Maxim Integrated HFAN-09.5.0 User Manual
Application Note:
FAN-
H
9.5.0
Rev.1; 04/08
Pattern Creator/Converter Software
User
Manual
AVAILABLE
Patte
rn Creator/Converter Software User Manual
1 Introduction
The Pattern Creator/Converter software (available
for download at: http://www.maxim-
ic.com/tools/other/) was written to facilitate the
r
eation and use of complicated and non-standard
c
test patterns for evaluation of ICs, modules, and
systems used in fiber-optic, video, backplane and
other applications. This application note will step
through the features and use of the Pattern Creator /
Converter software and show examples on how to
use the program. The software has three main
sections: a Pattern Creator, a Pattern Converter and
Additional Resources / Information.
Note: This software is intended to run on a
windows-based desktop computer (Windows 98 or
newer) with a screen resolution of 800x600 or
larger. The operating system that is included with
test equipment (pattern generators, oscilloscopes,
etc.) will often lack the necessary installed window
components to allow correct operation of the
program directly on that equipment.
2 Pattern Creator
The Pattern Creator (Figure 1) allows the user to
create long binary test patterns in a text file format.
To start a new pattern, click the Output File Name
button and choose a filename and location. Once the
file location and name are selected, the file is
created. Patterns can then be added sequentially by
pressing the buttons of the various built-in pattern
sequences.
The sequence of the pattern created will appear in
the Pattern Sequence box and the statistics of the
pattern will be displayed in the Pattern Statistics
text box. Pressing the Done button closes the text
file that was created. More details and an example of
how to use the buttons and features of the Pattern
Creator section will be demonstrated in the
following paragraphs.
Figure 1. Pattern Creator Tab Menu
Application Note HFAN-9.5.0 (Rev.1; 04/08) Maxim Integrated
Page 2 of 8
2.1 PRBS Patterns
The Pseudo Random Bit Sequences (PRBS) are
generated using a software version of the
conventional hardware shift register with the taps of
minimum shift algorithms generated from Galoisfield arithmetic (Figure 2, Table 1, see References 1
& 2). The shift register length is determined by the
pattern title. For example, a PRBS 27-1 pattern
would be generated using a shift register 7 bits long.
Where n is the register length, the PRBS pattern
contains every possible combination of n bits
(except one).
PRBS Generation
PRBS Generation
n Bit Shift Register
n n-1 2 13
OUT
SHIFT DIRECTION
TAP1
TAP3
TAP2
TAP4
XOR
Figure 2. PRBS Generation
IN
Table 1: PRBS Pattern Length / Tap Positions
Register
Len
gth
(n)
Pattern
Length
(2n-1) Tap1 Tap2 Tap3 Tap4
Register Number (1 to n)
3 7 3 2
4 15 4 3
5 31 5 3
6 63 6 5
7 127 7 6
8 255 8 7 3 2
9 511 9 5
10 1023 10 7
11 2047 11 9
12 4095 12 9 8 5
13 8191 13 12 10 9
14 16383 14 13 3 2
15 32767 15 14
16 65535 16 14 13 11
17 131071 17 14
18 262143 18 11
19 524287 19 18 14 13
20 1048575 20 17
21 2097151 21 19
22 4194303 22 21
23 8388607 23 18
The mark density (100%*(number of ones / total
bits)) and the transition density (100%*(number of
bit transitions / total number of bits)) of PRBS
patterns are approximately 50%. This approximation
improves as the pattern length (shift register length)
increases. Also, the maximum number of
consecutive identical digits (CIDs) is equal to the
register length (n) (e.g. a 223-1 PRBS has a
maximum of 23 CIDs).
Pressing any of the PRBS buttons opens the option
list shown in Figure 3. Using this option list, the
PRBS sequence can be repeated an integer number
of times or the total number of bits to write of the
given PRBS can be selected. The PRBS can also be
written to the file inverted or non-inverted. It is
important to note that the mark density and the
transition density of the pattern sequence can deviate
from the 50% approximations if only part of the
PRBS is written to the file.
ure 3. PRBS Options
Fig
In this software program, each PRBS register is
initialized with all 1’s. Therefore, each PRBS
sequence will start with the maximum CID length
(e.g. the first seven bits generated from the noninverted PRBS 2^7-1 will be all ones).
Application Note HFAN-9.5.0 (Rev.1; 04/08) Maxim Integrated
Page
3 of 8
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