A patient interface module (PIM) for an intra-vascular ultrasound (IVUS) imaging system and a method for using it are provided. The PIM may include a motor having position sensors； a motor controller circuit providing a signal to the motor； and a clock and timing circuit to provide a trigger signal to a pulse transmitter circuit and a reference clock signal to an analog to digital converter (ADC) circuit, the trigger signal and the reference clock signal synchronized to a local oscillator； wherein the motor is configured to provide a relative phase value between a motor shaft and the local oscillator to a data processing circuit.
