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What is the difference between normal and fast power measurements of a CDMA base station?

In the code domain analyzer, both the normal power measurement and the fast power measurement measure the power in each of the 64 Walsh channels relative to the total power in a 1.23 MHz bandwidth centered at the tune frequency of the analyzer. (The normal power measurement and fast power measurement are not an average of multiple Walsh channels).

So, what is the difference?

In normal power measurement, the analyzer measures the time offset and frequency error (Displayed on the top-right corner of the CDMA analyzer screen) and uses their values to optimize the power measurement. This is not done in fast power measurement (this is why it is fast). In fast power measurement, the analyzer uses the value in the "time offset" field to measure the power. You can get to the "time offset" field by following these steps:

  • Select "Controls" in the code domain analyzer screen
  • Select "FP Setup" from the "choices:" menu on the lower-right corner.
  • Select "Time Offset"
  • Enter the desired time offset

You can also use the time offset value from normal power measurement by selecting "Ofs Trnsfer" field. Follow these steps:

  • Select "controls" in the code domain analyzer screen
  • Select "Main" from the "choices" menu.
  • Select "Measurement" and then "Power".
  • Select "Controls"
  • Select "FP Setup"
  • Select "Ofs Transfer"

The time offset value should appear in the "Time Offset" field.

Only the fast power measurement can be used to view the effects of varying the time offset value and trigger delay value on the code domain power measurement. Here is how you change the trigger delay value:

  • Select "Controls" in the code domain analyzer screen
  • Select "Trigger" from the "choices:" menu on the lower-right corner.
  • Select "Trigger Event"
  • Select "Delay" and enter the desired trigger delay

Only the fast power measurement allows you to take the average over multiple time intervals. Follow these steps:

  • Select "Controls" in the code domain analyzer screen
  • Select "FP Setup"
  • Select "Num Avgs" and enter the number of time intervals over which you want to take the average.

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