Beamformed ultrasonic imager with delta-sigma feedback control
AssigneesThe Regents of the University of Michigan, Q-Dot, Inc.
InventorsSteven R. Freeman, Matthew O'Donnell, Thomas E. Linnenbrink, Marc A. Morin, Marshall K. Quick, Charles S. Desilets
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Abstract
A method and apparatus are provided for reducing distortion in a dynamically delayed digital sample stream of an imaging system. The method includes the steps of delta-sigma modulating an input analog signal of the imaging system at a frequency above the Nyquist frequency of the input analog signal to generate a digital sample stream and changing a length of the sample stream to delay a portion of the sample stream while maintaining synchronism between a delta-sigma modulator and a demodulator of the system.
Claims31
A method of reducing distortion in a dynamically delayed digital sample stream of an imaging system, such method comprising the steps of:
- delta-sigma modulating an input analog signal of the imaging system at a frequency above the Nyquist frequency of the input analog signal to generate a digital sample stream;
- and
- changing a length of the sample stream while maintaining synchronism between a delta-sigma modulator and a demodulator of the system, thereby reducing intermodulation corruptions.
Apparatus for reducing distortion in a dynamically delayed digital sample stream of an imaging system, such apparatus comprising:
- means for delta-sigma modulating an input analog signal of the imaging system at a frequency above the Nyquist frequency of the input analog signal to generate the digital sample stream;
- and
- means for changing a length of the sample stream while maintaining synchronism between the means for delta-sigma modulating and a demodulator of the system, thereby reducing intermodulation corruptions.
Apparatus for reducing distortion in a dynamically delayed digital sample stream of an imaging system, such apparatus comprising:
- a delta-sigma modulator which modulates an input analog signal of the imaging system at a frequency above the Nyquist frequency of the input analog signal to generate the digital sample stream;
- and
- a sample stream controller which changes a length of the sample stream to delay a portion of the sample stream while maintaining synchronism between the means for delta-sigma modulating and a demodulator of the system.
Dependencies are inferred from the claim text.