23- 5
FFT Commands
The :MEASure:FFT commands control the FFT measurements that are
accessible through the Measure subsystem.
Measurement Setup
To make a measurement, the portion of the waveform required for that
measurement must be displayed on the oscilloscope.
• For a period or frequency measurement, at least one and a half
complete cycles must be displayed.
• For a pulse width measurement, the entire pulse must be displayed.
• For a rise time measurement, the leading (positive-going) edge of the
waveform must be displayed.
• For a fall time measurement, the trailing (negative-going) edge of the
waveform must be displayed.
In jitter mode with jitter statistics enabled, measurements are made on
all data regardless of what is on screen.
User-Defined Thresholds
If you choose to set user-defined thresholds, they must be set before
actually sending the measurement command or query.
Measurement Error
If a measurement cannot be made because of a lack of data, because the
source waveform is not displayed, the requested measurement is not
possible (for example, a period measurement on an FFT waveform), or
for some other reason, the following results are returned:
• 9.37 is returned as the measurement result.
• If SENDvalid is ON, the error code is also returned.
Making Measurements
If more than one period, edge, or pulse is displayed, time measurements
are made on the first, left-most portion of the displayed waveform.
When any of the defined measurements are requested, the oscilloscope
first determines the top (100%) and base (0%) voltages of the waveform.
From this information, the oscilloscope determines the other important
voltage values (10%, 90%, and 50% voltage values) for making
measurements.
The 10% and 90% voltage values are used in the rise time and fall time
measurements when standard thresholds are selected. The 50% voltage
value is used for measuring frequency, period, pulse width, and duty
cycle with standard thresholds selected.
Summary of Contents for Infiniium 8000A
Page 1: ...Agilent Technologies Infiniium 8000A Programmer s Reference ...
Page 2: ......
Page 20: ...Contents 16 ...
Page 21: ...1 Introduction to Programming ...
Page 43: ...2 LAN and GPIB Interfaces ...
Page 53: ...3 Message Communication and System Functions ...
Page 58: ...3 6 ...
Page 59: ...4 Status Reporting ...
Page 78: ...4 20 Figure 4 3 Status Reporting Decision Chart ...
Page 79: ...5 Programming Conventions ...
Page 84: ...5 6 Programming Conventions The Command Tree Figure 5 1 Command Tree ...
Page 85: ...5 7 Programming Conventions The Command Tree Figure 5 2 Command Tree Continued ...
Page 86: ...5 8 Programming Conventions The Command Tree Figure 5 3 Command Tree Continued ...
Page 87: ...5 9 Programming Conventions The Command Tree Figure 5 4 Command Tree Continued ...
Page 88: ...5 10 Programming Conventions The Command Tree Figure 5 5 Command Tree Continued ...
Page 89: ...5 11 Programming Conventions The Command Tree Figure 5 6 Command Tree Continued ...
Page 94: ...5 16 ...
Page 95: ...6 Sample Programs ...
Page 149: ...7 Acquire Commands ...
Page 176: ...7 28 Acquire Commands SRATe AUTO ...
Page 177: ...8 Bus Commands ...
Page 187: ...9 Calibration Commands ...
Page 195: ...10 Channel Commands ...
Page 223: ...11 Common Commands ...
Page 247: ...12 Digital Commands ...
Page 254: ...12 8 ...
Page 255: ...13 Disk Commands ...
Page 300: ...13 46 Disk Commands STORe Obsolete ...
Page 301: ...14 Display Commands ...
Page 322: ...14 22 ...
Page 323: ...15 External Trigger Commands ...
Page 343: ...16 Function Commands ...
Page 382: ...16 40 ...
Page 383: ...17 Hardcopy Commands ...
Page 391: ...18 Histogram Commands ...
Page 403: ...19 InfiniiScan ISCan Commands ...
Page 421: ...20 Limit Test Commands ...
Page 429: ...21 Marker Commands ...
Page 452: ...21 24 ...
Page 453: ...22 Mask Test Commands ...
Page 499: ...23 Measure Commands ...
Page 636: ...23 138 Measure Commands VUPPer ...
Page 637: ...24 Pod Commands ...
Page 642: ...24 6 ...
Page 643: ...25 Root Level Commands ...
Page 645: ...25 3 STORe SETup STORe WAVeform TER Trigger Event Register VIEW ...
Page 674: ...25 32 ...
Page 675: ...26 Self Test Commands ...
Page 679: ...27 System Commands ...
Page 694: ...27 16 ...
Page 695: ...28 Time Base Commands ...
Page 708: ...28 14 ...
Page 709: ...29 Trigger Commands ...
Page 822: ...29 114 ...
Page 823: ...30 Waveform Commands ...
Page 893: ...31 Waveform Memory Commands ...
Page 902: ...31 10 ...
Page 903: ...32 Error Messages ...
Page 914: ...32 12 ...