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168 Chapter 13
cdma2000 Measurement Application
Measurements
Description Specifications Supplemental Information
Modulation Accuracy (Composite
Rho)
BTS Measurements
−25 dBm ≤ ML
a
≤ −15 dBm
20 to 30° C
a. ML (mixer level) is RF input power minus attenuation
RF input power range is accordingly
determined to meet Mixer level.
Specifications apply to BTS for 9 active
channels as defined in 3GPP2, and
where the mixer level (RF input power
minus attenuation) is between −25 and
−15 dBm.
Composite EVM
Range
0 to 25%
Floor 1.6%
Accuracy
b
b. The accuracy specification applies when the EVM to be measured is well above the measurement floor.
When the EVM does not greatly exceed the floor, the errors due to the floor add to the accuracy errors.
The errors due to the floor are noise-like and add incoherently with the UUT EVM. The errors depend
on the EVM of the UUT and the floor as follows: floorerror = sqrt(EVMUUT
2
+ EVMsa
2
) −
EVMUUT, where EVMUUT is the EVM of the UUT in percent, and EVMsa is the EVM floor of the
analyzer in percent. For example, if the EVM of the UUT is 7%, and the floor is 2.5%, the error due to
the floor is 0.43%.
±1.0%
0.5%
at EVM measurement in the range of
12.5% to 22.5%
Composite Rho
Range
0.9 to 1.0
Floor 0.99974
Accuracy ±0.0010
±0.0030
at Rho 0.99751 (EVM 5%)
at Rho 0.94118 (EVM 25%)