Non-linear harmonic reduction pulse width modulation (HRPWM) for the arbitrary control of transducer-integrated switched excitation electronics

2016 IEEE International Ultrasonics Symposium (IUS)

Carpenter

Freear

et al. 2016

Self Cite

Abstract-Real time in situ characterisation of solids concentration would aid operational understanding and improve efficiency in many industrial systems. This is especially true in the processing of legacy nuclear wastes where hazardous material is encountered. Acoustic methods have been previously demonstrated for the measurement of concentration in solid-liquid systems at a small scale. This study explores the use of the ultrasound array research platform (UARP) for backscatter measurements of concentration at a large scale in a dynamic settling system. The theory of acoustic measurement of solids concentration is described for both backscatter based attenuation and backscatter power methods. Acoustic based backscatter power and attenuation measurements are compared to laboratory analysed samples. Ultrasonic solids concentration analysis is shown to reveal flow dynamics within the settling tank.

Section: Hardware Designmentioning

confidence: 99%

Large-scale trials of a real-time acoustic backscatter system for solids concentration measurement during nuclear waste cleanup

2016 IEEE International Ultrasonics Symposium (IUS)

Carpenter

Freear

et al. 2016

Self Cite

“…Excitation waveform characteristics are controlled through precise timing of the transitions between switched voltage levels allowing cancellation of harmonics [6], precise amplitude control [7] and synthesis of arbitrary waveforms [8].…”

Section: Hardware Designmentioning

confidence: 99%

“…The transducer was consecutively excited with three different waveforms of frequency 2.00, 2.25 and 2.50 MHz, of duration 10 µs and ±100V and Hann windowing. The waveforms were encoded as using five discrete voltage levels [7]. In total 10,000 received waveforms were collected for each excitation waveform and sored for post-processing.…”

Section: Experimental Investigationmentioning

confidence: 99%

Development of a real-time acoustic backscatter system for solids concentration measurement during nuclear waste cleanup

2015 IEEE International Ultrasonics Symposium (IUS)

Freear

Peakall

et al. 2015

Self Cite

Abstract-The measurement of the concentration of solid particles in suspension without physical sampling is a necessary tool for the nuclear industry involved with cleanup of a significant quantity of legacy waste in the form of sludge. This paper presents the work of a project to develop acoustic instrumentation for the in-situ characterization of such sludge. The measurement principle and signal processing employed is presented along with the design of a custom acoustic instrument for deployment in nuclear and industrial environments. The paper presents experimental results demonstrating the ability of the technique for the online measurement of mass concentration in a suspension of glass power in water.

“…Control of excitation parameters allows the development of methods such as transmit pre-distortion [7], subharmonic imaging [8], superharmonic imaging [9] and microbubble manipulation [10]. This paper explores the application of Harmonic Reduction Pulse Width Modulation (HRPWM) [11]- [13] switched excitation using commercial transmit front end integrated circuits The HRPWM technique allows that control of excitation amplitude, and hence ultrasonic wave pressure, by defining two waveforms with varying switching angles δ 1 and δ 2 as illustrated in figures 1a and 1b [11], [12]. The amplitude of the fundamental and harmonics are controlled by adjusting modulation carrier waveforms.…”

Section: Introductionmentioning

confidence: 99%

Performance of switched mode arbitrary excitation using Harmonic Reduction Pulse Width Modulation (HRPWM) in array imaging applications

2016 IEEE International Ultrasonics Symposium (IUS)

Carpenter

Smith

et al. 2016

Abstract-Switched excitation allows the miniaturisation of excitation circuitry for transducer integrated front ends, high channel count and portable ultrasound systems. Harmonic Reduction Pulse Width Modulation (HRPWM) provides a method to design five level switched mode excitation signals with control of instantaneous amplitude, frequency and phase plus minimised third harmonics for advanced ultrasound applications. This paper details the application of HRPWM using commercial transmit front end integrated circuits and linear array transducers. The ability of HRPWM to control the pressure of the ultrasound wave is investigated. A full scale error between desired and measured pressure of 3.5% at 4.1 MHz is demonstrated. The temporal windowing of linear frequency modulated excitation signals using HRPWM is demonstrated. Pulse compression linear imaging of a tissue phantom is demonstrated where an improvement in the -20 dB axial resolution of a nylon mono-filament target from 2.14 mm using bipolar excitation to 1.88 mm using HRPWM is shown.