Measurement Errors
Meas. mode:
Scope
Eye
Jitter
TDR
Flex Apps:
FlexDCA
FlexRT
If a measurement cannot be made the string "9.91E+37 (NaN)" is returned as the measurement result. Negative infinity is reported as −9.9E+37 (−Infinity). Examples that cause this situation to occur include:
- Lack of data
- The signal is clipped
- The source signal is not displayed
- The requested measurement is not possible (for example, a period measurement on an FFT waveform)
Use a measurement command's :STATus? child query to determine if a measurement was correctly performed. If not, use the :STATus:REASon? child query to return a message string that helps to identify the cause. The following table shows some of the common response strings.
| Query Response | Description |
|---|---|
| Oscilloscope and Eye Mode Measurements | |
| Edge? | The required edge was not found. |
| Voltage? | The requested amplitude was not found. |
| Top = Base | The waveform top and base are equal. |
| Incomplete | The completion criteria has not been met. |
| Clipped Hi | The waveform is clipped at the top of the display. |
| Clipped Low | The waveform is clipped at the bottom of the display. |
| Too Small | The input signal is too small. |
| Lower? | The lower threshold is not on the waveform. |
| Upper? | The upper threshold is not on the waveform. |
| Thresholds? | The upper and lower thresholds are too close. |
| Time? | The requested time is not on the waveform. |
| Time? | The requested time was not found. |
| Left? | The left bounding data point was not found. |
| Right? | The right bounding data point was not found. |
| Top? | The specified eye top is not on the waveform. |
| Base? | The specified eye base is not on the waveform. |
| Eye? | Unable to identify the eye. |
| Crossings? | Not enough crossings were found. |
| No data | Not enough samples have been acquired. |
| Source off | The source is turned off. |
| Source? | The source waveform is not in the correct format. |
| Jitter? | The jitter is too large. |
| Period? | The measurement period is too small. |
| Transition? | The measurement transition is too small. |
| Width? | The measurement pulse width is too small. |
| Cross? | The crossing is too thin. |
| Dark Level? | The dark level is invalid. |
| Corr Factor? | The Correction Factor is larger than the measured ER. |
| Mismatch | Not all waveforms were acquired simultaneously. |
| Cal Req'd | {0} requires calibration. |
| DFE? | The measurement is not defined for the output of a DFE. |
| Jitter Mode Measurements | |
| Level? | Sample level is out of valid range. |
| Jitter | Excessive Jitter. |
| Pattern | Incorrect pattern parameters. |
| Eye? | Eye is closed. |
| Edge? | Too many points outside range of the edge model. |
| Clipped | Histogram is clipped. |
| Edge? | Unable to create monotonic edge model. |
| Edges? | No suitable edges for measurement. |
| Jitter | One/Zero level measurements may be corrupted by excessive jitter. |
| RJ Comp? | The RJ Compensation Factor is too large. |
| RN Comp? | The RN Compensation Factor is too large. |
| JSA-RJ? | Jitter Spectrum Analysis is reporting an RJ value that is too large. |
| RN Comp? | Unable to apply RN Compensation/Stabilization using current Jitter Data. |