Improving Performance of Pulse Compression in a Doppler Ultrasound System Using Amplitude Modulated Chirps and Wiener Filtering

Cowe, Joanne; Gittins, John; Evans, David H.

doi:10.1016/j.ultrasmedbio.2007.08.001

Cited by 22 publications

(10 citation statements)

References 9 publications

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“…This holds true when using matched filtering; however, this study uses mismatched filtering to minimise the RSLL and, as a result, the improvement in power will be slightly lower than that given in (2).…”

Section: E Performance Parameters 1) Theoreticalmentioning

confidence: 93%

Coded excitation can provide simultaneous improvements in sensitivity and axial resolution in Doppler ultrasound systems

Cowe

Boni

Ricci

et al. 2010

2010 IEEE International Ultrasonics Symposium

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We investigated the possibility of using coded excitation and pulse compression in Doppler ultrasound systems to improve resolution and signal-to-noise ratio (SNR) without increasing transmitted energy or peak power. A small target simulator was used, together with a programmable real-time ultrasound system which has the facility to generate arbitrary transmit waveforms and to acquire the received RF signal.The study demonstrated that it was possible to achieve an axial resolution of 0.197 mm with sidelobe level of -42.3 dB when using a linearly frequency modulated chirp with 5 μs duration, 8 MHz bandwidth and 8 MHz centre frequency. This can be compared with the 0.217 mm resolution obtained when using a 3-cycle noncoded pulse with 8 MHz centre frequency. On average the SNR was improved by 8.1 dB when using the chirp compared with the non-coded pulse. This improvement was achieved despite the two pulses having approximately the same transmitted energy and the peak amplitude of the coded signal being 47% of the noncoded signal.We conclude that simultaneous improvements in axial resolution and SNR can be made in Doppler ultrasound systems using coded excitation and pulse compression, without increasing the transmitted energy and with a reduction in pulse amplitude, when compared with conventional, non-coded processing.

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Section: E Performance Parameters 1) Theoreticalmentioning

confidence: 93%

Coded excitation can provide simultaneous improvements in sensitivity and axial resolution in Doppler ultrasound systems

Cowe

Boni

Ricci

et al. 2010

2010 IEEE International Ultrasonics Symposium

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show abstract

“…In another study, Cowe et al reported on an amplitude modulation method to improve transcranial doppler [8]. An inverse filter was designed and an amplitude modulation applied to counteract the effect of the transducer for two-way propagation, therefore resulting in a closer match to the original chirp on receive [8].…”

Section: Transducer Compensationmentioning

confidence: 99%

“…An inverse filter was designed and an amplitude modulation applied to counteract the effect of the transducer for two-way propagation, therefore resulting in a closer match to the original chirp on receive [8]. Cowe et al reported improvements in axial resolution as a result of better compression when using the inverse-filtered, amplitude-modulated signals.…”

Section: Transducer Compensationmentioning

confidence: 99%

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Pre-distorted amplitude modulated (PDAM) chirps for transducer compensation in harmonic imaging

Smith

Harput

Cowell

et al. 2012

2012 IEEE International Ultrasonics Symposium

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A pre-distortion by amplitude modulate (PDAM) method is evaluated for use in linear frequency modulated (LFM) coded harmonic imaging. LFM coded signals are known to boost the SNR of the low amplitude harmonics, but due to the nature of harmonic imaging, are located at inefficient regions of the transducer's bandwidth. As a consequence, the LFM signal is subjected to transducer-induced tapering which is particularly severe at the start or end of the signal. The motivation for this work is to investigate whether compensating for this tapering effect results in improved compression of the harmonic signal.PDAM signals are designed using an inverse filter method. Hydrophone measurements show successful transducer compensation of the fundamental signal. Fundamental and second harmonic images of a tissue mimicking phantom indicate minimal improvement when compared with non pre-distorted LFM signals (N-PDAM). A discussion is provided as to why this result can be attributed to the use of a sub-optimal compression filter.

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“…It has been studied and applied to medical ultrasound for almost 10 years [6][7][8][9][10][11][12][13][14]. A variety of coded excitations have been developed, including the linear frequency modulated (LFM) signal or nonlinear frequency modulated signal [6][7][8], and the phase coded signal, such as Barker codes [9,10], m-sequences [11] and Golay complementary sequences [12], and the amplitude modulated signal [13,14]. They can be basically categorized according to their modulation functions into three types: frequency modulation, phase modulation and amplitude modulation.…”

Section: Introductionmentioning

confidence: 99%

Barker coded excitation with linear frequency modulated carrier for ultrasonic imaging

Fu¹,

Wang²,

Huang³

et al. 2014

Biomedical Signal Processing and Control

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Improving Performance of Pulse Compression in a Doppler Ultrasound System Using Amplitude Modulated Chirps and Wiener Filtering

Cited by 22 publications

References 9 publications

Coded excitation can provide simultaneous improvements in sensitivity and axial resolution in Doppler ultrasound systems

Coded excitation can provide simultaneous improvements in sensitivity and axial resolution in Doppler ultrasound systems

Pre-distorted amplitude modulated (PDAM) chirps for transducer compensation in harmonic imaging

Barker coded excitation with linear frequency modulated carrier for ultrasonic imaging

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