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DTG5078 & DTG5274 & DTG5334 Data Timing Generator User Manual 2
1-29
Set the following in the dialog box:
Table 1-5: PRBS/PRWS dialog box settings
Items
Description
Type
PRBS:
Pseudo random bit sequence, a random pattern with a width of
1 bit. If you specify a range of two or more bits, the same pattern is
created for all the bits.
PRWS:
Pseudo random word sequence, a two-dimensional random
pattern that consists of those patterns generated with the PRBS that are
arranged in the bitwise direction, starting at the LSB.
Pattern
The 14 patterns below are available. The register numbers are assigned,
beginning at the register that will contain the feedback (Register 1). All the
registers are initialized to 1 before calculation. For the shift register
representations and the actual register image, see Figure 1-19 on page 1-28.
PRBS5: X^5+X^4+X^2+X^1+1
PRBS6: X^6+X^5+X^3+X^2+1
PRBS7: X^7+X^6+1
PRBS8: X^8+X^7+X^3+X^2+1
PRBS9: X^9+X^5+1
PRBS9: X^9+X^8+X^5+X^4+1
PRBS10: X^10+X^7+1
PRBS11: X^11+X^9+1
PRBS11: X^11+X^8+X^5+X^2+1
PRBS12: X^12+X^9+X^8+X^5+1
PRBS13: X^13+X^12+X^10+X^9+1
PRBS14: X^14+X^13+X^10+X^9+1
PRBS15: X^15+X^14+1
PRBS23: X^23+X^18+1
Note: The pattern length of the PRBS23 is 8388608–1. The DTG5078
can create pattern data up to 8,000,000 vectors. Due to multiplier
constraints of the DTG5274, output is not available with some clock
frequency and data format settings.
Mark Density
PRBSn is a random pattern of 0s and 1s whose pattern cycle period is
2
n
–1 (n = number of registers. In above Pattern, n = 5 to 23).
Mark Density varies the percentage of 1s (= marks) in the cycle.
Suppose that the pattern obtained by Left Rotating n patterns of PRBSn
patterns (it shifts to the left by n piece, and a part to have overflowed is
attached to the tail end) is PRBSn
n
and the pattern obtained by Left
Rotating 2n patterns of PRBSn patterns is PRBSn
2n
. If PRBSn is ANDed
with PRBSn
n
or PRBSn
2n
, this decreases the percentage of 1s. If it is
ORed with them, this increases the percentage. Mark Density accepts
1/8 to 7/8. The following expressions are used to obtain the value:
1/8: PRBSn & PRBSn
n
& PRBSn
2n
1/4: PRBSn & PRBSn
n
1/2: PRBSn
3/4: PRBSn | PRBSn
n
7/8: PRBSn | PRBSn
n
| PRBSn
2n
Содержание DTG5078
Страница 4: ......
Страница 10: ...Table of Contents iv DTG5078 DTG5274 DTG5334 Data Timing Generator User Manual 2...
Страница 19: ...Reference...
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Страница 24: ...Operating Modes 1 4 DTG5078 DTG5274 DTG5334 Data Timing Generator User Manual 2...
Страница 34: ...Data Structure 1 14 DTG5078 DTG5274 DTG5334 Data Timing Generator User Manual 2...
Страница 58: ...Pattern Edit 1 38 DTG5078 DTG5274 DTG5334 Data Timing Generator User Manual 2...
Страница 88: ...Timing Parameters 1 68 DTG5078 DTG5274 DTG5334 Data Timing Generator User Manual 2...
Страница 100: ...DC Output 1 80 DTG5078 DTG5274 DTG5334 Data Timing Generator User Manual 2...
Страница 120: ...Jitter Generation 1 100 DTG5078 DTG5274 DTG5334 Data Timing Generator User Manual 2...
Страница 126: ...DTG5000 Configuration Utility 1 106 DTG5078 DTG5274 DTG5334 Data Timing Generator User Manual 2...
Страница 146: ...Pulse Generator mode 1 126 DTG5078 DTG5274 DTG5334 Data Timing Generator User Manual 2...
Страница 150: ...Offline mode 1 130 DTG5078 DTG5274 DTG5334 Data Timing Generator User Manual 2...
Страница 176: ...Diagnostics and Calibration 1 156 DTG5078 DTG5274 DTG5334 Data Timing Generator User Manual 2...
Страница 177: ...Appendices...
Страница 178: ......
Страница 186: ...Appendix B System Recovery B 4 DTG5078 DTG5274 DTG5334 Data Timing Generator User Manual 2...
Страница 189: ...Index...
Страница 190: ......
Страница 196: ...Index Index 6 DTG5078 DTG5274 DTG5334 Data Timing Generator User Manual 2...