Egsm 900 Calibration Items - LG U8290 Service Manual

7.3.3 EGSM 900 Calibration Items

A. GSM Ramp Up/Down Calibration
- Purpose
This item contains the GSM normal Tx burst up/down-ramp DAC values for each power level.
When a GSM Tx burst is generated, it shall pass the ETSI standard power mask as well as Output RF
Spectrum due to Modulation and Switching (OSRF).
- Procedure Proposal
1. Set phone to GSM mode. Determine the DAC codes for each power level during steady state (flat
part of the burst). Each power level has a tolerance limit as shown in Table 7-1.
2. Let's call X the power levels and Y(x) (i) the up ramp DAC value of X power level at iteration i ( we
have 30). We then have the following:
NV_GSM_TX_BURST_UP_RAMP_INDEX_X = (X, Y(x) (i) ), where X is a power level For
Power Control Level X= 5 to 19
For i = 1 to 30 (Number of step for Ramp Up)
NV_GSM_TX_BURST_UP_RAMP_INDEX_X[X, Y(x) (i)] = GSM_PA_DAC_CODE[X] - DAC
Table [X,Y(x) (i)]
Next i
Next x
3. Turn PA off
4. Write NV_GSM_TX_BURST_UP_RAMP_INDEX_X[X, Y(x) (i)] to an NV file.
Power Passing Limits
Control Level (tolerances)
±0.2 dB
5 (33 dBm)
±0.4 dB
6 (31 dBm)
±0.4 dB
7 (29 dBm)
±0.4 dB
8 (27 dBm)
±0.4 dB
9 (25 dBm)
±0.4 dB
10 (23 dBm)
±0.4 dB
11 (21 dBm)
±0.4 dB
12 (19 dBm)
±0.4 dB
13 (17 dBm)
±0.4 dB
14 (15 dBm)
±0.4 dB
15 (13 dBm)
±0.5 dB
16 (11 dBm)
±0.5 dB
17 (9 dBm)
±0.5 dB
18 (7 dBm)
±0.5 dB
19 (5 dBm)
Table 7-1. Tolerances for each power level
- 177 -
7. CALIBRATION
PA DAC code[x]
(RF Cal Station)
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x