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Reference
GB1400 User Manual 3-5
Word Patterns
This section explains how to create, edit, save, and recall WORD patterns using
front panel controls or the Menu system.
Basics
You may create and save up to ten WORD patterns in battery-backed memory
locations WORD 0 through WORD 9. In addition, the current WORD pattern is
stored in battery-backed memory. In standard units, each of the saved WORDs
and the current WORD can contain up to 16 bits. In Generators and Analyzers
equipped with the 1-Mbit Option, which provides additional battery-backed
memory, each of the saved WORDs and the current WORD can contain up to
64kbits (with fewer memory buffers, larger WORD patterns can be saved).
There are three ways to create GB1400 WORD patterns:
Using front panel controls. This is usually the quickest way to create and edit
short patterns. It also can be a practical way to edit a few bytes in long patterns if
these bytes are located near to each other.
Using the Menu system. Because it provides direct byte addressing, this is often
the best method for editing a few widely scattered bytes in long WORD patterns.
The Menu system also provides the FILL function, used to load a user-specified
8-bit pattern into all bytes, and the ORDER function, used to set the bit-order in
each byte to MSB or LSB first. Thus you can use the Menu system to create long
WORDs with simple bit patterns using its byte fill, order, and editing
capabilities.
Downloading: This is the best way to create long WORDs with complex
patterns. Long WORD patterns may be created on an external controller, using a
text editor or specialized software, and downloaded via the instrument's GPIB or
RS-232 ports. Downloading is the only practical way to create simulations of
SONET, SDH, FDDI or other framed signals.
Creating Word Patterns Using Front Panel Controls
Standard Instruments
Use the following procedure to create WORD patterns using front panel controls
in standard instruments, that is Analyzers and Generators not equipped with the
1-Mbit Option:
1. If you are using a previously saved pattern as the basis for the new pattern,
recall this pattern from memory. (See Recalling Word Patterns).
2. Press the WORD key. The LED in the WORD key will turn on (indicating
that the instrument is in the WORD editing mode) and the display will show
the bit sequence of the current WORD pattern in binary format. The WORD
may contain either one or two bytes, that is 8 or 16 bits. Word length (8 or
16) is displayed after the WORD's bit sequence.