Advanced Optical Recording Measurement Package (AORM)

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Optical Recording Measurement Package (ORM)

List by nT display of Timing Jitter (timj) measurement of CD-ROM Data Waveform with separate values displayed for each "nT" mark/space width (3T-11T).

Leading Specifications

• Applications: CD-ROM - DVD-MO

• ORM measurements: 17 optical recording, timing, and amplitude measurements

• List by nT display mode: Display a list of measurements indexed by each (nT) pulse width

• Histograms of measurements: Generate histogram bar charats for analysis of parameter value distributions

• Trend analysis of measurements: Generate trand lines of parameter measurement values to study modulation and other time-ordered dependencies

Added Features in AORM

• Five new parameter measurements for evaluating jitter due to intersymbol interface

• OR parameter support for CAV and ZCLV through automatic period determination

• Setup & View wizard for simplified operation

• Modeling of DVD drive functionality (i.e., equalizer, slice, and PLL)

LeCroy's Optical Recording Measurement packages let you perform automated measurements of optically recorded data waveforms. The combination of these measurements -- DVD Channel Modeling (AORM), long DSO memory, advanced triggering features, and a large-screen waveform display -- provides previously unavailable optical recording analysis capabilities.

Up to five parameter values can be displayed simultaneously with statistics such as average, maximum, minimum, and sigma.

Also provided is a unique "List by nT" display mode, which simultaneously provides, for each group of "nT" width pits/spaces, the measurement values such as edge shift, timing jitter, etc.

Histograms of parameter measurements can be selected to discover statistical anomalies not always identifiable from simple statistics, such as the average or standard deviation.

Trend graphs of parameter measurements can also be selected to observe the variation of successive parameter measurements.

In addition to ORM's capabilities, the advanced package, AORM, provides emulation of DVD equalizer, slicer, and PLL processing. This functionality helps you perform clock and jitter measurements independent of a specific integrated circuit, allowing you to concentrate only on optical head or media performance.

AORM also gives you a new Setup and View wizard, which simplifies the setup process and lets you see the waveforms and measurements, with a histogram, trend, or XY plot of the measurements at the press of a button.

To support advanced optical recording drives that have constant angular velocity (CAV) or zone constant linear velocity (ZCLV), the parameter measurements provide automatic determination of the clock period.

These new capabilities are made available by adding the optical recording measurement packages to either the Waverunner or LC DSO series.

Optical Recording Parameters

Optical recording measurement package parameters directly support the pit/space width-based, data-encoding mechanism used in optical recording, by pre-screening waveform pits and spaces into width ranges from 1T to 25T, where "T" is the clock period.

User options include the ability to:

• calculate parameter values for pits, spaces, or both,

• calculate parameter values for pits and/or spaces of a specific "nT" value or range of "nT" values,

• set the voltage threshold level used to determine pit/space widths,

•  automatic determination of the clock period (AORM),

and much more.

Optical Recording "List by nT" Display Mode

Often, it is desirable to view a measurement value for each "n" value for all possible "nT" width ranges simultaneously. The "List by nT" display is provided to accommodate this need. Up to 25 nT values can be displayed simultaneously in this mode.

Advanced Parameters

When writing to a disk, the length of neighboring spaces or pits affects the position and length of a pit or space. This intersymbol interference is due to thermal effects on the media. These AORM parameters enable an engineer to measure and view the beginning and ending edge shift (and sigma) for all the combinations of neighboring pits and spaces simultaneously. A table display is available that cross-tabulates edge shifts vs. preceding and following pit/space widths.  

AORM lets you view and analyze the equalized data, sliced data, and recovered clock using its emulation of the filter, slicer, and PLL.

Model of DVD 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 OR processing function, available in AORM, can perform this processing and lets 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 first-order integrating slicer, and the bandwidth of the phase-lock loop (PLL).

Simple to Use

In AORM, a full-page setup menu lets you specify information about your signal and the measurements to be made, and sets up the scope accordingly. The view wizard allows easy selection of data, a histogram, a trend, or an XY plot of the selected measurements.

AORM simplifies the configuration of your measurements with its setup and view wizard.

Histogram Function

A histogram of any waveform parameter measurement can be displayed. The histogram function produces a bar graph with the vertical axis in units of "Events" and

the horizontal axis in the unit of the parameter being histogrammed (i.e., volts, nanoseconds, etc.). Histograms graphically represent the distribution of parameter measurements, providing insights often not available through standard statistical measurements such as the average and standard deviation, which can be directly measured.

Trend Function

This function provides valuable information regarding the change in measurement results of a parameter over time, or an even more important aspect, the correlation in the shift of two parameters over exactly the same period of time. The effectiveness of the result is not in the displayed value, but in the larger perspective look.

A graph of successive values of any waveform parameter measurement can be generated through the Trend function. The Trend function produces a line graph with the vertical axis representing the values of parameter measurements and the horizontal axis the rank order number (i.e., first parameter measurement calculated, second parameter...) in which each parameter value displayed was calculated.

A few of the measurements available with the ORM package.

*Available only on LT364 and LC series oscilloscopes.