MSP3410B datasheet(9/68 Pages) MICRONAS

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PRELIMINARY DATA SHEET

MSP 3410 B

ITT Semiconductors

4. Architecture of the MSP 3410 B

Fig. 4–1 shows a simplified block diagram of the IC. Its

architecture is split into three functional blocks:

1. demodulator and decoder section

2. digital signal processing (DSP) section performing

audio baseband processing

3. analog section containing two A/D-converters,

6 D/A-converters, and channel selection

4.1. Demodulator Block

4.1.1. Analog Sound IF – Input Section

The input pins ANA_IN1+, ANA_IN2+ and ANA_IN– of-

fer the possibility to connect two different sound IF

sources to the MSP 3410 B. By means of bit [8] of

AD_CV (see Table 11–2) either terrestrial or satellite

sound IF signals can be selected. The analog-to-digital

conversion of the preselected sound IF signal is done by

a flash-converter, whose output can be used to control

an analog automatic gain circuit (AGC), providing opti-

mum level for a wide range of input levels. It is possible

to switch between automatic gain control and a fixed

(setable) input gain. In the optimum case, the input

range of the AD converter is completely covered by the

sound if source. Some combinations of SAW filters and

sound IF mixer ICs however show large picture compo-

nents on their outputs. In this case filtering is recom-

mended. It was found, that the high pass filters formed

by the coupling capacitors at pins ANA_IN1+ and

ANA_IN2+ (as shown in the application diagram) are

sufficient in most cases.

4.1.2. Quadrature Mixers

The digital input coming from the integrated A/D conver-

ter may contain audio information at a frequency range

of theoretically 0 to 9 MHz corresponding to the selected

standards. By means of two programmable quadrature

mixers two different audio sources, for example NICAM

and FM-mono, may be shifted into baseband position.

In the following, the two main channels are provided to

process either:

– NICAM (channel 1) and FM mono (channel 2) simulta-

neously or, alternatively,

– FM2 (channel 1) and FM1 (channel 2).

Two independent digital oscillators are provided to gen-

erate two pairs of sin/cos-functions. Two programmable

increments, to be divided up into Low- and High Part,

determine frequency of the oscillator, which corre-

sponds to the frequency of the desired audio carrier. In

section 11.1., format and values of the increments are

listed.

Demodulator

IDENT

DFP

Sound IF

Loudspeaker

DACM_L

DACA_L

SC1_OUT_L

Headphone

Mono

SCART1

SCART2

D/A

SCART3

SCART 1

SCART 2

FM1

FM2

NICAM A

NICAM B

SCART_L

SCART_R

SCART_L

SCART_R

I2SL/R I2SL/R

S1...4

HEADPHONE L

HEADPHONE R

LOUD-

SPEAKER R

LOUD-

SPEAKER L

IDENT

A/D

DACM_R

DACA_R

SC1_OUT_R

SC2_OUT_L

SC2_OUT_R

ANA_IN1+

ANA_IN2+

MONO_IN

SC1_IN_L

SC1_IN_R

SC2_IN_L

SC2_IN_R

SC3_IN_L

SC3_IN_R

S_CL

S_DA_IN

S_DA_OUT

S_ID

I2S_CL

I2S_DA_IN

I2S_DA_OUT

I2S_WS

SBUS Interface

I2S Interface

Fig. 4–1: Architecture of the MSP 3410 B

SCART Switching Facilities

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