Tn Tx Dc Offset Carrier Suppression - Nokia NPD-4 Series Technical Documentation Manual

NPD-4
Troubleshooting — RF
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.

TN TX DC Offset Carrier Suppression

See previous tuning. This step reports the delta between the reference at 836.52 MHz
+ 20 kHz, and the minimum carrier level at 836.52 MHz.
The result is a delta in dB between the reference at 836.52 MHz + 20 kHz, and the mini-
mum carrier level at 836.52 MHz, found by adjusting the DC offsets for I and Q individu-
ally. The delta should be at least 35 dB.
Manual Verification: Set up the phone as in the previous test, and record the reference
power of the offset tone. Measure the delta between the center and offset tones. If the
delta is 35 dB or greater, the phone passes. If less than 35 dB, vary the "I" DC offset on
the "values" line in the RF Tuning window, using the below listed values until the mini-
mum carrier maximum delta is found. Leave Q at 0. On the "values" line, you enter "I,Q".
The values, in decimal, are:
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Nokia Corporation
CCS Technical Documentation
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Confidential Issue 1 02/2003