, the adaptive de-emphasis is off.
FM de-emphasis: the state of these 3 bits determines the FM de-emphasis for sound
carrier 2; see Table 33.
Adaptive de-emphasis on/off sound carrier 1: when ADEEM1 = 1 it activates the
adaptive de-emphasis function (for Wegener-Panda 1 encoded programs), which is
required for certain satellite FM channels. The standard FM de-emphasis must then be
set to 75 s. When ADEEM1 = 0, the adaptive de-emphasis is off.
FM de-emphasis: the state of these 3 bits determines the FM de-emphasis for sound
carrier 1; see Table 33.
CHANNEL 1
FMDSC22
extra wide
medium
narrow
FILTER BANDWIDTH
wide
5
(FMDR)
FMDSC21
CHANNEL 2
medium
narrow
narrow
4
wide
35
ADEEM1
Recommended for nominal terrestrial broadcast
conditions and SAT with 2 carriers
Recommended for highly overmodulated single FM
carriers. Only channel 1 is available for FM
demodulation in this mode. NICAM can still be
processed on channel 2.
Recommended for moderately overmodulated
broadcast conditions
Recommended for strongly overmodulated broadcast
conditions
3
DESCRIPTION
FMDSC13
2
FILTER MODES
FMDSC12
Preliminary specification
1
TDA9874A
FMDSC11
0