Philips Semiconductors
Preliminary specification
Digital TV sound demodulator/decoder
1
FEATURES
TDA9874A
•
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
3
Philips Semiconductors
Preliminary specification
Digital TV sound demodulator/decoder
2.1.3
S
ATELLITE SYSTEMS
TDA9874A
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
CARRIER
FREQUENCY
(MHz)
6.50
(1)
7.02/7.20
7.38/7.56
7.74/7.92
8.10/8.28
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
µs,
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
PACKAGE
TYPE NUMBER
NAME
TDA9874APS
TDA9874AH
SDIP42
QFP44
DESCRIPTION
plastic shrink dual in-line package; 42 leads (600 mil)
plastic quad flat package; 44 leads (lead length 2.35 mm);
body 14
×
14
×
2.2 mm
VERSION
SOT270-1
SOT205-1
MODULATION
INDEX
0.26
0.15
MAXIMUM
FM DEVIATION
(kHz)
85
(2)
50
MODULATION
mono
m/st/d
(3)
BANDWIDTH/
DE-EMPHASIS
(kHz/µs)
15/50
(1)
15/adaptive
(4)
CARRIER TYPE
Main
Sub
1999 Dec 03
5
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