LG U8110 Service Manual page 214

- Procedure Proposal
1. Put the ME in switched TX mode on mid channel in frequency interval 11 for DCS (with random
modulation).
2. Measure the RMS phase error at the RF connector.
3. Tune the phase detector current (IPHD) until the phase error is minimized. If two IPHD settings gave
the same RMS, choose the lowest value. Measure 10 bursts for each value.
4. Calculate and store the IPHD values in GDFS
(GD_IPHD_8Temperature_and_24Channel_Compensation_Band)
5. The offsets in the table are steps in the IPHD Table 8.4 andall offsets refer to the calibrated value
(Trim) at mid channel in room temperature.
0 1 2 3 4
0 -6 -6 -5 -4 -4 -3 -3 -2 -2 -1 -1
1 -6 -6 -5 -4 -4 -3 -3 -2 -2 -1 -1
2 -6 -6 -5 -4 -4 -3 -3 -2 -2 -1 -1
3 -6 -6 -5 -4 -4 -3 -3 -2 -2 -1 -1
4 -6 -6 -5 -4 -4 -3 -3 -2 -2 -1 -1
5 -6 -6 -5 -4 -4 -3 -3 -2 -2 -1 -1
6 -6 -6 -5 -4 -4 -3 -3 -2 -2 -1 -1
7 -6 -6 -5 -4 -4 -3 -3 -2 -2 -1 -1
D. TX Power Calibration
- Purpose
To tune the different DCS power levels of the power amplifier tooutput powers corresponding to values
in GSM 05.05 and calculate the intermediate levels that ensure a good power versus time
performance.
- Procedure Proposal
1. Reset the DIRMOD-block, and select a ‚mid channel using the trimmed value on the capacity array
for VCO tuning and a default IPHD value as phase detector current. Turn on dummy burst
modulation.
2. Use the Multi-burst method to characterize the relation between output power and the DAC-value.
Then store the DAC values that give the closest approximations to the power targets defined in
Table 8-5.
Frequency Interval
5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
Table 8-4. IPHD Compensation for DCS Band
- 215 -
0 0 1 1 2 2
0 0 1 1 2 2
0 0 1 1 2 2
0 0 1 1 2 2
0 0 1 1 2 2
0 0 1 1 2 2
0 0 1 1 2 2
0 0 1 1 2 2
8. CALIBRATION
3 3 4 4 5 5
3 3 4 4 5 5
3 3 4 4 5 5
3 3 4 4 5 5
3 3 4 4 5 5
3 3 4 4 5 5
3 3 4 4 5 5
3 3 4 4 5 5
5
5
5
5
5
5
5
5