Teledyne LeCroy QPHY-UWB - Manual (Page 28)

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QPHY-UWB-OM-E Rev C
COMMON PHASE ERROR (CPE) VERSUS TIME ANALYSIS
This view shows how the Common Phase Error of the carrier frequency of each band in the band group which is
used for the selected TFC varies over time, over the Header and the PSDU. This view does require UWB
processing to be done, so an entire packet (starting from the beginning, including at least 200ns of the inter
packet gap) must be seen. The vertical scale of each track is automatically set to use most of the height of the
grid, so it is important to look at the vertical scale-per-division in the trace descriptors, below the grids. In the
figure below two of the tracks are at 2 degrees/div and the third is at 5 degrees/div. These variations are small.
Although it may not be clearly visible, the track is flat from start to end of each symbol time over which CPE was
measured. A slanted line just connects measured values.
CPE of the first symbol of the PSDU is zero by definition. Because matching frequency eliminates the slope of
CPE across the PSDU, the CPE track will also end at zero; only the variations from symbol to symbol are shown.