MSP3410B Datasheet, PDF(11/68 Page) Micronas – Multistandard Sound Processor

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MSP3410B Datasheet, PDF (11/68 Pages) Micronas – Multistandard Sound Processor

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PRELIMINARY DATA SHEET

MSP 3410 B

4.1.8. MSP-Mute Function in the Dual Carrier FM

Mode

To prevent noise effects or FM identification problems in

the absence of one of the two FM carriers the MSP 3410

B offers a carrier detection feature, which must be acti-

vated by means of AD_CV[9], see section 11.2.1. If no

FM carrier is available at the MSP channel 1, the corre-

sponding channel FM2 (and S-Bus output samples 3

and 4) are muted. If no FM carrier is available at the MSP

channel 2, the corresponding channel FM1 (and S-Bus

output samples 1 and 2) are muted. In case of the ab-

sence of both FM carriers pure noise will be amplified by

the input AGC. Therefore a proper mute function de-

pends on the noise quality of the TV setâs IF part and

cannot be guaranteed. The mute function is not recom-

mended for the satellite mode.

4.1.9. DQPSK-Decoder

In case of NICAM-mode the phase samples are de-

coded according the DQPSK-Coding scheme. The out-

put of this block contains the original NICAM-bitstream,

which is available at the N-Bus interface.

4.1.10. NICAM-Decoder

Before any NICAM decoding can start, the MSP must

lock to the NICAM frame structure by searching and syn-

chronizing to the so-called Frame Alignment Words

(FAW).

To reconstruct the original digital sound samples the NI-

CAM-bitstream has to be descrambled, deinterleaved

and rescaled. Also bit error detection and correction

(concealment) is performed in this NICAM specific

block.

To facilitate the Central Control Unit CCU to switch the

TV-set to the actual sound mode, control information on

the NICAM mode and bit error rate are supplied by the

the NICAM-Decoder. It can be read out via the I2C-Bus.

4.2. Analog Section: SCART Switches and Standby

Mode

The analog input and output sections offer a wide range

of switching facilities, which are shown in Fig. 4â3.To de-

sign a TV set with 3 pairs of SCART-inputs and two pairs

of SCART-outputs, no external switching hardware is re-

quired.

The switches are controlled by the ACB bits defined in

the audio processing interface (see section 12. Pro-

gramming the Audio Processing Part).

If the MSP 3410 B is switched off by first pulling STAND-

BYQ low and then disconnecting the 5V but keeping the

8V power supply (âStandbyâ-mode), the switches S1,

ITT Semiconductors

S2 and S3 maintain their position and function. This fa-

cilitates the copying from selected SCART-inputs to

SCART-outputs in the TV-setâs standby mode.

SCART_IN

SC1_IN_L/R

MONO_IN

SC1_IN_L/R

SC3_IN_L/R

ACB[1:0]

to Audio Baseband

Processing (DFP_IN)

SCARTL/R

ACB[3:2]

from Audio Baseband

Processing (DFP)

SCARTL/R

ACB[5:4]

SCART_OUT

SC1_OUT_L/R

SC2_OUT_L/R

Fig. 4â3: SCART-Switching Facilities

Bold lines determine the default configuration

In case of power-on start or starting from standby, the IC

switches automatically to the default configuration,

shown in the figure above. This action takes place after

the first I2C transmission into the DFP part. By transmit-

ting the ACB register first, the individual default setting

mode of the TV set can be defined.

4.3. MSP 3410 B Audio Baseband Processing

By means of the DFP processor all audio baseband

functions are performed by digital signal processing

(DSP). The DSP functions are grouped into three pro-

cessing parts: Input preprocessing, channel selection

and channel postprocessing.

The input preprocessing is intended to prepare the vari-

ous signals of all input sources in order to form a stan-

dardized signal at the input to the channel selector. The

signals can be adjusted in volume, are processed with

the appropriate deemphasis and are dematrixed if nec-

essary.

Having prepared the signals that way, the channel selec-

tor makes it possible to distribute all possible source sig-

nals to the desired output channels.

The ability to route in an external coprocessor for special

effects like graphic equalizer, surround processing, and

sound field processing is of special importance. Routing

can be done with each input source and output channel

via the I2S inputs and outputs.

All input and output signals can be processed simulta-

neously with the exception that FM2 cannot be pro-

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