Subaperture decoding to enhance performance of coded excitation

Takashi Azuma, Yuichi Miwa, Shin Ichiro Umemura

Research output: Contribution to journalConference articlepeer-review

7 Citations (Scopus)

Abstract

Coded excitation requires long code to improve signal to noise ration (SNR). However, in order to achieve a high lateral resolution, the beam forming is normally performed based on a low f-number and realtime dynamic focusing, which limits the maximum length of coded waves. Individual decoding before beamforming can solve this problem, but it demands an enormous size of hardware. In this study, a subaperture decoding technique is proposed to achieve a high SNR based on coded excitation without compromising lateral resolution. In this technique, the receiving aperture is divided into N subapertures, beamforming is performed for each subaperture, and each output is decoded, delayed and summed together to complete beamforming in whole aperture. Computer simulations were used to demonstrate this technique. When the transmission waveform was encoded by the 13-chip Barker code and decoded with a mismatched filter, and the reception f-number was 1, the proposed technique, with the number of subaperture of 16, lowered the range sidelobe level from -25 dB to -45 dB.

Original languageEnglish
Pages (from-to)1669-1672
Number of pages4
JournalProceedings of the IEEE Ultrasonics Symposium
Volume2
Publication statusPublished - 2002 Dec 1
Event2002 IEEE Ultrasonics Symposium - Munich, Germany
Duration: 2002 Oct 82002 Oct 11

ASJC Scopus subject areas

  • Acoustics and Ultrasonics

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