Width-modulated square-wave pulses for ultrasound applications.

Area of Science:

• Ultrasound Technology
• Signal Processing
• Medical Imaging

Background:

• Ultrasound transducer output pressure control is crucial for diagnostic imaging.
• Existing pulse-width modulation (PWM) techniques require optimization for specific ultrasound applications.

Purpose of the Study:

• To develop and validate an optimized PWM method for precise ultrasound transducer output pressure control.
• To improve coded imaging performance by reducing artifacts and side-lobe levels.

Main Methods:

• Developed a modified level-shifted, carrier-comparison PWM strategy tailored for ultrasound.
• Reduced carrier frequency and altered carrier form to trigonometric relationship.
• Applied frequency modulation for frequency-modulated, amplitude-tapered signals.

Main Results:

• Demonstrated arbitrary waveform generation capability via simulation and experimental hydrophone measurements.
• Achieved significant reductions in image artifacts and peak side-lobe levels in coded imaging.
• Experimentally observed 10 and 8 dB reduction in peak side-lobe levels, correlating strongly with simulations.

Conclusions:

• The optimized PWM method enables effective control of ultrasound transducer output pressure for arbitrary waveforms.
• This technique offers substantial benefits for coded imaging, including artifact reduction and improved signal fidelity.
• The findings support the application of this PWM strategy in advanced ultrasound imaging modalities.