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Fig. 5, above left
Two-channel A/D video converter
Fig. 6, above centre
Two-channel ADPCM video encoder
Fig. 8, above right
Audio decoder for four channels
ent sample with 32-level resolution (corresponding
to five bits). The quantizer
has two modes and is switched between
them on the basis of information from
earlier values on the same line and also
values from the preceding line (two-dimensional
prediction).
The encoder is adaptive, which means
that it switches between the two quantizing
ranges, fine and coarse, depending
on the picture content. Control ol
the adaptivity is optimized for maximal
subjective quality, i.e. is determined by
how the eye perceives the picture.
Fig. 7a
Block diagram of PCM audio encoder
Analog
audio signal
14 bits
Linear PCM
Serial
audio dala
In 1 (H)O-j—
14
-f-
15
I 7 MSB
Generation
of
parity bit
PISO
-I*- Out
i 7 MSB
Generation
of
parity bit
In 2(V) o -U^
X)
14
Data clock
Sampling clocks
f = 960 kHz
f« = 32 kHz
Fig. 7b
Block diagram of PCM audio decoder
Serial
audio data
n O I • SIPO
Data clock
11 /ISB
7ti rfSB
15
Parity
check
Parity
check
t
15
t m
1
1
Buffer
Buffer
14 bits
Linear PCM
1
k
D /
A
/
Sampling clocks
I
/ H
i
Sin x
X
Sin x
X
oo
oo
Analog
audio signal
H
|
1
I 1
i
j
I
1
|
i — ^
I
1
„ Out 11
Out 2 •
f = 960 kHz
t = 32 kHz