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Measurements
4–6
1780R-Series Operator’s Manual
3. Use the vectorscope variable gain control to set the amplitude of
the chroma to be measured to the edge of the compass rose.
4. Use the large knob to set the phase of the chroma to be measured
to the nine o’clock position. See Figure 4–3.
5. Use the Waveform Vertical Position control to place the
beginning of the trace on a reference graticule mark.
6. Differential phase is that amount of signal that lies above or
below the reference graticule mark. Read the amount directly off
the graticule scale (waveform CRT); 1 major division = 1_
(10 IRE NTSC or 100 mV PAL).
Double-Trace DIFF PHASE Measurement Procedure
1. Apply a staircase signal or a ramp signal with subcarrier to the
1780R-Series.
2. Touch <DOUBLE>.
3. Use the vectorscope variable gain control to set the amplitude of
the chroma to be measured as desired, usually to the compass
rose. In Double DIFF PHASE mode only, this setting may be
altered to improve vertical resolution without affecting the
accuracy of the readout.
4. Use the large knob to bring the left ends of the two traces
(waveform CRT) together.
5. Push the REFERENCE SET front-panel button. Phase readout
should be 0.00_.
6. Locate the point of largest deviation between the two traces, and
use the large knob to bring the two traces together at that point.
7. Phase readout now gives the total amount of differential phase.
To measure the differential phase of each step in the signal,
repeat the process, bringing each individual step together.
Using Line Select in DIFF PHASE
1. Push the front-panel LINE SELECT button to enable Line Select
mode. Both the waveform monitor and vectorscope will be in
Line Select, and display the same line.
Measurements
4–6
1780R-Series Operator’s Manual
3. Use the vectorscope variable gain control to set the amplitude of
the chroma to be measured to the edge of the compass rose.
4. Use the large knob to set the phase of the chroma to be measured
to the nine o’clock position. See Figure 4–3.
5. Use the Waveform Vertical Position control to place the
beginning of the trace on a reference graticule mark.
6. Differential phase is that amount of signal that lies above or
below the reference graticule mark. Read the amount directly off
the graticule scale (waveform CRT); 1 major division = 1_
(10 IRE NTSC or 100 mV PAL).
Double-Trace DIFF PHASE Measurement Procedure
1. Apply a staircase signal or a ramp signal with subcarrier to the
1780R-Series.
2. Touch <DOUBLE>.
3. Use the vectorscope variable gain control to set the amplitude of
the chroma to be measured as desired, usually to the compass
rose. In Double DIFF PHASE mode only, this setting may be
altered to improve vertical resolution without affecting the
accuracy of the readout.
4. Use the large knob to bring the left ends of the two traces
(waveform CRT) together.
5. Push the REFERENCE SET front-panel button. Phase readout
should be 0.00_.
6. Locate the point of largest deviation between the two traces, and
use the large knob to bring the two traces together at that point.
7. Phase readout now gives the total amount of differential phase.
To measure the differential phase of each step in the signal,
repeat the process, bringing each individual step together.
Using Line Select in DIFF PHASE
1. Push the front-panel LINE SELECT button to enable Line Select
mode. Both the waveform monitor and vectorscope will be in
Line Select, and display the same line.