CCS Technical Documentation
Troubleshooting - RF
RH-3
Issue 1 06/2003
Nokia Corporation Confidential
Page 55
TX IF AGC (PCS)
The TX IF AGC is adjusted so that the
output power is +11 dBm.
Check Jedi (N601) and supporting compo-
nents. Also check D400, which generates
the PDM signals. Check AGC PDM voltages.
Troubleshoot the rest of the transmitter
chain if necessary.
TX RF AGC (PCS)
This tuning characterizes the PCS
TX_RF_AGC.
Check Jedi (N601). Also check D400, which
generates the PDM signals.
TX Limiting (Cell)
This tuning provides an upper limit on
the transmit power while in Cell (or PCS)
IS95 mode. The reason for this is to
ensure that the phone never goes above
the maximum transmit power level.
If the maximum cannot be reached, either a
component in the transmitter has too much
loss, or not enough gain. Troubleshoot the
Cell (PCS) transmitter, with the phone set to
the same channel as the failed channel.
TX Limiting (PCS)
This tuning provides an upper limit on
the transmit power while in Cell (or PCS)
IS95 mode. The reason for this is to
ensure that the phone never goes above
the maximum transmit power level.
If the maximum cannot be reached, either a
component in the transmitter has too much
loss, or not enough gain. Troubleshoot the
Cell (PCS) transmitter, with the phone set to
the same channel as the failed channel.
TS ACPR (Cell or PCS)
Adjacent Channel Power Ratio (ACPR) is
a measure of band power in the adja-
cent channel as compared to the tuned
channel, so it is a power delta in dB.
Band power is measured at the center
tuned frequency and also at an offset
lower (higher) than the center fre-
quency, and the difference is ACPR. For
this test, the offset is - 1.25 MHz
(+ 1.25 MHz).
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. Check all decoupling
capacitors (C614, C615, C605, C603, C602,
C624, C621, C651, C611, C604, C610, C608,
C650, C841, C817, C808, C840, C809,
C803).
PA Detector (PCS)
This tuning determines the output volt-
age of the TX power detector as a func-
tion of transmitted RF power.
If transmitted power levels cannot be
attained, check PCS TX.
ACPR (Cell)
Tunes for adjacent channel power rejec-
tion.
Troubleshoot the Cell TX and also look at
the Cell band TX decoupling capacitors.
RX IF AGC RX dB Ctr
This tuning calibrates the RX IF AGC
curve. The tuner injects three known
signal power levels into the phone's
receiver, and for each one the phone's
AGC algorithms, adjusts the RX_IF_AGC
to get the same amplitude at the output
of Yoda, although different amplitudes
are going in.
While injecting a signal into the receiver,
check the values of RX_IF_AGC PDM value
and, if needed, voltage. RSSI should be
/- 2 dB of the actual power in dBm
on the RF connector. The AGC will try to
keep the same amplitude on Yoda output;
therefore, if the AGC value is larger than
normal, then the AGC is compensating for
loss in the chain prior to the variable gain
amplifier.
Tuning Title
Description
Troubleshooting
