Dcs 1800 Calibration Items - LG U8290 Service Manual

7.3.4 DCS 1800 Calibration Items

A. DCS Ramp Up/Down Calibration
- Purpose
This item contains the DCS normal Tx burst up/down-ramp DAC values for each power level.
When a DCS 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 DCS 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 7-2.
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_DCS_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_DCS_TX_BURST_UP_RAMP_INDEX_X[X, Y(x) (i)] = DCS_PA_DAC_CODE[X] - DAC
Table [X,Y(x) (i)]
Next i
Next x
3. Turn PA off
4. Write NV_DCS_TX_BURST_UP_RAMP_INDEX_X[X, Y(x) (i)] to an NV file.
Power Passing Limits
Control Level (tolerances)
±3 dB
0 (30 dBm)
±3 dB
1 (28 dBm)
±3 dB
2 (26 dBm)
±3 dB
3 (24 dBm)
±3 dB
4 (22 dBm)
±3 dB
5 (20 dBm)
±3 dB
6 (18 dBm)
±3 dB
7 (16 dBm)
±3 dB
8 (14 dBm)
±4 dB
9 (12 dBm)
±4 dB
10 (10 dBm)
±4 dB
11 (8 dBm)
±4 dB
12 (6 dBm)
±4 dB
13 (4 dBm)
±5 dB
14 (2 dBm)
±5 dB
15 (0 dBm)
Table 7-2. Tolerances for each power level
- 179 -
7. CALIBRATION
PA DAC code[x]
(RF Cal Station)
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x