Testing Conditions - Hitachi 17LD4200 Service Manual

2.7 TESTING CONDITIONS

Pattern Checking
Circle Overall Linearity , Geometry
Framing.
Reflections aspect ratio format
Center Cross Pin-cushion correction
Deflection Linearity
Crosshatch Static convergence
Dynamic convergence
Pin-cushion correction
Multi burst Video Bandwidth
Amplitude response/resolution
Color Bars Overall color performance
Burst keying
Sub-carrier regenerator
Matrix circuit
RGB amplifiers
Delay color versus b/w signal
Saturation check
562.5KHz interference check
VCR White level
Amplitude response,
resolution of VCR and other
video recorders
Linearity of chroma amplitude
Sensitivity color amplitude
Color AGC
Ratio chroma / luminance
Writing current
Recording performance
Slow/quick-motion
Still picture
On a black background is suited for checking the
overall linearity and geometry
The white circle changes automatically to black
when used with the white pattern and is useful for
checking reflection.
It is applied to check the deflection linearity
And for pin-cushion correction
Full screen definition pattern of
8vert. Bars 0.8MHz to 4.8MHz.
Contains eight full screen vertical bars of definition
lines in the frequency ranges 0.8,
1.8,2.8,3.0,3.2,3.4,3.8,and 4.8 MHz This checks the
bandwidth of the video or luminance amplifier in
black and white or color TV as well as the
resolution of monitor and video recorders
The vertical bars are white, yellow, cyan, green,
magenta, red, blue, and black. The luminance
content depends on the TV system selected and is
automatically correct after the user makes the
selection. The color bar pattern in fact provides
sufficient information for a good overall check on
color performance. This includes the checks on
burst keying, sub-carrier regeneration, RGB
amplifiers, the delay color versus B/W signal and
saturation check
Check the bandwidth , linearity , sensitivity , and
AGC of the chroma amplifiers in color video
recorders . This combined test pattern is divided into
the following four horizontal segments:
-Horizontal 100% white bar covering 1/16 field for
exact level adjustment
-Eight bars of resolution of which
2.8-3.0-3.2-3.4MHz are used to align the high-pass
filter for a maximum resolution in VCR bandwidth
-The next part of the pattern contains eight steps of
decreasing linear levels of saturation of 100%to 0%
to check the chroma amplifier linearity and color
AGC circuitry. For example, if the chroma writing
current is too high, color will be visible in the last
bar where no color should be seen normally
-The bottom section consists of black horizontal bar
with a moving white field to check moving pictures
on video recorders
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