Universal ultrasound sigma-delta receiver path

In a receive beamformer system for ultrasound information, an improvement comprising:

• a first receive beamformer channel comprising a sigma-delta analog-to-digital converter, the first receive beamformer channel operable for both continuous wave Doppler and pulsed B-mode signals;
• wherein the first receive beamformer channel further comprises a DC correction feedback circuit from an output of the sigma-delta analog-to-digital converter to an input of the sigma-delta analog-to-digital converter;
• and
• wherein the DC correction feedback circuit is operable to update a DC correction value output to the input of the sigma-delta analog-to-digital converter between receive cycles.

In a receive beamformer system for ultrasound information, an improvement comprising:

• a first receive beamformer channel comprising a sigma-delta analog-to-digital converter, the first receive beamformer channel operable for both continuous wave Doppler and pulsed B-mode signals;
• wherein the first receive beamformer channel further comprises a first filter operable to construct first samples with a greater bit width than output from the converter;
• and
• further comprising:
• at least a second receive beamformer charnel;
• a summer operable to sum outputs from the first and second receive beamformer channels;
• a second filter operable to construct second samples from an output of the summer, the second samples having a greater bit width than the first samples;
• and
• a communications interface operable to transmit the second samples to a remote imaging system.

A method for receive beamforming ultrasound information, the method comprising:

• receiving continuous wave Doppler and B-mode ultrasound signals in a first channel;
• converting the continuous wave Doppler and B-mode ultrasound signals in the first channel from analog-to-digital by oversampling;
• and
• beamforming from the converted continuous wave Doppler and B-mode ultrasound signals;
• wherein the continuous wave Doppler ultrasound signals have a bandwidth less than 50 KHz and the B-mode ultrasound signals have a bandwidth greater than 50 KHz, and wherein the sigma-delta analog-to-digital converter is operable at an oversampling ratio corresponding to a dynamic range of the continuous wave Doppler ultrasound signals greater than 70 dB and a dynamic range of the B-mode ultrasound signals greater than 60 dB.

A receiver system for ultrasound information, the receive beamformer system comprising:

• a plurality of a sigma-delta analog-to-digital converters;
• a first summer operable to combine the ultrasound information from the sigma-delta analog-to-digital converters;
• conductors operable to bypass the first summer with the ultrasound information from the sigma-delta analog-to-digital converters;
• and
• switches operable to select between the first summer and the conductors as a function of element impedance.

A method for receiving ultrasound information from different sized transducer elements, the method comprising:

• providing a plurality of sigma-delta analog-to-digital conversion paths;
• using the paths separately as receive beamformer channels for connection with first transducer elements;
• and
• summing the ultrasound information from multiple ones of the paths as a receive beamformer channel for connection with a second transducer element, the second transducer element having a lower impedance than one of the first transducer element.