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S:\Hp8960\E1962B CDMA 2000\Pi Release\Reference Guide\Chapters\cdma2000_meas_gpow_desc.fm
Gated Power Measurement Description
Data points return power levels, relative to the average power during the middle of the burst, that correspond
with time intervals before, during, and after the burst.
The gated power measurement analyzes the rising and falling edges of the burst to determine where the -3 dB
points are. Using the -3 dB points to determine the center of the burst, the test set positions the measurement
mask (green lines on the display) to align in time with the center of the burst.
Since the middle portion of the burst is compressed in time, the scaling is different when compared to the
rising or falling portions. The following formulas can be used to calculate the time associated with each data
point from 0 to 5,264 as returned by the “FETCh:GPOWer:TRACe?” command:
Equation 1. Time Association For Data Points 0 through 370
where t1 is the sampling period for each data point, and p is the data point of interest (from 0 to 5,264).
Equation 2. Time Association For Data Points 371 through 4893
where t1 is the sampling period for each data point, and p is the data point of interest (from 0 to 5,264).
Equation 3. Time Association For Data Points 4894 through 5264
where t1 is the sampling period for each data point, and p is the data point of interest (from 0 to 5,264).
NOTE Data point 222 corresponds with time 0 on the gated power graph.
On the test set’s display, data points are graphed as follows:
• For the rising trace, data points 0 through 370 (the first 371) are displayed with each data point occupying
one display pixel.
t1 p 222–()×
t1 1 12 1.2288 10
6
××()⁄ 67.82nS≈=
4 t1 p 2667–()8÷()××
t1 1 12 1.2288 10
6
××()⁄ 67.82nS≈=
t1 p 13347+()×
t1 1 12 1.2288 10
6
××()⁄ 67.82nS≈=
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