July 1993

10

Philips Semiconductors

Product specification

Terrestrial Digital Sound Decoder (TDSD2)

SAA7282

CFC

Signals a change of configuration at the 16-frame

status register.

E7 to E0

This is an error count byte which counts the number of

error flags in a 128 ms period. The register is updated

every 128 ms.

AD10 to AD0

These are the additional data bits from the transmission

and are updated every 1 ms.This provides a data capacity

of 11 kbit/s.

SAD

SAD is the 'status additional data' bit. This is set to logic 1

registers. It is automatically reset to logic 0 when

AD_BYTE_1 is read by the bus master.

OVW

OVW is the overwrite indicator for the additional data.

This bit is set when the transmission overwrites additional

data bits which have not been read by the bus master.

This bit is automatically reset to logic 0 when AD_BYTE_1

is read by the bus master.

CI1 to CI2

These represent the CI bits which are extracted by a

majority logic process from the parity checks of the last ten

samples in a frame (samples 55 to 64). CI1 will be

conveyed by the parity grouping of samples 55 to 59 and

CI2 will be conducted by the parity grouping of samples 60

to 64. Both parity groups will be even for UK transmissions

such that CI2 = logic 0 and CI1 = logic 0. The

transmissions of countries following the specification

issued by the EBU (Document SPB424;

“Digital sound

transmissions in terrestrial television”) will allow odd or

even parity groups, thus providing an additional 2 kbit/s

data capacity.

Table 6

Indicator bits functional truth table.

Note

1. Holds last value before synchronization loss or stereo (S/M = logic 1; D/S = logic 0) if synchronization not achieved

since power-on reset.

TRANSMISSION

C1

C2

C3

S/M

D/S

VDSP

OS

Stereo

0

0

0

1

0

1

1

M1

+ M2

0

1

0

0

1

1

1

M1

+ data

1

0

0

0

0

1

1

Transparent data

1

1

0

0

0

0

1

Any currently undefined combination of C1, C2, C3

0

0

0

1

Decoder unsynchronized (OS = logic 0)

note 1

note 1

0

0