Tektronix 500C Manuel d'utilisateur télécharger pdf (Page 293)

Appendix B: Algorithms

TDS 500C, TDS 600B, & TDS 700C User Manual

B–3

LowRef — the waveform low reference level. Used in fall and rise time

calculations. Typically set to 10%. You can set it from 0% to 100% or to a

voltage level.

Mid2Ref — the middle reference level for a second waveform (or the second

middle reference of the same waveform). Used in delay time calculations.

Typically set to 50%. You can set it from 0% to 100% or to a voltage level.

The oscilloscope also measures several values itself that it uses to help calculate

measurements.

RecordLength — is the number of data points in the time base. You set it with

the Horizontal menu Record Length item.

Start — is the location of the start of the measurement zone (X-value). It is 0.0

samples unless you are making a gated measurement. When you use gated

measurements, it is the location of the left vertical cursor.

End — is the location of the end of the measurement zone (X-value). It is

( – 1.0) samples unless you are making a gated measurement.

When you use gated measurements, it is the location of the right vertical cursor.

Hysteresis — The hysteresis band is 10% of the waveform amplitude. It is used

in , , and  calculations.

For example, once a crossing has been measured in a negative direction, the

waveform data must fall below 10% of the amplitude from the  point

before the measurement system is armed and ready for a positive crossing.

Similarly, after a positive  crossing, waveform data must go above 10%

of the amplitude before a negative crossing can be measured. Hysteresis is useful

when you are measuring noisy signals, because it allows the oscilloscope to

ignore minor fluctuations in the signal.

Other Variables

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Tektronix 500C Manuel d'utilisateur Page 293