Tektronix 1740A/1750A - Manual (Page 90)

Basic Measurements
1740A/1750A Series Waveform/Vector Monitor User Manual
4-9
Making Vector Measurements
Chroma Bandwidth
The horizontal and vertical axes of the vector graticule
contain markings for checking chroma bandwidth. A subcar-
rier frequency sine wave (whose amplitude places it on the
outer compass rose) is used as a reference. When the fre-
quency is changed, the diameter of the circle should reduce.
At a point equal to 70% of full amplitude (--3 dB), there are
gaps in the horizontal and vertical axes. This calibration aid
makes it possible to check the --3 dB points of the demodula-
tor output amplifiers.
Differential Phase and Gain
Differential gain (dG) and differential phase (d
∅) measure-
ments use the graticule markings located at the outer edge of
the B--Y or U axis. See Figure 4-5.
10 o
2° dφ
dφ
Figure 4-5. Differential Gain and Phase Measurements.
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