LeCroy DDA 7 Zi series, Руководство оператора

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Operator's Manual
WP700Zi-OM-E-RevA
274
Dark Calibration
Dark calibration is a compensation value added to a channel with an optical module. The Dark Cal Level is the
residual power measured by the optical head with no input applied (dark input), and is used by the extinction ratio
measurement. The dark calibration is independent of what type of module is connected to the selected channel,
so an external optical-to-electrical converter can be compensated.
Performing Dark Calibration
1. In the menu bar, touch Vertical , then select a channel from the drop-down menu.
2. Touch the Dark Cal button .
3. A dialog box will appear instructing you to disconnect any optical signal from the channel. Touch the Start
Dark Calibration button when this is done.
4. Dark calibration will be performed, and the dark level will appear in the Dark Cal Level field.
What Can AORM Do?
The Advanced Optical Recording Measurement (AORM) package for LeCroy digital oscilloscopes provides a set
of waveform measurements and mathematical functions for the analysis of optical recording signals. Parameter
measurements allow the categorizing and listing of measurement values in a variety of ways. The math functions
(Histogramming and Trending) enable information to be graphically displayed.
The Advanced Optical Recording Measurement package provides parameter measurements for evaluating jitter
due to intersymbol interface and emulation of DVD’s equalizer, slicer, and PLL. This functionality helps you to
perform clock and jitter measurements, independent of a specific Integrated Circuit, allowing you to concentrate
on optical head or media performance only. To support advanced optical recording drives that have constant
angular velocity (CAV) or zone constant linear velocity (ZCLV), parameter measurements support automatic
determination of the clock period.
Histogramming
Histograms can be created for any waveform parameter. They are displayed based on a set of user settings such
as bin width or number of parameter events to be used. Histogram parameters are provided for measuring
different histogram features such as standard deviation, number of peaks, and most populated bin. Histograms
are selected by defining a trace as a math function, and selecting Histogram as the math function. As with other
Zoom traces, histograms can be positioned and expanded by using the front panel
P
OSITION
and
Z
OOM
knobs.
Trending
The Trend function allows you to create a graph containing successive waveform parameter measurement
values. The trend function provides useful visual information on the variation of a waveform parameter within a
sector, or even over multiple sectors. The Trend functionality, coupled with other scope features, enables you to
graph certain parameters against one another.
Model of Optical Recording Processing
In many applications, it is important to make timing and jitter measurements directly from the RF signal,
independent of a specific DVD chip. The optical recording processing function in AORM can perform this
processing and can let you view the equalized data, sliced data, threshold, and/or the recovered clock. You can
control the cutoff frequency and boost of the equalizing filter, the closed loop bandwidth of the 1st order
integrating slicer, and the bandwidth of the phase-locked loop (PLL).
Selecting Parameters
1. Select Measure from the menu bar,
2. Touch the Px tab for the desired parameter position (P1 to P8).
3. Touch inside the Measure field, then select the Optical Recording group of parameters: