-7-
F7YLV
the fields and other one is simply reading out field data twice with double scanning frequency. In
the SAA4977H, the converted 8bit Y-signal is added sharpness processing and the converted 8bit
U/V-signals are added the CTI processing. The processed signals which become 10 bit digital
signals are demodulated to analogue Y/U/V signals by the10 bit D/A converter with 32MHz clock
rate (the double of input A/D sampling).
The Y/U/V signals up-converted to 100Hz are eliminated the clock components at external 12MHz
LPF, and output from the scan converter circuit after adjusting the gain amplitude for sharpness
IC, TDA9178, at the next stage. Also 100Hz H-sync and V-sync signals are supplied to the
deflection circuit.
The clock used for system control is line lock clock. The H/V signals which is synchronised with
Y/U/V signals are sent to the scan converter for timing control. The PLL/VCO circuits generate a
system clock 32MHz by referring to its 15.7kHz H-signal. The PLL, MC74HC4046AF, phase
compares the H-signal getting waveform-shaped at TC7S32F and the signal getting divided
32MHz clock by 1024 and controls VCO circuit at the next stage to synchronise the phase. After
waveform-shaping at TC7SU04F and TC7SH00F, its clock signal are supplied to each ICs as the
32MHz system clock.
The making of display information with 100Hz scan conversion is performed by the following
format.
1) Digital scan
odd field
even field
odd field
even field
odd field
Signal
A
B
C
D
E
100Hz scan field *
o
e
o
e
o
e
o
e
o
e
Display field
A+b
a+B
B+c
b+C
C+d
c+D
D+e
d+E
E+f
e+F
* e = even, o = odd field
The display field picture information on the digital scan is made by analysing the 2 fields previous
data stored in the field memory. The digital scan analyses the picture information on the same
peripheral area of the pixel between the fields and detects the motion vector, and creates a new
field picture information according to its motion.
The small and capital letter show which field data is emphasised when making the field data. The
capital letter shows emphasised field data.
50Hz
100Hz
A
B
C
A
A
B
B
C
A' = A, B'= B
(a) Normal Scan
(b) Normal Double Scan
100Hz
A+b
a+B
B+c
b+C
c+D
(C) Digital Double Scan
Fig.-8
Содержание CE32WH3-F
Страница 27: ... 27 F7YLV IC7206 IC7207 SAA4955TJ Field Memory IC7205 SAA4991WP MELZONIC Digital Scan Conversion ...
Страница 35: ... 35 F7YLV 17 20 21 5 19 2 16 15 18 4 11 ...
Страница 68: ...MAIN BOARD CIRCUIT SIDE MAIN BOARD COMPONENT SIDE ...
Страница 69: ...POWER DEFLECTION BOARD CIRCUIT SIDE POWER DEFLECTION BOARD COMPONENT SIDE Part No 1AA6P2P0955 F7YLV SHEET 5 9 ...
Страница 79: ......