User manual

Reference: Making Measurements
WFM 90 & WFM 91 User Manual
3–11
Making Waveform Measurements
Standard Measurements
Standard amplitude and timing measurements of the signal are made
by positioning the waveform on the graticule. The magnification
controls aid in measuring small portions of the waveform.
Peak White
With the signal blanking level on the graticule baseline, the
amplitude of the 100% white reference of a color bar should be on
the 100 IRE (1.0 V PAL) graticule line. The Amplitude Alarm mode
highlights any portion of the signal which exceeds the 100 IRE
(1.0 V PAL) graticule line.
DC Restorer
Use the
SLOW setting for the DC restorer to measure hum or other
low-frequency distortions. The
FAST setting removes hum from the
display so it will not interfere with other measurements. The back
porch portion of the input signal is used as the clamping point.
NOTE. DC Restorer use with VCRs
When using the shuttle mode on VCRs, set the instrument DC restorer
speed to slow to prevent the loss of signal sychronization.
Vector Graticule
The Vector display mode permits measurements of hue in terms of
the relative phase of the chrominance signal with respect to the color
burst. Relative amplitude of chrominance to burst is expressed in
terms of the displacement from center (radial dimension of
amplitude). The two versions of the vector graticule are illustrated in
Figure 3–3 and Figure 3–4:
 NTSC composite vector graticule (WFM 90 only)
 PAL (CCIR) composite vector graticule (WFM 91 only)