Use of modulated excitation signals in medical ultrasound. Part I: basic concepts and expected benefits

Misaridis, T.; Jensen, Jørgen Arendt

doi:10.1109/tuffc.2005.1406545

Cited by 343 publications

(243 citation statements)

References 34 publications

Supporting

Mentioning

227

Contrasting

Unclassified

Order By: Relevance

“…This can be avoided by transmitting a coded pulse, such as a frequency-modulated chirp pulse, and performing a matched filter on receive, compressing the received pulse into the autocorrelation function of the transmitted waveform. This allows a long pulse to be transmitted with more energy without sacrificing axial resolution [25][26][27].…”

Section: Pulse Compression Imagingmentioning

confidence: 99%

Medical ultrasound systems

Powers

Kremkau

2011

Interface Focus.

View full text Add to dashboard Cite

Medical ultrasound imaging has advanced dramatically since its introduction only a few decades ago. This paper provides a short historical background, and then briefly describes many of the system features and concepts required in a modern commercial ultrasound system. The topics addressed include array beam formation, steering and focusing; array and matrix transducers; echo image formation; tissue harmonic imaging; speckle reduction through frequency and spatial compounding, and image processing; tissue aberration; Doppler flow detection; and system architectures. It then describes some of the more practical aspects of ultrasound system design necessary to be taken into account for today's marketplace. It finally discusses the recent explosion of portable and handheld devices and their potential to expand the clinical footprint of ultrasound into regions of the world where medical care is practically non-existent. Throughout the article reference is made to ways in which ultrasound imaging has benefited from advances in the commercial electronics industry. It is meant to be an overview of the field as an introduction to other more detailed papers in this special issue.

show abstract

Section: Pulse Compression Imagingmentioning

confidence: 99%

Medical ultrasound systems

Powers

Kremkau

2011

Interface Focus.

View full text Add to dashboard Cite

show abstract

“…Windowing the signal in the time domain reduces sidelobes in the filtered response and increases dynamic range [8]. A theoretical analysis of a wide range of appropriate window functions can be found in [13].…”

Section: Lfm Excitationmentioning

confidence: 99%

“…A popular choice of coded excitation for ultrasound are Linear Frequency Modulated (LFM) signals [8]. LFM signals can be generated using multi-level switched excitation circuits as demonstrated previously [9].…”

Section: Introductionmentioning

confidence: 99%

Harmonic cancellation in switched mode Linear Frequency Modulated (LFM) excitation of ultrasound arrays

Cowell¹,

Smith²,

Freear³

2011

2011 IEEE International Ultrasonics Symposium

View full text Add to dashboard Cite

Abstract-Switched excitation is a convenient alternative to high frequency linear power amplifiers for multi-channel array systems. Unfortunately, switched mode excitation signals often contain harmonics that are undesirable in applications such as coded harmonic imaging. Harmonics can be reduced in switched excitation with the addition of intermediary voltage levels and careful control of switching timing. This work discusses two, three, five and nine level switched mode excitations suitable for Linear Frequency Modulated (LFM) coded excitation. Simulations in MATLAB compare two LFM signals with a central frequency 0.5 MHz, duration of 100 µ µ µs and bandwidths of 25% and 100% to an ideal 'analogue' case. Simulated results shows harmonic cancellation in the switched mode signals. For the nine level case, all harmonics below the 11th are cancelled. Experimental measurements are also obtained using the UARP system loaded with a 0.5 MHz transducer. Experimental results show cancellation of harmonics to −40 dB below the fundamental, however an increase in the third harmonic is apparent when comparing nine levels to five levels. To further verify harmonic reduction, calculations of the Total Harmonic Distortion are provided for each switched mode excitation up to the ninth harmonic.

show abstract

“…Medical ultrasonic systems have seen widespread interest in pulse compression systems, Misaridis published a comprehensive introduction series to medical pulse compression [6,7,8] whilst other introduction and developers guides have been published [9,10]. Bridging the gap between NDT and medical systems have been papers monitoring bone thickness and density [11,12].…”

Section: Insert Figure 2 Herementioning

confidence: 99%

Quinary excitation method for pulse compression ultrasound measurements

Cowell

Freear

2008

Ultrasonics

View full text Add to dashboard Cite

A novel switched excitation method for linear frequency modulated excitation of ultrasonic transducers in pulse compression systems is presented that is simple to realise, yet provides reduced signal sidelobes at the output of the matched filter shows improvements in signal to sidelobe noise power in the order of 7 to 8 dB.The reported quinary switched method for linear frequency modulated excitation provides improved performance compared to pesudo chirp excitation without the need for high performance excitation amplifiers.

show abstract

Use of modulated excitation signals in medical ultrasound. Part I: basic concepts and expected benefits

Cited by 343 publications

References 34 publications

Medical ultrasound systems

Medical ultrasound systems

Harmonic cancellation in switched mode Linear Frequency Modulated (LFM) excitation of ultrasound arrays

Quinary excitation method for pulse compression ultrasound measurements

Contact Info

Product

Resources

About