Ensemble Designs 5400 Dual Sync Generator and Test Signal Generator with HD Tri-Level Sync User Manual
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Ramp Test Patterns
Ramp test patterns are very useful for evaluating linearity, missing bits, timing errors,
and dynamic range.
If there is a problem with linearity, the ramp will not be a straight line. If there is a
missing bit, the ramp will be broken up into smaller ramps. If there is a timing error,
vertical lines which are often noisy can appear. If there is a dynamic range problem,
clipping will occur at the top or the bottom of the ramp.
Video Ramp
The video ramp test pattern goes from black to peak white across the line (040h to
3ACh for luminance and 040h to 3C0h for chrominance). Because there are more
samples in an active digital line than levels of gray and chroma, there are some
repeated steps across the line. This pattern is used especially for linearity, missing
bit levels, and timing errors.
Data Ramp
The data ramp test pattern goes from minimum to maximum legal digital values
(004h to 3FBh) in one step per sample increments. The ramp therefore restarts
part of the way across the line. Because it uses the entire dynamic range, it is
especially useful to check for clipping in each of the component channels, Y, Cb,
and Cr.
Shallow Ramp
The shallow ramp test pattern goes from 1E2h to 21Dh passing through the
critical 1FFh/200h point where all 10 bits change state. This pattern can be
examined closely using a waveform monitor to evaluate DAC/ADC step size unifor-
mity and can be used to detect timing errors.
5 Step Ramp
The five step ramp test pattern has five steps:
Step 0: 040h and 040
Step 1: 0F0h and 0F4h
Step 2: 1A0h and 1A8h
Step 3: 252h and 25Ch
Step 4: 300h and 310h
Step 5: 3B0h and 3C4h
This pattern is used for aligning display systems such as a projector.
DAC Test
The DAC Test Pattern is alternating vertical bands of 1FFh and 200h across the
line.
At the transitions between 1FFh and 200h, all 10 bits of a digital signal change,
which can be problematic in DACs. Normally this step should not be visible on a
monitor, but if there is a problem, then vertical stripes will appear.
5400-A4
Model 5400 Dual Sync Gen/Test Signal Generator