IQ Modulator Amplitude Balance and Phase Shift Tuning

The purpose of this tuning operation is to adjust the I/Q modulator d.c. offsets and the I/Q modulator amplitude balance and phase shift.

I/Q modulator d.c. offsets, amplitude balance and phase shift tuning:

- Select I/Q tuning values from PC's memory, phone's EEPROM or factory default values.

- Connect spectrum analyzer (with attenuator if needed) to phone antenna connector.

- Check that TX power level is level 15, Cont. mode channel is 60 and TX data type is 1.

- Adjust spectrum analyzer centre frequency to 902 MHz, Span 200 kHz, Res BW 10 kHz, Video BW 1 kHz and Sweep time 0.5 s.

- Adjust the level of centre frequency (CHF signal) to minimum by varying D/A converter value with <- and -> buttons.

- The amplitude difference between CHF-67.7 kHz and CHF should be >30 dB.

- Adjust the level of signal CHF to minimum by varying D/A converter value with <- and -> keys.

-67.71 kHz

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