Panasonic KX-B620 - Page 49

KX-B620 Series
KX-B520 Series
@
Explanation
of
the
block
diagram
of
LSI
‘MN86151
,
This
LS!
is
composed
of
four
blocks,
the
ADC
section,
ROM
section,
MUL
section
and
CTL
section.
Each
section’s
operation
is
as
follows:
@
ADC
(Analog
to
Digital
Converter)
section
The
pix
signal
(the
video
signal
from
the
analog
circuit)
is
compared
with
the
REF
signal
(+5V),
and
converted
to
digital
6
bit
signal.
@
ROM
(Mapping
Read
Only
Memory)
section
The
distortion
coefficient
data
is
mapped
to
the
external
RAM
by
this
mapping
ROM.
The
Output
of
ADC
section
is
used
for
the
address
of
this
ROM.
@
MUL
(Multiplier)
section
This
section
is
a
multiplier
of
6X6
bit.
@
CTL
(Control)
section
The
functions
of
this
section
are
control
of
shading
correcting,
control
of
ADC,
and
interface
to
external
RAM.
@
Operation
of
LS!
(Step
1)
Blank
(white
area)
reading
The
video
signal
of
the
blank
(white
area)
is
inputted
in
VIN
pin,
and
“L”
pulse
is
fed
in
SHST
pin,
which
causes
this
LSI.
to
memory
the
distortion
coefficient
6
bit
data
for
each
pixel
to
the
external
RAM.
SHST
Sf
ee
U
Fig. 22
The
coefficient
data
is
induced
from
the
following
formula.
Dx:
distortion
coefficient
data
(¢
—6310)
Dw:
base
data
of
white
(¢
—6310)
Dw=!Int. [
(VwW/75)
X64+0.5
J
Vw:
video
signal
voltage
of
white
area
(0—5V)
a)
50%
compensative
Mode
(not
used)
—
Dx=Int.
(2,048/Dw)
SEs
(if
Vw
is
below
2.5V,
Dx
is
fixed
to
63.)
b)
75%
compensative
Mode
Dk=Int.
(1,024/Dw)
(if
Vw
is
below
1.25V,
Dx
is
fixed
to
63.)
(Step
2)
Compensation
“UW”
level
of
SHST
is
inputted
and
video
signal
of
the
document
area
on
the
screen
is
inputted
from
VIN
pin.
This
LSI
calculates
the
compensated
output
data
of
each
pixel
from
the
video
signal
and
the
distortion
coefficient
data
of
the
external
RAM.
The
data
is
induced
from
the
following
formula.
Ds:
compensated
output
data
(¢
—3110)
Dk:
distortion
coefficient
data
(¢
—6310)
Dp:
document
signal
data
(¢
—6310)
Dp=Int.
[
(Vp/5)
X64+0.5
J
Vp:
video
signal
voltage
document
area
(0—-5V)
a)
50%
compensative
mode
(not
used)
Db=Int.
(Dp
x
Dk
764)
b)
75%
compensative
mode
Db=!Int.
(Dp
X
Dk
32)
lf
Db2=32,
then
Da=3110
and
OVF=
‘H’
If
Db<32,
then
Dp=Db
and
OVF=
‘LU’