The invention provides a portable ultrasonic imaging probe directly connectable to an off-the-shelf laptop computer. The probe produces raw digitized data comprising envelope detected ultrasound echo data from an array of ultrasound transducers, and transmits the data to the host computer thereby enabling the host computer to form real-time ultrasonic images of human tissue without the need for any additional electronics. In particular embodiments, the probe includes a plurality of transmit switches configured to connect a transmitting group of the ultrasound transducers to a pulser； a plurality of receive switches configured to connect a receiving group of the ultrasound transducers to analog summing, amplification and signal processing circuitry； and a transmit/receive controller which selects which of said ultrasound transducers are in the transmitting group and which of said ultrasound transducers are in the receiving group. The ultrasound transducers may be conventional or micromachined ultrasound transducers.
