Abstract: The clipping diodes used to limit voltage during medical diagnostic ultrasound imaging operation are used during calibration operation for measuring amplitude and phase differences. The amplitude and phase measurements using clipping diodes as the calibration node may operate at any frequency, including frequencies less than 20 megahertz as well as frequencies above 20 megahertz. By using the diodes already present, a smaller or more compact calibration system may be provided. More simplistic integration may also result.

Abstract: The clipping diodes used to limit voltage during medical diagnostic ultrasound imaging operation are used during calibration operation for measuring amplitude and phase differences. The amplitude and phase measurements using clipping diodes as the calibration node may operate at any frequency, including frequencies less than 20 megahertz as well as frequencies above 20 megahertz. By using the diodes already present, a smaller or more compact calibration system may be provided. More simplistic integration may also result.

Abstract: An ultrasound probe for diagnostic medical ultrasound imaging, including an ultrasound transducer and a circuit having a plurality of states to limit the use of the ultrasound probe. Ultrasound probe use can be limited based on a unique identification number (e.g., selected by means of electrically programmable fuses) assigned to each ultrasound probe. Alternatively, the ultrasound system software monitors and updates the number of times that the ultrasound probe has been used. Another aspect of the invention is directed to an ultrasound system, including an ultrasound probe with multiple states, a circuit to program and to receive state data from the ultrasound probe and interpret the state data, and a cable to communicate state data between the ultrasound probe and the processor.

Abstract: An electronic device placed in series with the probe ground-to-chassis connection. The device comprises a current-detecting element such as a resistor or RC network and may employ frequency-discriminating circuitry to limit only ground current signals below a certain frequency. The detector element triggers either a current limiter or a latching switch to prevent currents exceeding about 20 .mu.A rms from flowing between the probe and the patient. This is achieved by limiting such currents dynamically or by latching the transducer-probe-ground/system-chassis connection in an "open" state. In normal operation, the limiting/latching function is inactive, i.e. it is transparent to the system and the device shunts noise signals to the system chassis to prevent image degradation. The resistance of the device in normal operation may be in the range of about 0.1 to 10 ohms for effective noise reduction (shielding) at operating frequencies at and above 100 kHz.