MSP4458 datasheet(78/85 Pages) MICRONAS

78 / 85 page

MSP 44x8G

PRELIMINARY DATA SHEET

Micronas

6.4.1. NICAM Mode Control/Additional Data Bits

NICAM operation mode control bits and A[2:0] of the

additional data bits.

Format:

Important: “S” = Bit[0] indicates correct NICAM-syn-

chronization (S = 1). If S = 0, the MSP 4418/4458G

has not yet synchronized correctly to frame and

sequence, or has lost synchronization. The remaining

read registers are therefore not valid. The MSP mutes

the NICAM output automatically and tries to synchro-

nize again as long as any NICAM standard is selected

by the STANDARD SELECT register.

The operation mode is coded by C4-C1 as shown in

Table 6–10.

Note: It is not necessary to read out and evaluate the

C_AD_BITS. All evaluation is performed in the MSP

and indicated in the STATUS register.

6.4.2. Additional Data Bits Register

Contains the remaining 8 of the 11 additional data bits.

The additional data bits are not yet defined by the

NICAM 728 system.

Format:

6.4.3. CIB Bits Register

CIB bits 1 and 2 (see NICAM 728 specifications).

Format:

6.4.4. NICAM Error Rate Register

Average error rate of the NICAM reception in a time

interval of 182 ms, which should be close to 0. The ini-

tial and maximum value of ERROR_RATE is 2047.

This value is also active if no NICAM-standard is

selected. Since the value is achieved by filtering, a cer-

tain transition time (approx. 0.5 sec) is unavoidable.

Acceptable audio may have error rates up to a value of

700dec. Individual evaluation of this value by the con-

troller and an appropriate threshold may define the fall-

back mode from NICAM to FM/AM-Mono in case of

poor NICAM reception.

The bit error rate per second (BER) can be calculated

by means of the following formula:

BER = ERROR_RATE * 12.3*10−6 /s

MSB

C_AD_BITS 00 23hex

LSB

...

7654

3210

Auto

_FM

...

A[2]

A[1]

A[0]

Table 6–10: NICAM operation modes as defined by

the EBU NICAM 728 specification

Operation Mode

Stereo sound (NICAMA/B),

independent mono sound (FM1)

Two independent mono signals

(NICAMA, FM1)

Three independent mono channels

(NICAMA, NICAMB, FM1)

Data transmission only; no audio

Stereo sound (NICAMA/B), FM1

carries same channel

One mono signal (NICAMA). FM1

carries same channel as NICAMA

Two independent mono channels

(NICAMA, NICAMB). FM1 carries

same channel as NICAMA

Data transmission only; no audio

Unimplemented sound coding

option (not yet defined by EBU

NICAM 728 specification)

AUTO_FM: monitor bit for the AUTO_FM Status:

0: NICAM source is NICAM

1: NICAM source is FM

MSB

ADD_BITS 00 38hex

LSB

54321

A[10]

A[9]

A[8]

A[7]

A[6]

A[5]

A[4]

A[3]

MSB

CIB_BITS 00 3Ehex

LSB

76543210

xxxxxx

CIB1

CIB2

ERROR_RATE

00 57hex

Error free

0000hex

maximum error rate

07FFhex

MSP4458 Datasheet(PDF) 78 Page - Micronas

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