Test 121 - 123 Tn Rx If Agc Rxdbctr (0) [Or (1) Or (2)] - Nokia RH-17 Series Troubleshooting - Rf

CCS Technical Documentation
Manual Verification:
In Phoenix, use the RF Main Mode window to set the AMPS transmitter to channel 384.
Using the PDM Control window, set the I and Q DC offsets to 0,0 by entering 0,0 in the
"values" edit box.
Center the transmit signal on the spectrum analyzer, set the span to 100 kHz. Lower the
bandwidth so that the two sidetones can be differentiated from the carrier. Measure the
amplitude of the sidetone at 20 kHz above the carrier. The amplitude of the sidetone will
probably be higher than that of the carrier. The amplitude should be within the test lim-
its.
Troubleshooting:
If the carrier is not present, troubleshoot the cell TX chain using the "things to check" list
and probing tables/diagrams. If the two tones offset at 20 kHz are not present on the TX
signal, check to see if they are on Robin output at L613 at 836.52 MHz + 20 kHz. If not,
there is likely a problem with N601 (Robin). Ensure power supplies to Robin (VR2, VR3,
VR6 and VIO) are correct. Check components around Robin. If still failing, replace Robin.

Test 121 - 123 TN RX IF AGC RXdBCtr (0) [or (1) or (2)]

Description:
This tuning calibrates the RX IF AGC curve, because the output power of the IF part of
the Batman IC is not a linear function of RX_IF_AGC. The tuner injects three known sig-
nal power levels into the phone's receiver, and for each one the phone's AGC algorithm
adjusts the RX_IF_AGC to get the same amplitude at the output of Batman, although
different amplitudes are going in. From these three points, curve fitting is used to inter-
polate between measurement points.
Explanation of Result:
The result is a value of RxdBCtr (which corresponds to a value of RX_IF_AGC) for each of
three CW input powers injected into the receiver:
-87.5 dBm
-57 dBm
-18 dBm
Manual Verification:
With the phone in local mode, use the Main Mode window to turn on the AMPS receiver
set to channel 384. Using the RF Tuning window, perform the manual tuning three times,
each time injecting the CW signal at the amplitudes listed above, one amplitude per tun-
ing. Each time record RxdBCtr, which is returned by Phoenix during the manual tuning.
Troubleshooting:
While injecting a signal into the receiver, check the values of RSSI and RX_IF_AGC PDM
value and, if needed, voltage. RSSI should be within +/- 2 dB of the actual power in dBm
on the RF connector. Table 3a lists limits and typical values. The AGC will try to keep the
Issue 1 04/2003
Nokia Corporation
Troubleshooting — RF
Confidential
RH-17
Page 39