tda9874h NXP Semiconductors, tda9874h Datasheet - Page 23

• Manufacturer Part Number: tda9874h
• Description: Digital Tv Sound Demodulator/decoder
• Manufacturer: NXP Semiconductors

Philips Semiconductors
Changing the FM identification mode during FM reception may cause a brief flickering of bit IDSTE or bit IDDUA in the
device status register (see Section 7.4.1).
When channel 2 is used to receive FM sound carriers with the current application proposal (see Chapter 12), it is
recommended to set bit TIMPOL to logic 1 (write subaddress 14; see Section 7.3.11) for best S/N performance.
7.3.7
This register is used to select the proper de-emphasis characteristics as appropriate for the standard of the received
carrier. Bits B3 to B0 apply to sound carrier 1, bits B7 to B4 apply to sound carrier 2. In the event of A2 reception, both
groups must be set to the same characteristics.
The default setting at power-up is 1000 1000.
Table 25 FM de-emphasis register (subaddress 10)
Table 26 Description of the FM de-emphasis register bits
Table 27 De-emphasis
Note
1. The FM de-emphasis gain is 0 dB at 40 Hz.
2000 Jun 26
FMDSC23
FMDSC13
Digital TV sound demodulator/decoder
ADEEM2
BIT
7
7
6
5
4
3
2
1
0
0
0
0
0
1
FM
DE
-
EMPHASIS REGISTER
FMDSC23
FMDSC23
FMDSC22
FMDSC21
FMDSC13
FMDSC12
FMDSC11
FMDSC22
FMDSC12
SYMBOL
ADEEM1
ADEEM2
6
0
0
1
1
0
Adaptive de-emphasis on/off: bit ADEEM2 = 1 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 determine the FM de-emphasis for sound
carrier 2 (see Table 27).
Adaptive de-emphasis on/off: bit ADEEM1 = 1 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 determine the FM de-emphasis for sound
carrier 1 (see Table 27).
FMDSC22
FMDSC21
FMDSC11
5
0
1
0
1
0
FMDSC21
4
23
ADEEM1
3
DESCRIPTION
DE-EMPHASIS
FMDSC13
50 s
60 s
75 s
J17
off
2
(1)
FMDSC12
1
Product specification
TDA9874H
FMDSC11
0