Reading The VLM-40 – 9
A
VERAGE
L
UMINANCE
...
P
EAK
L
UMINANCE
...
VLM-40 NTSC T
ECHNICAL
I
NSTRUCTION
M
ANUAL
OPERATION
Average luminance is displayed as a continuously-lit green bar on
the VLM-40. Each LED equals 4 IRE units. Average luminance is
equal to the largest valued LED on the right end of the bar, as
shown in Fig. 9. The indicated value corresponds to the average
(calculated) luminance level on a waveform monitor.
Peak luminance below 100 IRE is displayed as a single lit green
LED to the right of the continuously-lit bar on the VLM-40.
Values above 100 IRE are red. The indicated value corresponds
to the value of peak luminance on a waveform monitor, as
shown in Fig. 10.
NOTE: The VLM-40 is very sensitive to measuring noise in the
luminance signal and will respond to short impulses that may be
undetected on a standard waveform monitor.
COMPOSITE VIDEO LUMINANCE METER
MODEL VLM-40
-48
-40
0
20
40
60
80
100
120
© 1990
SYNC
LUMINANCE
IRE UNITS
-32
SYNC
SETUP
IRE Units
100
80
60
40
20
-20
-40
0
setup = 7.5
average
luminance =
area under curve
Fig. 9. The average luminance level on the VLM-40 corresponds to the
average (calculated) luminance level on a waveform monitor.
COMPOSITE VIDEO LUMINANCE METER
MODEL VLM-40
-48
-40
0
20
40
60
80
100
120
© 1990
SYNC
LUMINANCE
IRE UNITS
-32
SYNC
SETUP
IRE Units
100
80
60
40
20
-20
-40
0
setup = 7.5
Fig. 10. The peak luminance level on the VLM-40 corresponds to the
peak luminance level on a waveform monitor.
