User Guide

RH-17
Troubleshooting — RF CCS Technical Documentation
Page 36 Nokia Corporation Confidential Issue 1 04/2003
Test 100 -101 TS ACPR Cell - High(Low) Offset
Description:
ACPR (Adjacent Channel Power Ratio) is a measure of band power in the adjacent chan-
nel as compared to the tuned channel, so it is a power delta in dB. Band power is mea-
sured at the center tuned frequency and also at an offset lower (higher) than the center
frequency, and the difference is ACPR. For this test, the offset is -0.9 MHz (+ 0.9 MHz).
Band power is integrated power over a frequency band, rather than at a single frequency.
The bandwidth for the measurement centered at the tuned frequency is the bandwidth
of the signal, which for IS95 is 30 kHz.
Explanation of Result:
Result is ACPR (a power delta) in dB.
Manual Verification:
Set the phone in local mode, and turn on the Cell transmitter set to channel 384. Use the
TX Limiting function in the RF Tuning window to set the transmit power to the maximum
value (within the limits for the "TX Limiting" tuning Test 72). Observe the TX signal on
the spectrum analyzer. If the spectrum analyzer being used has a CDMA personality card,
then ACPR can be read directly off the screen. If not, then set the bandwidth to 30 kHz,
and set the averaging on. Center the marker at 836.52 MHz and note the power in dBm.
Use the offset marker to measure the power at an offset of +/- 0.9 MHz.
Troubleshooting:
If one or more of the AGC values needs a value much higher than normal to achieve
maximum power, then that would indicate that a component in the chain has less gain
(or more loss) than it should, and another component that is compensating for that
could be saturating. Use the AGC information as a guide to troubleshoot the Tx chain as
described in Table 1a, especially being careful to check all decoupling capacitors C633,
C649, C648, C619, C817, C810, C811, and C813. Severely degraded ACPR is detectable
just by looking at the shape of the CDMA curve, therefore you can also probe each point
in the TX chain to see if ACPR becomes degraded at one point.
Tests 103 - 109 TN AMPS PL2 Po Low (LowMid, MidLow, Mid, MidHigh, HighMid, or High)
Description:
This procedure tunes the AMPS transmit Power Level 0 on seven channels by adjusting
TxdBCtr. The channels are: Low= 991, LowMid= 107, MidLow= 245, Mid= 384, MidHigh=
521, HighMid= 660, High=799. The algorithm then interpolates between the measured
points for frequency compensation.
Explanation of Result:
The result is measured transmit power in dBm for power level 0 on each of the seven
channels.