XOCECO LC-27R18, Service Manual

Page: 10 / 42

8
IC block diagram
1.MSP3420
The MSP 34x0G family of single-chip Multistandard Sound Processors covers the sound
processing of all analog TV-Standards worldwide, as well as the NICAM digital sound standards.
The full TV sound processing, starting with analog sound IF signal-in, down to processed analog
AF-out, is performed on a single chip. Figure 1–1 shows a simplified functional block diagram of the
MSP 34x0G.
This new generation of TV sound processing ICs now includes versions for processing the
multichannel television sound (MTS) signal conforming to the standard recommended by the
Broadcast Television Systems Committee (BTSC). The DBX noise reduction, or alternatively,
Micronas Noise Reduction (MNR) is performed alignment free.
Other processed standards are the Japanese FM-FM multiplex standard (EIA-J) and the FM Stereo
Radio standard.
Current ICs have to perform adjustment procedures in order to achieve good stereo separation for
BTSC and EIA-J. The MSP 34x0G has optimum stereo performance without any adjustments.
All MSP 34xxG versions are pin compatible to the MSP 34xxD. Only minor modifications are
necessary to adapt a MSP34xxD controlling software to the MSP 34xxG. The MSP 34x0G further
simplifies controlling software. Standard selection requires a single I2C transmission only.
The MSP 34x0G has built-in automatic functions: The IC is able to detect the actual sound standard
automatically (Automatic Standard Detection). Furthermore, pilot levels and identification signals
can be evaluated internally with subsequent switching between mono/ stereo/bilingual; no I2C
interaction is necessary (Automatic Sound Selection).
The MSP 34x0G can handle very high FM deviations even in conjunction with NICAM processing.
This is especially important for the introduction of NICAM in China.
The ICs are produced in submicron CMOS technology. The MSP 34x0G is available in the following
packages: PLCC68 (not intended for new design), PSDIP64, PSDIP52, PQFP80, and PLQFP64.