1999 Dec 03
3
Philips Semiconductors
Preliminary specification
Digital TV sound demodulator/decoder
TDA9874A
1
FEATURES
Sound IF (SIF) input switch
SIF AGC with 24 dB control range
Switchable 10 dB SIF input attenuator
SIF 8-bit Analog-to-Digital Converter (ADC)
Easy TV standard programming option
Differential Quadrature Phase Shift Keying (DQPSK)
demodulation for different standards, simultaneously
with 1-channel FM demodulation
NICAM decoding (B/G, D/K, I and L standard)
2-carrier multi-standard FM demodulation (B/G, D/K and
M standard)
Single carrier high deviation FM mono demodulation
mode
Decoding for three analog multi-channel systems (A2)
and satellite sound
Adaptive de-emphasis for satellite
Programmable identification (B/G, D/K and M standard)
and different identification times
FM pilot carrier presence detector
Optional AM demodulation for system L, simultaneously
with NICAM
Monitor selection for FM/AM demodulator outputs and
FM and NICAM signals with peak option
Automatic FM dematrixing option
Digital crossbar switch
I
2
S-bus serial audio output with matrix, level adjustment
and mute
Dual audio Digital-to-Analog Converter (DAC) from
digital crossbar switch to analog crossbar switch,
bandwidth = 15 kHz
Automatic Volume Level (AVL) control
Analog crossbar switch with inputs for mono and stereo
Output selection of mono, stereo, dual, dual A or dual B
Additional mono output with automatic select
20 kHz bandwidth for analog path
Standby mode
Automatic output selection for TV applications.
2
GENERAL DESCRIPTION
The TDA9874A is a single-chip Digital TV Sound
Demodulator/Decoder (DTVSD) for analog and digital
multi-channel sound systems in TV/VCR sets and satellite
receivers.
2.1
Supported standards
The multi-standard/multi-stereo capability of the
TDA9874A is of interest in Europe, Hong Kong/PR China
and South East Asia. This includes B/G, D/K, I, M and
L standard. In other application areas subsets of the
standard combinations are available or, only single
standards are transmitted.
All A2 (analog 2-carrier) and NICAM systems are
supported. M standard (with mono or BTSC stereo sound)
can be received and processed in mono sound mode.
The AM sound of L/L' standard is normally demodulated in
the 1st sound IF. The resulting AF signal has to be entered
into the mono audio input of the TDA9874A. A second
possibility is to use the internal AM demodulator stage
(with 6.5 MHz intercarrier), which gives limited
performance.
Korea has a stereo sound system similar to Europe and is
supported by the TDA9874A. The differences include
deviation, modulation contents and identification. It is
based on M standard.
For all FM standards a high deviation mode for a single
carrier monaural sound demodulation is selectable.
An overview of the supported standards and sound
systems and their key parameters is given in
Tables 1 to 3.
The analog multi-channel systems are sometimes also
called 2CS (2-carrier systems).
1999 Dec 03
4
Philips Semiconductors
Preliminary specification
Digital TV sound demodulator/decoder
TDA9874A
2.1.1
A
NALOG
2-
CARRIER SYSTEMS
Table 1
Frequency modulation
Table 2
Identification for A2 systems
2.1.2
2-
CARRIER SYSTEMS WITH
NICAM
Table 3
NICAM
Notes
1. See
"EBU NICAM 728 specification" or equivalent specification.
2. Not yet officially defined.
STANDARD
SOUND
SYSTEM
CARRIER
FREQUENCY
(MHz)
FM DEVIATION (kHz)
MODULATION
BANDWIDTH/
DE-EMPHASIS
(kHz/
s)
NOM.
MAX.
OVER.
SC1
SC2
M
mono
4.5
15
25
50
mono
-
15/75
M
A2
4.5/4.724
15
25
50
1
/
2
(L + R)
1
/
2
(L
-
R)
15/75 (Korea)
B/G
A2
5.5/5.742
27
50
80
1
/
2
(L + R)
R
15/50
I
mono
6.0
27
50
80
mono
-
15/50
D/K (2)
A2
6.5/6.742
27
50
80
1
/
2
(L + R)
R
15/50
D/K (1)
A2
6.5/6.258
27
50
80
1
/
2
(L + R)
R
15/50
D/K (3)
A2
6.5/5.742
27
50
80
1
/
2
(L + R)
R
15/50
PARAMETER
A2; A2*
A2+ (KOREA)
Pilot frequency
54.6875 kHz = 3.5
line frequency
55.0699 kHz = 3.5
line frequency
Stereo identification frequency
Dual identification frequency
AM modulation depth
50%
50%
STANDARD
SC1
SC2
(MHz)
NICAM
DE-
EMPHASIS
ROLL-
OFF (%)
NICAM
CODING
FREQUENCY
(MHz)
TYPE
MODULATION
INDEX (%)
DEVIATION
(kHz)
NOM.
MAX.
NOM.
MAX.
B/G
5.5
FM
-
-
27
50
5.85
J17
40
note 1
I
6.0
FM
-
-
27
50
6.552
J17
100
note 1
D/K
6.5
FM
-
-
27
50
5.85
J17
40
note 2
L
6.5
AM
54
100
-
-
5.85
J17
40
note 1
117.5 Hz
line frequency
133
---------------------------------------
=
149.9 Hz
line frequency
105
---------------------------------------
=
274.1 Hz
line frequency
57
---------------------------------------
=
276.0 Hz
line frequency
57
---------------------------------------
=
1999 Dec 03
5
Philips Semiconductors
Preliminary specification
Digital TV sound demodulator/decoder
TDA9874A
2.1.3
S
ATELLITE SYSTEMS
An important specification for satellite TV reception is the Astra specification. The TDA9874A is suitable for the reception
of Astra and other satellite signals, with sound carrier frequencies from 4 to 9.2 MHz.
Table 4
FM satellite sound
Notes
1. For other satellite systems, frequencies of e.g. 5.80, 6.60 or 6.65 MHz can also be received. A de-emphasis of 60
s,
or in accordance with J17, is available.
2. Main channels with high deviation can also be handled.
3. m/st/d = mono or stereo or dual language sound.
4. Adaptive de-emphasis is compatible to transmitter specification.
3
ORDERING INFORMATION
CARRIER TYPE
CARRIER
FREQUENCY
(MHz)
MODULATION
INDEX
MAXIMUM
FM DEVIATION
(kHz)
MODULATION
BANDWIDTH/
DE-EMPHASIS
(kHz/
s)
Main
6.50
(1)
0.26
85
(2)
mono
15/50
(1)
Sub
7.02/7.20
0.15
50
m/st/d
(3)
15/adaptive
(4)
7.38/7.56
7.74/7.92
8.10/8.28
TYPE NUMBER
PACKAGE
NAME
DESCRIPTION
VERSION
TDA9874APS
SDIP42
plastic shrink dual in-line package; 42 leads (600 mil)
SOT270-1
TDA9874AH
QFP44
plastic quad flat package; 44 leads (lead length 2.35 mm);
body 14
14
2.2 mm
SOT205-1
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