Video Block Test Conditions
Input signal
Video signal input
1DC voltage
Symbol
VIN1DC
Test point
28
LA76850
Input signal
L-100
Test method
Input signals to pin 28 and measure the voltage of
the pedestal.
Bus conditions
VIDEO SW:1
Video signal input
VIN1AC
1 AC voltage
28
Pin 28 recommended input level
Video overall gain
(Contrast max)
Contrast
adjustment
characteristics
(normal/max)
Contrast
adjustment
characteristics
(min/max)
Video frequency
Characteristics 1
(NTSC)
CONT127
CONT63
CONT0
BW1
L-50
17
L-50
17
L-50
17
L-CW
17
Video frequency
Characteristics 2
(PAL)
Chroma trap amount
PAL
BW2
CtraPP
L-CW
17
L-CW
17
Chroma trap amount
NTSC
CtraPN
L-CW
17
DC transmission
amount
ClampG1
L-0
17
L-100
Sharpness variable
range (PAL)
Sharp32T2
L-CW
17
(max)
Sharp63T2
L-CW
17
(min)
Sharp0T2
L-CW
17
Measure the output signal’s 50IRE amplitude
(CNTHB Vp-p) and calculate
CONT127 = 20log (CNTHB/0.357).
Measure the output signal’s 50IRE amplitude
(CNTCB Vp-p) and calculate
CONT63 = 20log (CNTCB/0.357).
CONTRAST:
1111111
CONTRAST:
0111111
Measure the output signal’s 50IRE amplitude
(CNTLB Vp-p) and calculate
CONT0 = 20log (CNTLB/0.357).
CONTRAST:
0000000
With the input signal’s continuous
Wave = 100kHz, measure the output signal’s
continuous wave amplitude (PEAKDC Vp-p).
With the input signal’s continuous
wave = 1.8MHz, measure the output signal’s
continuous wave amplitude (CW1.8 Vp-p).
Calculate BW1 = 20Log (CW1.8/PEAKDC).
With the input signal’s continuous
wave = 2.2MHz, measure the output signal’s
continuous wave amplitude (CW2.2 Vp-p).
Calculate BW2 = 20Log (CW2.2/PEAKDC).
With the input signal’s continuous
wave = 4.43MHz, measure the output signal’s
continuous wave amplitude (F0P Vp-p).
Calculate CtraP = 20Log (F0P/PEAKDC).
With the input signal’s continuous
wave = 3.58MHz, measure the output signal’s
continuous wave amplitude (F0N Vp-p).
Calculate CtraN = 20Log (F0N/PEAKDC).
Measure the output signal’s 0IRE DC level
(BRTPL V).
Measure the output signal’s 0IRE DC level
(DRVPH V) and 100IRE amplitude (DRVH Vp-p)
and calculate ClampG = 100 ×
(1+(DRVPH - BRTPL)/DRVH).
With the input signal’s continuous
wave = 2.7MHz, measure the output signal’s
continuous wave amplitude (F02S32 Vp-p).
Calculate Sharp32T3 = 20Log
(F02S32/PEAKDC).
With the input signal’s continuous
wave = 3MHz, measure the output signal’s
continuous wave amplitude (F02S63 Vp-p).
Calculate Sharp63T2 = 20Log
(F02S63/PEAKDC).
With the input signal’s continuous
wave = 3MHz, measure the output signal’s
continuous wave amplitude (F02S0 Vp-p).
Calculate Sharp0T2 = 20Log (F02S0/PEAKDC).
FILTER SYS: 0000
SHARPNESS:
000000
FILTER SYS: 0010
SHARPNESS:
000000
FILTER SYS: 010
Sharpness: 000000
FILTER SYS: 000
Sharpness: 000000
Brightness:
0000000
CONTRAST:
1111111
Brightness:
0000000
Contrast:
1111111
DCREST = 00
BLK.ST.DEF = 1
WPL = 0
Filter Sys:0010
Sharpness: 100000
Filter Sys:0010
Sharpness: 111111
Filter Sys:0010
Sharpness: 000000
Continued on next page.
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