Atec Tektronix-VM700T - Manual (Page 14)

Blanking Variation: Measured
as the peak-to-peak variation
of the blanking level within
every third line of a field.
Frequency Response Measurements
(FCC Multiburst or NTC-7
Combination VITS)
Multiburst Flag Amplitude:
Measured from back porch
blanking to the center point of
the flag top.
Multiburst Amplitude:
Measured as the peak-to-peak
amplitude of each of the
multiburst packets. Six results
reported.
Waveform Distortion Measurements
(FCC or NTC-7 Composite VITS)
Line Time Distortion:
Measured as the peak-to-peak
amplitude change of the bar
top, excluding the first
microsecond and the last
microsecond.
Pulse-to-Bar Ratio: Measured
as the peak amplitude of the
2T pulse, expressed as a
percent of the bar amplitude.
Short-Time Waveform
Distortion: Measured as a
weighted function of time, the
result is the peak deviation
from flatness within 1
microsecond of the center of a
bar transition. ANSI/IEEE
Std.-511-1979, Section 4.4,
Appendix B.
Chrominance Non-linear Gain
Distortion: Measured as the
peak-to-peak amplitude of the
first (nominally 20 IRE) and
last (nominally 80 IRE)
chrominance packets in the
3-level chrominance signal,
referenced to the peak-to-peak
amplitude of the middle
packet (nominally 40 IRE).
Chrominance Non-linear
Phase Distortion: Measured
as the difference between the
largest and the smallest
deviation in phase among the
3-level chrominance test signal
subcarrier packets.
Chrominance to Luminance
Intermodulation: Measured
using the 3-level chrominance
test signal. Result is the maxi-
mum amplitude departure of a
filtered part of the luminance
pedestal from a part of the
pedestal upon which no sub-
carrier has been superimposed.
2T Pulse K-factor: Measured
as the greatest weighted ampli-
tude of a positive-going or
negative-going echo-term
half-wave which is within one
microsecond before the 2T
pulse leading edge half-
amplitude point or within
one microsecond after the 2T
pulse trailing edge half-ampli-
tude point. Result expressed as
a K-factor which is the ratio of
the weighted amplitude of the
echo-term half-wave to the
sampled amplitude of the
2T pulse.
VIRS Measurements
VIRS Setup (Reference Black):
Measured from the blanking
level included in the test
signal to setup level.
VIRS Chrominance Reference
Amplitude: Measured as the
amplitude of the VIRS chromi-
nance packet, expressed as a
percent of burst (or percent of
bar if no burst).
VIRS Chrominance Phase
Relative to Burst: Measured as
the difference between the
VIRS chrominance packet
phase and color burst phase.
VIRS Luminance Reference:
Measured from the blanking
level included in the test
signal to luminance reference
level (nominally 50 IRE).
Signal-to-Noise Ratio Measurements
Unweighted SNR: Measured as
the ratio of bar amplitude to
the unweighted rms amplitude
of the noise on a quiet line.
Luminance Weighted SNR:
Measured as the ratio of bar
amplitude to the luminance
weighted rms amplitude of the
noise on a quiet line.
Periodic SNR: Measured as
the ratio of bar amplitude to
the peak-to-peak value of the
periodic noise.
Out-of-Service Measurements
Long Time Distortion: Measured
as the peak overshoot and
settling time in a flat field test
signal switched from 10% to
90% APL in less than 10 µsec.
Field Time Distortion:
Measured as the peak-to-peak
amplitude change of the 100
IRE field squarewave top.
The first and last 250 µsec
are excluded. Expressed as
a percent of the field
squarewave amplitude.
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