MSP3400CPP Просмотр технического описания (PDF) - Micronas

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MSP3400CPP

Multistandard Sound Processor

Micronas 

PRELIMINARY DATA SHEET

MSP 3400C

4.2. Analog Section and SCART Switching Facilities

The analog input and output sections offer a wide range

of switching facilities, which are shown in Fig. 4–3. To

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

pairs of SCART-outputs, no external switching hardware

is required.

The switches are controlled by the ACB bits defined in

the audio processing interface (see section 7. Program-

ming the Audio Processing Part).

If the MSP 3400C is switched off by first pulling STAND-

BYQ low, and then disconnecting the 5 V, but keeping

the 8 V power supply (‘Standby’-mode), the switches

S1, S2, and S3 maintain their position and function. This

facilitates the copying from selected SCART-inputs to

SCART-outputs in the TV-sets standby mode.

SCART_IN

SC1_IN_L/R

2

MONO

2

SC2_IN_L/R

2

SC3_IN_L/R

2

from Audio Baseband

Processing (DFP)

SCARTL/R

D

2A

ACB[1:0]

00

to Audio Baseband

Processing (DFP)

01

A

D2

10

SCARTL/R

11 S1

ACB[3:2]

2

00

2

01

2

10

2

11 S2

ACB[5:4]

SCART_OUT

2

SC1_OUT_L/R

2

00

2

01

2

10 S3

2

SC2_OUT_L/R

Fig. 4–3: 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 Fig. 4–3. This takes place after the first I2C

transmission into the DFP part. By transmitting the ACB

register first, the default setting mode can be changed.

4.3. MSP 3400C 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 surround and sound field processing is of

special importance. Routing can be done with each input

source and output channel via the I2S inputs and out-

puts.

All input and output signals can be processed simulta-

neously. Note that the NICAM input signals are only

available in the MSP 3410 version. While processing the

adaptive deemphasis, no dual carrier stereo (German or

Korean) is possible. Identification values are not valid ei-

ther.

4.3.1. Dual Carrier FM Stereo/Bilingual Detection

In the German and Korean TV standard, audio informa-

tion can be transmitted in three modes: mono, stereo, or

bilingual. To obtain information about the current audio

operation mode, the MSP 3400C detects the so-called

identification signal. Information is supplied via the Ste-

reo Detection Register to an external CCU.

IDENT

AM

Demodu-

lation

Stereo

Detection

Filter

Bilingual

Detection

Filter

Level

Detect

–

Level

Detect

Fig. 4–4: Stereo/bilingual detection

Stereo

Detection

Register

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