PRELIMINARY DATA SHEET
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 the DBX noise reduction or Micronas Noise
Reduction (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 34x7G 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 34x7G 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 34x7G 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 34x7G 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.
2.1. Architecture of the MSP 34x7G Family
the IC. The block diagram contains all features of the
MSP 3457G. Other members of the MSP 34x7G 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 3417G and MSP 3457G (see
dashed block in Fig. 2–1).
2.2. Sound IF Processing
2.2.1. Analog Sound IF Input
The input pins ANA_IN1+ and ANA_IN
−
offer the pos-
sibility to connect sound IF (SIF) sources to the
MSP 34x7G. The analog-to-digital conversion of the
sound IF signal is done by an A/D-converter. An ana-
log automatic gain circuit (AGC) allows a wide range of
input levels. The high-pass filter formed by the cou-
pling capacitor at pin ANA_IN1+ (see Section 7.
sufficient in most cases to suppress video compo-
nents. Some combinations of SAW filters and sound IF
mixer ICs, however, show large picture components on
their outputs. In this case, further filtering is recom-
mended.
2.2.2. Demodulator: Standards and Features
The MSP 34x7G is able to demodulate all TV sound
standards worldwide including the digital NICAM sys-
tem. Depending on the MSP 34x7G 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 the DBX noise reduction or
Micronas Noise Reduction (MNR).
Micronas
9
MICRONAS [ MICRONAS ]
