User Manual

TX Spectral Purity Transmit Mask Acceptance Test
July 1999
4-11
SC 4812ET BTS Optimization/ATP – CDMA LMF
PRELIMINARY 2
Background: Tx Mask Test
This test verifies the spectral purity of each BBX2 carrier keyed up at a
specific frequency, per the current CDF file assignment. All tests are
performed using the external calibrated test set, controlled by the same
command. All measurements are through the appropriate TX OUT
(BTS/RFDS) connector.
The Pilot Gain is set to 541 for each antenna and all channel elements
from the MCCs are forward-link disabled. The BBX2 is keyed up, using
both bbxlvl and bay level offsets, to generate a CDMA carrier (with pilot
channel element only). BBX2 power output is set to obtain +40 dBm as
measured at the TX OUT connector (on either the BTS or RFDS
directional coupler).
TX output power is set to +40 dBm by setting BTS power
level to +33.5 dBm to compensate for 6.5 dB increase from
pilot gain set to 541.
NOTE
The calibrated communications test set measures and returns the
attenuation level of all spurious and IM products in a 30 kHz resolution
bandwidth with respect to the mean power of the CDMA channel,
measured in a 1.23 MHz bandwidth, in dB, verifying that results meet
system tolerances at the following test points:
 at least –45 dB @ + 900 kHz from center frequency,
 at least –45 dB @ – 900 kHz from center frequency.
The BBX2 then de-keys and the applicable redundant BBX2 is assigned
to the current TX antenna path under test. The test is then repeated.
The LMF Tests menu list item, TX Mask, performs the Spectral Purity
TX Mask test for a XCVR(s). All measurements are made through the
appropriate TX output connector using the calibrated TX cable setup.
This test is included in the All TX, All TX/RX and Full Optimization
tests.
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