tda9874aps NXP Semiconductors, tda9874aps Datasheet - Page 27

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

Philips Semiconductors
Table 28 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
7.3.8
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 29 FM de-emphasis register (subaddress 10)
Table 30 Description of the FM de-emphasis register bits
2000 Aug 04
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
DE
-
EMPHASIS REGISTER
FMDSC23
FMDSC23
FMDSC22
FMDSC21
FMDSC13
FMDSC12
FMDSC11
FILTBW0
SYMBOL
ADEEM1
ADEEM2
0
1
0
1
6
Adaptive de-emphasis on/off sound carrier 2: if bit 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.
If bit ADEEM2 = 0 the adaptive de-emphasis is off.
FM de-emphasis: the state of these bits determines the FM de-emphasis for sound
carrier 2; see Table 31.
Adaptive de-emphasis on/off sound carrier 1: if bit 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.
If bit ADEEM1 = 0 the adaptive de-emphasis is off.
FM de-emphasis: the state of these bits determines the FM de-emphasis for sound
carrier 1; see Table 31.
CHANNEL 1
FMDSC22
extra wide
medium
narrow
FILTER BANDWIDTH
wide
5
FMDSC21
CHANNEL 2
medium
narrow
narrow
4
wide
27
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
1
Product specification
TDA9874A
FMDSC11
0