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E. RSSI Calibration
- Purpose
This procedure calibrates an absolute power level on the antennaagainst a corresponding RSSI value.
This value together with a pre-defined slope figure is then used to calculate the RSSI value of an
arbitrary received antenna power. The formula y=kx+m is used. (Where k is the slope value, x the
RSSI value, y the actual level, and m is an offset value).
- Procedure Proposal
1. Select switched receiver on a mid DCS-Channel.
2. Feed a modulated -68.5dBmsignal, on the same mid DCS Channel to the antenna input. Measure
the RSSI value, calculate the RSSI table, and store it to the memory
(GD_BAND_RXLEVS_DBM_BURST_M[2]) –1 byte.
8.3.5 WCDMA Calibration Items
A. RF VCO Center Frequency Calibration
- Purpose
This procedure is designed to calibrate the RFVCO (Radio Frequency Voltage Controlled Oscillator)
center frequency of the Ericsson RF 2110 (hereafter referred to as the RF 2100) and ensure that all
channels can be reached with sufficient margin.
The objective of the calibration is to determine a CVCO (Center VCO) value that guarantees the
functionality of the RFLO (Radio Frequency Local Oscillator).
- Procedure Proposal
1. Start the VCXO and RFVCO. VCXOCONT is set to its calibrated value, Ericsson AB 2000 DAC3.
2. Measure the loop voltage (WRFLOOP), with the AB 2000 ADC (GPA4), for all CVCO settings, that
is, 0-7. Find a CVCO value that fulfills the requirements on loop voltage for low and high channel. If
there are several CVCO values that fulfill the loop voltage requirements, then the optimum CVCO
value is that that centers the loop voltage within the specified limits.
3. Store the calibrated CVCO value in GD_RF_SYNT_CONFIG_ID.
B. TX Carrier Suppression Calibration
- Purpose
DC offset compensation the carrier, to the wanted signal at the IQ-modulator output.
The leakage is caused by imperfections in the basebandIQ-path and inside the IQ-modulator. It
impairs the modulation accuracy and results in a high vector magnitude (EVM). The outcome of the
calibration is values for RECDCI and RECDCQ that minimize the carrier.
- Procedure Proposal
1. Set the ME in TX mode on mid-channel. Use typical TX settings. Generate 960 kHz square-wave on
both I and Q with amplitude = 8 (sine-wave could be used instead).
Start with the best value from earlier calibrated units on RECDCI on RECDCQ.
- 217 -
8. CALIBRATION
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