Teledyne Lecroy WaveSurfer 3000, Руководство оператора, Страница: 46 / 97

WaveSurfer 3000 Oscilloscopes
Persistence Overview
The Persistence feature retains waveform traces on the display for a set amount of time before allowing them to
gradually "decay," similar to the display of old phosphor screen oscilloscopes. Use Persistence to accumulate on-
screen points from many acquisitions to see your signal change over time. The persistence modes show the most
frequent signal path in three-dimensional intensities of the same color (Analog), or graded in a spectrum of colors
(Color). You can show persistence for any channel, math function, or memory.
Access the Persistence dialog by choosing Display > Persistence Setup . Check Persistence On to shown persistence,
then select the mode, saturation level, persistence time, and last trace display.
Persistence Mode
The Persistence display is generated by repeated sampling of the amplitudes of events over time, and the accumulation
of the sampled data into display maps. These maps create an analog-style display. Statistical integrity is preserved
because the duration (decay) is proportional to the persistence population for each amplitude or time combination in the
data.
In Analog Mode , as a persistence data map develops, different intensities of that color are assigned to the range
between a minimum and a maximum population. The maximum population automatically gets the highest intensity, the
minimum population gets the lowest intensity, and intermediate populations get intensities in between these extremes.
The information in the lower populations (for example, down at the noise level) could be of greater interest to you than
the rest. The Analog persistence view highlights the distribution of data so that you can examine it in detail.
Color Mode persistence works on the same principle as Analog persistence, but instead uses the entire color spectrum
to map signal intensity: violet for minimum population, red for maximum population. In this mode, all traces use all
colors, which is helpful for comparing amplitudes by seeking like colors among the traces.
Saturation Level
Besides the different modes, you can select a saturation level as a percentage of the maximum population. All
populations above the saturation population are then assigned the highest color intensity: that is, they are saturated. At
the same time, all populations below the saturation level are assigned the remaining intensities. Data populations are
dynamically updated as data from new acquisitions is accumulated.
A saturation level of 100% spreads the intensity variation across the entire distribution; at lower saturation levels the
intensity will saturate (become brighter) at the percentage value specified. Lowering this percentage causes the pixels to
be saturated at a lower population and makes visible those events rarely seen at higher saturation levels.
Persistence Time
Persistence time is the duration of time (in seconds) after which persistence data is erased from the display.
Check Show Last Trace to keep the last trace superimposed over the persistence display.
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