LG U8210 Service Manual page 183

7. CALIBRATION
H. RX LNA Freq. Calibration
- Purpose
This item contains 15 adjustment values relative to the reference frequency for the
NV_WCDMA_LNA_RANGE_OFFSET item. These NV values should be considered as adjustments
for gain variation of the LNA gain step based on the frequency index. These values are represented by
an 8-bit signed number. The values are the change between the reference frequency LNA gain-step
and the LNA gain-step at the frequency index of interest.
- Procedure Proposal
1. Set phone in WCDMA mode.
2. Set LNA offset 1 to zero.
3. Set phone to a reference channel (a reference channel usually is in the middle of the band).
4. Set signal generator frequency to a reference channel plus an offset of 685 kHz.
5. Set Rx Power at phone antenna connector to the mid-point of LNA_RISE_1 and LNA_FALL _1
((LNA_RISE_1 + LNA_FALL_1)/2).
a. Load calibrated and frequency compensated DVGA for index [i]
b. Set LNA in state 0.
c. Read and store RSSI in (A[i])
d. Set LNA in state 1.
e. Read and store RSSI in (B[i])
f. Store NV_WCDMA_LNA_OFFSET_VS_FREQ[i] = (A[i]-B[i]) -
NV_WCDMA_LNA_RANGE_OFFSET
6. Repeat steps
a. through f. for all 15 frequencies and set reference frequency to a value of 0
Reference documents
QUALCOMM, MSM6200 WCDMA RF NV Items (80-V5216-3 Rev. C)
QUALCOMM, MSM6200 GSM RF NV Items (80-V5216-2 Rev. A)
QUALCOMM, MSM6250 TM RF NV Items (80-V4690-25 Rev. C)
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