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Appendix B: Automatic Measurements Reference
CSA8000B & TDS8000B User Manual
B-51
Table B- 8: NRZ Measurements - Timing (cont.)
Name Definition
NRZ Delay The time interval between the crossings of the mid-reference levels on the t wo sources of the
measurement.
NRZ Delay = Tcross(source1) – Tcross(source2)
Where Tcross is t he positive or negati ve crossing ti me at mid-reference level.
The mid-reference level is adj ustable and defaults to 50% of the NRZ eye amplitude. See NRZ
Crossings on page B--64.
If enabled, measurement gates constrain the measurement region to the area between the Start
Gate (G1) and Stop Gate (G2). See To Localize a Measurement on page 3--83.
By default, for each source, the algorithm searches forward from the Start Gate, but the
Direction of traversal can be reversed, so that the search will be backward from the Stop Gate.
This measurement requires the use of a waveform database. When this measurement is turned
on, it will automat ically set the measurement system to use a waveform database if available.
NRZ Duty Cycle
Distortion
The ratio of the time interval between the points where the rising and the falling edges cross the
mid-reference level and t he NRZ bit time.
Where Tcross1 and Tcross2 are the mean of t he histogram of t he two consecut ive eye
crossings, and Trise and Tfall and the time points where the rising and falling edges cross
the mid-reference level. See NRZ Crossings on page B--64.
The mid-reference level is adj ustable and defaults to 50% of the NRZ eye amplitude.
If enabled, measurement gates constrain the measurement region to the area between the Start
Gate (G1) and Stop Gate (G2).
This measurement requires the use of a waveform database. When this measurement is turned
on, it will automat ically set the measurement system to use a waveform database if available.
See Use a Waveform Database on page B--70.
NRZ Duty Cycle Distortion = fabs
Ꮛ
(Trise − Tfall)
(Tcross2 − Tcross1)
Ꮠ
NRZ Eye Width The 3σ guarded delta between two consecutive eye crossings.
Eye Width = (Tcross2 – 3 * Tcross2σ) – (Tcross1 + 3 * Tcross1σ)
where Tcross1 and Tcross2 are the mean of the histogram of the two crossings.
This measurement requires the use of a waveform database. When this measurement is turned
on, it will automat ically set the measurement system to use a waveform database if available.