MSP3410B Просмотр технического описания (PDF) - Micronas
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MSP3410B Datasheet PDF : 68 Pages
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MSP 3410 B
PRELIMINARY DATA SHEET
3. Application Fields of the MSP 3410 B
In the following sections, a brief overview about the two
main TV sound standards, NICAM 728 and German FM-
Stereo, demonstrates the complex requirements of a
multistandard audio IC.
3.1. NICAM plus FM-Mono
According to the British, Scandinavian and Spanish TV-
standards, high quality stereo sound is transmitted digi-
tally. The systems allow two high quality digital sound
channels to be added to the already existing FM chan-
nel. The sound coding follows the format of the so-called
Near Instantaneous Companding System (NICAM 728).
Transmission is performed using Differential Quadra-
ture Phase Shift Keying (DQPSK). Table 3–2 gives
some specifications of the sound coding (NICAM); Table
3–3 offers an overview of the modulation parameters.
In the case of NICAM/FM mode there are three different
audio channels available: NICAM A,NICAM B and FM-
mono. NICAM A and B may belong either to a stereo or
to a dual language transmission. Information about op-
eration mode and about the quality of the NICAM signal
can be read by the CCU via the control bus. In the case
of low quality (high bit error rate) the CCU may decide
to switch to the analog FM-mono sound.
3.2. German 2-Carrier System (DUAL FM System)
Since September 1981, stereo and dual sound pro-
grams have been transmitted in Germany using the
2-carrier system. Sound transmission consists of the al-
ready existing first sound carrier and a second sound
carrier additionally containing an identification signal.
Some more details of this standard are given in Table
3–4.
Table 3–1: European TV standards
TV-System
B/G
B/G
L
I
D,K
M
Satellite
Satellite
Position of Sound
Carrier /MHz
5.5/5.74
5.5/5.85
6.5/5.85
6.0/6.552
6.5
4.5
6.5
7.02/7.2
Sound
Modulation
FM-Stereo
FM-Mono/NICAM
AM-Mono/NICAM
FM-Mono/NICAM
FM-Mono
FM-Mono
FM-Mono
FM-Stereo
Color System
PAL
PAL
SECAM
PAL
SECAM
NTSC
PAL
PAL
Country
Germany
Scandinavia,Spain
France
UK
USSR
USA
Europe (ASTRA)
Europe (ASTRA)
Table 3–2: Summary of NICAM 728 sound coding characteristics
Characteristics
Audio sampling frequency
Number of channels
Initial resolution
Companding characteristics
Coding for compressed samples
Preemphasis
Audio overload level
Values
32 kHz
2
14 bit/sample
near instantaneous, with compression to 10 bits/sample in 32-sam-
ples (1 ms) blocks
2’s complement
CCITT Recommendation J.17 (6.5 dB attenuation at 800 Hz)
+12 dBm0 measured at the unity gain frequency of the preemphasis
network (2 kHz)
6
ITT Semiconductors
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