Cowell, DMJ orcid.org/0000-0003-0854-542X, Carpenter, TM orcid.org/0000-0001-5676-1739, Clegg, HR et al. (2 more authors) (2019) Phase Dithered Modulation in Switched Mode Excitation for Improved Amplitude Control. In: Proceedings of the 2019 IEEE International Ultrasonics Symposium (IUS). 2019 IEEE International Ultrasonics Symposium (IUS), 06-09 Oct 2019, Glasgow, United Kingdom. IEEE , pp. 985-988. ISBN 978-1-7281-4597-6
Abstract
Multi-level switched mode transmitters provide a simplified method of exciting ultrasound transducers compared to linear amplifiers. Excitation waveforms are created which switch between typically 3 or 5 high voltage supplies with high drive current. Previously, Harmonic Reduction Pulse Width Modulation (HRPWM) has shown how control of amplitude and instantaneous frequency or phase can be achieved. Arbitrary excitation can be achieved using Arbitrary Harmonic Reduction Pulse Width Modulation (AHRPWM). However, the synthesis of exact tones frequencies remains problematic, especially where high frequencies, low amplitudes, or integer divisions of the transmitter sampling frequency occur. This paper presents a method of improving the amplitude control of modulated waveforms through the application of phase dithering. The addition of random noise to phase during the calculation of the modulated waveforms has the benefit of disturbing periodicity which occurs where the synthesized frequency is an integer division of the sampling frequency. An experimental investigation demonstrates the improvement of amplitude control from 11% to 3% standard deviation for a 10 MHz switched waveform sampled at 80 MHz.
Metadata
Item Type: | Proceedings Paper |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2019, IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. |
Keywords: | Switches; Acoustics; Frequency modulation; Ultrasonic imaging; Harmonic analysis; Frequency control; Frequency conversion |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Electronic & Electrical Engineering (Leeds) > Robotics, Autonomous Systems & Sensing (Leeds) |
Funding Information: | Funder Grant number EPSRC Not Known EPSRC EP/S001069/1 |
Depositing User: | Symplectic Publications |
Date Deposited: | 05 Feb 2020 12:56 |
Last Modified: | 07 Feb 2020 15:00 |
Status: | Published |
Publisher: | IEEE |
Identification Number: | 10.1109/ultsym.2019.8926298 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:156527 |