MSP4458 datasheet(10/85 Pages) MICRONAS

10 / 85 page

MSP 44x8G

PRELIMINARY DATA SHEET

Micronas

2.2.4. Automatic Sound Select

In the Automatic Sound Select mode, the dematrix

function is automatically selected based on the identifi-

cation information in the STATUS register. No I2C inter-

action is necessary when the broadcasted sound

mode changes (e.g. from mono to stereo).

The demodulator supports the identification check by

switching between mono compatible standards (stan-

dards that have the same FM mono carrier) automati-

cally and non-audible. If B/G-FM or B/G-NICAM is

selected, the MSP will switch between these stan-

dards. The same action is performed for the standards:

D/K1-FM, D/K2-FM, and D/K-NICAM. Switching is only

done in the absence of any stereo or bilingual identifi-

cation. If identification is found, the MSP keeps the

detected standard.

In case of high bit-error rates, the MSP 44x8G auto-

matically falls back from digital NICAM sound to ana-

log FM or AM mono.

Table 2–1 on page 11 summarizes all actions that take

place when Automatic Sound Select is switched on.

To provide more flexibility, the Automatic Sound Select

block prepares four different source channels of

demodulated sound (Fig. 2–2). By choosing one of the

four demodulator channels, the preferred sound mode

can be selected by means of the Source Select regis-

ters, independent for all MSP-outputs.

The following source channels of demodulated sound

are defined:

– “FM/AM” channel: Analog mono sound, stereo if

available. In case of NICAM, analog mono only

(FM or AM mono).

– “Stereo or A/B” channel: Analog or digital mono

sound, stereo if available. In case of bilingual broad-

cast, it contains both languages A (left) and B

(right).

– “Stereo or A” channel: Analog or digital mono

sound, stereo if available. In case of bilingual broad-

cast, it contains language A (on left and right).

– “Stereo or B” channel: Analog or digital mono

sound, stereo if available. In case of bilingual broad-

cast, it contains language B (on left and right).

Fig. 2–2 and Table 2–2 show the source channel

assignment of the demodulated signals in case of

Automatic Sound Select mode for all sound standards

(see Section 6.).

Note: The analog primary input channel contains the

signal of the mono FM/AM carrier or the L+R signal of

the MPX carrier. The secondary input channel con-

tains the signal of the second FM carrier, the L

−R sig-

nal of the MPX carrier, or the SAP signal.

Fig. 2–2: Source channel assignment of demodulated

signals in Automatic Sound Select Mode

2.2.5. Manual Mode

Fig. 2–3 shows the source channel assignment of

demodulated signals in case of manual mode. If man-

ual mode is required, more information can be found in

Section 6.7. “Demodulator Source Channels in Manual

Mode” on page 80.

Fig. 2–3: Source channel assignment of demodulated

signals in Manual Mode

Prescale

Automatic

Sound

Select

NICAM A

NICAM

FM/AM

Prescale

NICAM

FM/AM

Stereo or A/B

Stereo or A

Stereo or B

primary

channel

secondary

channel

LS Ch.

Matrix

SC2 Ch.

Matrix

Output-Ch.

Matrices must

be set once to

stereo

Prescale

primary

channel

secondary

channel

NICAM A

NICAM

FM/AM

Prescale

NICAM

FM/AM

(Stereo or A/B)

FM-Matrix

NICAM

LS Ch.

Matrix

SC2 Ch.

Matrix

Output-Ch.

Matrices

must be set

according

the standard

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