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To analyze video waveforms
The TV sync separator in the oscilloscope has an internal clamp circuit. This
removes the need for external clamping when you are viewing unclamped
video signals. TV triggering requires two vertical divisions of display, either
channel 1 or channel 2 as the trigger source, and the selection of internal
trigger. Turning the trigger level knob in TV trigger does not change the
trigger level because the trigger level is automatically set to the sync pulse
tips.
For this exercise we connected the oscilloscope to the video output terminals
on a television. Then we set up the oscilloscope to view these parts of a TV
signal: the second vertical interval with delayed sweep windowed on the
vertical interval test signals (VITS) and the IRE displayed full screen.
1
Connect a TV signal to channel 1, then press
Autoscale
.
2
Press
Display
, then press the
Peak Det
softkey.
3
On HP 54645A, press
Slope/Glitch
, then press the
TV
softkey if
it is not selected, and
TV Menu
. In the TV menu, select the TV Mode to be
Field 2
.
4
On HP 54645D, press
Advanced
, then press the
TV
softkey if it is
not selected, and
TV Menu
. In the TV menu, select the TV Mode to be
Field 2
.
Polarity
Selects either positive or negative sync pulses.
Field 1
Triggers on the field 1 portion of the video signal.
Field 2
Triggers on the field 2 portion of the video signal.
Line
Triggers on all the TV line sync pulses.
HF Rej
Controls a 500-kHz, low-pass filter in the trigger path.
Making Measurements with HP 54645A/D Oscilloscopes
To analyze video waveforms
5-18
Summary of Contents for 54645A
Page 5: ...iv ...
Page 12: ...1 Getting Started ...
Page 25: ...1 14 ...
Page 26: ...2 Front Panel Overview ...
Page 60: ...3 Triggering HP 54645A D Oscilloscopes ...
Page 84: ...4 MegaZoom Concepts and Oscilloscope Operation ...
Page 142: ...5 Making Measurements with HP 54645A D Oscilloscopes ...
Page 176: ...6 Using Option 005 Enhanced TV Video Trigger HP 54645A ...
Page 189: ...6 14 ...
Page 190: ...7 Testing Adjusting and Troubleshooting ...
Page 242: ...8 Replacement Parts ...
Page 259: ...8 18 ...
Page 260: ...9 Performance Characteristics ...
Page 271: ...9 12 ...
Page 272: ...10 Messages ...