A complex transmitter system typically consists of DACs, reconstruction filter network, and I/Q modulator. Besides the gain and phase mismatch contribution, there could also be timing mismatch contribution from each components. For instance, the timing mismatch could come from the PCB trace length variation between the I and Q channels and the group delay variation from the reconstruction filter.

This timing mismatch in the complex transmitter system creates phase mismatch that varies linearly with respect to frequency. To compensate for the I/Q imbalances due to this mismatch, the DAC3482 has group delay correction block for each DAC channel. Each DAC channel can adjust its delay through grp_delayI(7:0) and grp_delayq(7:0) in register config46 and config47, respectively. The maximum delay ranges from 30ps to 100ps and is dependent on DAC sample clock. Contact TI for specific application information. The group delay correction, along with gain/phase correction, can be useful for correcting imbalances in wide-band transmitter system.