HP Cable Box 8591C manual Tracking Generator Unleveled Condition

Making Measurements Using Spectrum Analyzer Mode

Stimulus-Response Measurements

Tracking Generator Unleveled Condition

When using the tracking generator, the message TG UNLVL may appear. The TG UNLVL message indicates that the tracking generator source power (SRC PWR ON OFF ) could not be maintained at the user-selected level during some portion of the sweep. If the unleveled condition exists at the beginning of the sweep, the message will be displayed immediately. If the unleveled condition occurs after the sweep begins, the message will be displayed after the sweep is completed. A momentary unleveled condition may not be detected when the sweep time is small. The message will be cleared after a sweep is completed with no unleveled conditions.

The unleveled condition may be caused by any of the following:

•Start frequency is too low or the stop frequency is too high. The unleveled condition is likely to occur if the true frequency range exceeds the tracking generator frequency specification (especially the low frequency speciEcation). The true frequency range being swept may be significantly different than the start or stop frequency annotations indicate, depending on other spectrum-analyzer settings, especially the span (see speciEcations and characteristics in your calibration guide for your instrument). For better frequency accuracy, use a narrower span.

•Tracking peak may be required (use TRACKING PEAK ).

•Source attenuation may be set incorrectly (select SRC ATN MAN AUTO (AUTO) for optimum setting).

•The source power may be set too high or too low, use SRC PWR ON OFF to reset it.

•The source power sweep may be set too high, resulting in an unleveled condition at the end of the sweep. Use PWR SWP ON OFF to decrease the amplitude.

5-22