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Using Oscilloscopes to Test
and Debug Analog HDTV Signals
Keysight Technologies, Inc. InfiniiVision 4000 X-Series
oscilloscopes with DSOX4VID option provide trigger and
display features ideal for debugging and characterizing
analog HDTV signals.
02 | Keysight | Using Oscilloscopes to Test and Debug Analog HDTV Signals - Application Brief
Today's consumer electronic designers must be proficient mixed Figure 3 shows the use of "Zone Trigger" on the 4000 X-Series
signal designers. Many devices have a combination of analog (audio, oscilloscope to isolate a particular video line. The video trigger is
video) and digital (HDMI, DisplayPort) interfaces. A composite video set to trigger on all lines. This line is not isolated by its line num-
input and/or output is still the lingua franca (working language) of ber, but by its waveform shape. With touch-drawn boxes that the
consumer electronics video devices. If a device has one, and most waveform "must intersect" or "must not intersect," it is easy to
do, it is an excellent way to quickly verify its correct operation, but trigger on only the desired lines. Note the use of an IRE graticule
you must have the right oscilloscope. and IRE cursor readout to measure the isolated line. InfiniiScan
Zone trigger is useful when you don't know the line number for
Figure 1 shows the display of a standard NTSC color bar signal a certain waveform shape. It is even more useful for capturing
triggered on all lines. The 4000 X-Series oscilloscope's 1 million intermittent errors when triggering on specific lines.
waveforms per second update rate is able to plot all lines, creating
an intensity graded image with details from the many different lines Another important aspect of high definition analog video is
that are readily apparent. Color bursts, sync pulses, color bars and minimizing noise. The hardware-accelerated averaging available
flat field are all visible. Lesser oscilloscopes may not keep up with in Keysight's InfiniiVision X-Series oscilloscopes can help track
the information available. down troublesome noise sources. Averaging removes all noise not
correlated to the trigger. Triggering on a noisy video signal and
Figure 2 shows the 4000 X-Series with DSOX4VID option triggering averaging will show a clean signal when noise is coming from an
on a 1080p/60 signal in the yellow channel. The green trace is a external source such as switching power supplies. Figure 4 shows
standard-definition composite NTSC signal that is being converted a flat field with thousands of averages applied. The clean signal
to the component HDTV signal in the yellow. Good triggering is tells us any noise is not correlated to the video line and, hence,
essential for debugging and characterizing such complicated tasks. not due to the video portion of the design.
Figure 3: Using InfiniiScan Zone trigger to isolate lines by content.
Figure 1: High-quality rendering of NTSC "Color Bars." Note IRE graticule and cursor measurements.
Figure 2: Triggering on 1080p/60 signals. Figure 4: Averaging this noisy `flat field' shows a clean signal. Therefore, we know
the noise is uncorrelated to the video and must look elsewhere for its source.
03 | Keysight | Using Oscilloscopes to Test and Debug Analog HDTV Signals - Application Brief
This document has shown just a few examples of typical video system measurements
that may be required. More advanced measurements may include mixed analog and For more information on Keysight
Technologies' products, applications or
digital measurements with the digital inputs of an InfiniiVision MSO model or I