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Making waveform measurements – Tektronix 1760 User Manual

Page 105

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Basic Measurements

1760 Series Component Waveform/Vector Monitor User Manual

4-5

Making Waveform Measurements

Horizontal Sync Amplitude

The vertical scale at sync tip (40 IRE NTSC or --0.3 V PAL)
provides

±2 and ±4 IRE (± 2 and ±4 mV) for measuring sync

amplitude. Align the blanking level of a centered two

-

line

waveform display on the graticule baseline to place the sync
pulse directly over this structure. Measure sync amplitude
directly from the graticule, or use the voltage cursors.

Peak White

With the blanking signal level on the graticule baseline, the
amplitude of the 100% white reference of a color bar should
be on the 100 IRE (1 V) graticule line. With a

2 LINE

sweep

rate, use the

HORIZ POS

control to place the white reference

directly over the amplitude scale at graticule center. The
vertical markings there correspond to 2 IRE/division (10 mV/
division for PAL). Measure peak white directly from the
graticule or use the voltage cursors.

K-Factor Measurements

The boxed area in the upper left corner of the graticule is
scaled for 2% and 4% K--Factor ratings for precise tilt mea-
surements. This structure is designed to work with an 8

µs

half-amplitude duration (HAD) bar. The bar tilt measure-
ment structure can also be used to measure pulse-to-bar ratio.
Calibrated

X5 GAIN

can be used while making these measure-

ments; it increases resolution to 0.4% and 0.8%.

To use the NTSC vertical scale to make line-time distortion
and pulse-to-bar ratio measurements, position the signal
blanking level to the graticule baseline. Next, position the
center of the composite test signal bar to the center of the 2T
bar measurement box and check to see if insertion gain is
unity. If it is not, adjust the

VARIABLE GAIN

(enabled from the

GAIN MENU

) for exactly 100 IRE (700 mV PAL) of signal

amplitude from baseline to the middle of the white bar.