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The ESA Series L1500A spectrum analyzer AUX VIDEO OUT and AUX IF OUT signals "drop-out" intermittently between sweeps. Is this normal?

Yes, this is normal. The "drop-out" occurs between sweeps only when the analyzer performs a portion of the automatic alignment. Since it is not necessary for the analyzer to perform an alignment between every sweep, the "drop-outs" or "blanking" of these signals appear to be intermittent.

If these signals were not blanked, these outputs would fluctuate erratically during retrace. This would create problems when monitoring the AUX VIDEO OUT with an X-Y recorder or strip-chart recorder.

  • If you are monitoring these signals with an oscilloscope, trigger the oscilloscope from the HI SWP OUT signal and set the oscilloscope sweep time equal to the analyzer's sweeptime.
  • You could also switch off the auto alignment by pressing: Systems, Alignment, Auto alignment off.

If Auto Align Off is selected, the analyzer will meet its specifications in the following instances:

  • When the analyzer is at a constant temperature, within the operating temperature range, for a minimum of two hours.
  • After the analyzer power is switched on for a minimum of 90 minutes, and Align Now All has been run.
  • When Align Now All is run every hour (or if the ambient temperature changes more than 5°C).

This is also explained in the ESA Series L1500A User's and Calibration Guide.