MSP3421G MICRONAS [Micronas], MSP3421G Datasheet - Page 10

• Manufacturer Part Number: MSP3421G
• Description: Multistandard Sound Processor Family with Virtual Dolby Surround
• Manufacturer: MICRONAS [Micronas]

MSP 34x1G
2.1. Architecture of the MSP 34x1G Family
Fig. 2–1 on page 9 shows a simplified block diagram of
the IC. The block diagram contains all features of the
MSP 3451G. Other members of the MSP 34x1G family
do not have the complete set of features: The demodu-
lator handles only a subset of the standards presented
in the demodulator block; NICAM processing is only
possible in the MSP 3411G and MSP 3451G.
2.2. Sound IF Processing
2.2.1. Analog Sound IF Input
The input pins ANA_IN1+, ANA_IN2+, and ANA_IN
offer the possibility to connect two different sound IF
(SIF) sources to the MSP 34x1G. The analog-to-digital
conversion of the preselected sound IF signal is done
by an A/D-converter. An analog automatic gain circuit
(AGC) allows a wide range of input levels. The high-
pass filters formed by the coupling capacitors at pins
ANA_IN1+ and ANA_IN2+ see Section 8. “Appendix
E: Application Circuit” on page 103 are sufficient in
most cases to suppress video components. Some
combinations of SAW filters and sound IF mixer ICs,
however, show large picture components on their out-
puts. In this case, further filtering is recommended.
2.2.2. Demodulator: Standards and Features
The MSP 34x1G is able to demodulate all TV-sound
standards worldwide including the digital NICAM sys-
tem. Depending on the MSP 34x1G version, the fol-
lowing demodulation modes can be performed:
A2 Systems: Detection and demodulation of two sep-
arate FM carriers (FM1 and FM2), demodulation and
evaluation of the identification signal of carrier FM2.
NICAM Systems: Demodulation and decoding of the
NICAM carrier, detection and demodulation of the ana-
log (FM or AM) carrier. For D/K-NICAM, the FM carrier
may have a maximum deviation of 384 kHz.
Very high deviation FM-Mono: Detection and robust
demodulation of one FM carrier with a maximum devi-
ation of 540 kHz.
BTSC-Stereo: Detection and FM demodulation of the
aural carrier resulting in the MTS/MPX signal. Detec-
tion and evaluation of the pilot carrier, AM demodula-
tion of the (L R)-carrier and detection of the SAP sub-
carrier. Processing of DBX noise reduction or Micronas
Noise Reduction (MNR).
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BTSC-Mono + SAP: Detection and FM demodulation
of the aural carrier resulting in the MTS/MPX signal.
Detection and evaluation of the pilot carrier, detection
and FM demodulation of the SAP subcarrier. Process-
ing of DBX noise reduction or Micronas Noise Reduc-
tion (MNR).
Japan Stereo: Detection and FM demodulation of the
aural carrier resulting in the MPX signal. Demodulation
and evaluation of the identification signal and FM
demodulation of the (L R)-carrier.
FM-Satellite Sound: Demodulation of one or two FM
carriers. Processing of high-deviation mono or narrow
bandwidth mono, stereo, or bilingual satellite sound
according to the ASTRA specification.
FM-Stereo-Radio: Detection and FM demodulation of
the aural carrier resulting in the MPX signal. Detection
and evaluation of the pilot carrier and AM demodula-
tion of the (L R)-carrier.
The demodulator blocks of all MSP 34x1G versions
have identical user interfaces. Even completely differ-
ent systems like the BTSC and NICAM systems are
controlled the same way. Standards are selected by
means of MSP Standard Codes. Automatic processes
handle standard detection and identification without
controller interaction. The key features of the
MSP 34x1G demodulator blocks are
Standard Selection: The controlling of the demodula-
tor is minimized: All parameters, such as tuning fre-
quencies or filter bandwidth, are adjusted automati-
cally by transmitting one single value to the
STANDARD SELECT register. For all standards, spe-
cific MSP standard codes are defined.
Automatic Standard Detection: If the TV sound stan-
dard is unknown, the MSP 34x1G can automatically
detect the actual standard, switch to that standard, and
respond the actual MSP standard code.
Automatic Carrier Mute: To prevent noise effects or
FM identification problems in the absence of an FM
carrier, the MSP 34x1G offers a configurable carrier
mute feature, which is activated automatically if the TV
sound standard is selected by means of the STAN-
DARD SELECT register. If no FM carrier is detected at
one of the two MSP demodulator channels, the corre-
sponding demodulator output is muted. This is indi-
cated in the STATUS register.
PRELIMINARY DATA SHEET
Micronas