Journal article
Compact FPGA-based beamformer using oversampled 1-bit A/D converters
A compact medical ultrasound beamformer architecture that uses oversampled 1-bit analog-to-digital (A/D) converters is presented. Sparse sample processing is used, as the echo signal for the image lines is reconstructed in 512 equidistant focal points along the line through its in-phase and quadrature components.
That information is sufficient for presenting a B-mode image and creating a color flow map. The high sampling rate provides the necessary delay resolution for the focusing. The low channel data width (1-bit) makes it possible to construct a compact beamformer logic. The signal reconstruction is done using finite impulse response (FIR) filters, applied on selected bit sequences of the delta-sigma modulator output stream.
The approach allows for a multichannel beamformer to fit in a single field programmable gate array (FPGA) device. A 32-channel beamformer is estimated to occupy 50% of the available logic resources in a commercially available midrange FPGA, and to be able to operate at 129 MHz. Simulation of the architecture at 140 MHz provides images with a dynamic range approaching 60 dB for an excitation frequency of 3 MHz.
Language: | English |
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Publisher: | IEEE |
Year: | 2005 |
Pages: | 870-880 |
ISSN: | 15258955 and 08853010 |
Types: | Journal article |
DOI: | 10.1109/TUFFC.2005.1503973 |
ORCIDs: | Tomov, Borislav Gueorguiev and Jensen, Jørgen Arendt |
1 bit 140 MHz 3 MHz 32-channel beamformer 60 dB Analog-Digital Conversion Analog-digital conversion B-mode image Biomedical imaging Electronics, Medical Equipment Design Equipment Failure Analysis Field programmable gate arrays Finite impulse response filter Image Enhancement Image Interpretation, Computer-Assisted Image reconstruction Image sampling Logic devices Microcomputers Miniaturization Phantoms, Imaging Sample Size Signal Processing, Computer-Assisted Signal processing Signal sampling Ultrasonic imaging Ultrasonography analog-to-digital converters biomedical ultrasonics color flow map compact FPGA-based beamformer compact beamformer logic delay resolution delta-sigma modulator output stream echo echo signal equidistant focal points excitation frequency field programmable gate arrays finite impulse response filters focusing logic resources low channel data width medical ultrasound beamformer multichannel beamformer quadrature components sampling rate sigma-delta modulation signal reconstruction single field programmable gate array ultrasonic devices