CXA3106Q
CLK Jitter Evaluation Method
The regenerated CLK is obtained by applying Hsync to the CXA3106Q. Apply this CLK to a digital
oscilloscope and observe the CLK waveform using Hsync as the trigger.
triger
Digital
Oscillo-
scope
Hsync
CLK
Pulse
Generator
CXA3106Q
ch1
H
Back
Active
Video
Front
Porch
Sync Porch
Computer signal
Hsync
15 to 25% of Tsync
Tsync = 1/fsync
CLK
Enlarged
Enlarged
Enlarged
Enlarged
Trigger
CLK
Tjp-p
The CLK jitter is measured at peak to peak in the long-term write mode of the digital oscilloscope as shown in
the figure. The CLK jitter size varies according to the difference in the relative position with respect to Hsync.
Therefore, when the observation point is changed, the CLK jitter at that point is observed.
The figure below shows an typical example of the CLK jitter for the CXA3106Q.
The CLK jitter increases slightly at the rising edge of Hsync (in the case of positive polarity), and then settles
down thereafter. However, this is not a problem as the active pixels start after about 20% of the H cycle has
passed from the rising edge of Hsync.
0
1/4 · Tsync
2/4 · Tsync
3/4 · Tsync
Tsync
Observation points
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SONY [ SONY CORPORATION ]
