TDA9874H datasheet(24/56 Pages) PHILIPS

24 / 56 page

1998 Apr 27

Philips Semiconductors

Preliminary speciﬁcation

Digital TV sound demodulator/decoder

TDA9874H

Changing the FM identification mode during FM reception may cause a brief flickering of bit IDSTE or 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 9), it is

recommended to set the TIMPOL bit HIGH (write subaddress 14; see Section 7.3.11) for best S/N performance.

7.3.7

FM DE-EMPHASIS REGISTER (FMDR)

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 10001000.

Table 26 FM De-emphasis Register (subaddress 10)

Table 27 Description of FMDR bits

Table 28 De-emphasis

Note

1. The FM de-emphasis gain is 0 dB at 40 Hz.

76543210

ADEEM2

FMDSC23

FMDSC22

FMDSC21

ADEEM1

FMDSC13

FMDSC12

FMDSC11

BIT

SYMBOL

DESCRIPTION

ADEEM2

Adaptive de-emphasis on/off. 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

µs.

ADEEM2 = 0, the adaptive de-emphasis is off.

FMDSC23

FM de-emphasis. The state of these 3 bits determine the FM de-emphasis for sound

carrier 2; see Table 28.

FMDSC22

FMDSC21

ADEEM1

Adaptive de-emphasis on/off. 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

µs.

ADEEM1 = 0, the adaptive de-emphasis is off.

FMDSC13

FM de-emphasis. The state of these 3 bits determine the FM de-emphasis for sound

carrier 1; see Table 28.

FMDSC12

FMDSC11

FMDSC23

FMDSC22

FMDSC21

DE-EMPHASIS(1)

FMDSC13

FMDSC12

FMDSC11

000

µs

001

µs

010

µs

011

J17

100

off

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