Teledyne LeCroy ET-PMT - Electrical Telecom Pulse Mask Testing - Manual (Page 9)

Operator's Manual
Create Custom Mask Test
In addition to the standard pulse masks, custom masks can be created by modifying the mask definition file,
D:\Masks\PulseMasksProp.mdb, using Microsoft Access.
A complete mask definition includes:
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Mask definition properties
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Pulse alignment criteria
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Acquisition settings such as waveform averaging and persistence
Mask Definition Properties
Enter values for the properties indicated below in the PulseMasksProp.mdb table,
TelecomStandardsProps:
ID—Index that is automatically generated. Do not enter a value in this field.
Old—For internal use only; leave blank.
Standard—Name of the standard to which the selected mask is associated. For a custom mask, enter a
unique name, which will appear in the list of Standards available on the Electric Telecom dialog.
Legacy Standard—Leave blank.
Symbol—Defined mode within standard (pos, neg, one, zero, transmit, receive).
Bit rate—Bit rate of signal; defines period.
Required Bandwidth—Minimum bandwidth needed to accurately test signal.
Minimum Sample Rate—Minimum sample rate needed to accurately test signal.
Probe—Required probe or adapter; leave blank if none.
Type—Type of signal and how it will be aligned and tested. Valid entries are: Absolute, Absolute + Offset,
Relative, and Relative Peak.
Coding—Type of coding (CMI code mark inversion, AMI alternate mark inversion, etc.); used for information
only.
Pattern Isolation—Bit pattern used to isolate the pulse under test. The syntax is: bbbb/pp/aaa where bbbb is
the symbol values before the desired pattern and aaa is the value of the bits after the desired pattern. For
example, an isolated “one” would look like: 00/1/00. Bipolar pulses are defined as 1 and -1; and CMI is
handled as two bits per unit interval. A CMI 0, for example, would look like: 1/01/0.
V div—The vertical scale required for nominal amplitude in the mask. This voltage is adjusted for relative
masks.
Nom Ampl—The nominal amplitude of the pulse to be tested.
T div—Horizontal scale to have signal in mask.
ET Delay—The time in seconds between the center of the pulse (1/2 bit) and the edge where the trigger is set.
ET Center—The center of the mask in DIV (usually 5.0).
Base Point—Currently not used; leave blank.
Offset Tol (for "Absolute + Offset" type only)—The permitted tolerance to adjust the offset for a better mask fit.
923136 Rev A 7