An apparatus and method for generating high quality, high frame rate images in a handheld or hand-carried ultrasound imaging machine. The apparatus includes a time-multiplexed beamformer coefficient generator that supplies the necessary delay and weight coefficients to process multiple beams in parallel via a beamforming coefficient bus. This approach reduces the required hardware and power consumption to satisfy the physical space and power requirements of a handheld probe. The ultrasound machine may optionally turn off or operate beamformers in a standby mode. The ultrasound machine may also use pulse inversion harmonics to improve image quality by improving signal-to-noise ratio.