A high performance board for acquisition of 64-channel ultrasound RF data E. Boni, A. Cellai, A. Ramalli and P. Tortoli Electronics & Telecommunications Dept, University of Florence, Italy piero.tortoli@unifi.it Abstract— The experimental test of new advanced ultrasound techniques frequently requires the acquisition of raw radiofrequency (RF) data from the individual elements of an array probe. The throughput rate and the total amount of these “pre-beamforming” data can be so high that only the most advanced research platforms are equipped to perform such acquisition, but may have difficulties to extend it over suitably long time intervals. In this paper, we report on the development of a high capacity (up to 36 GB) memory board which can be installed inside the Ultrasound Advanced Open Platform (ULA- OP). 64 channel raw RF data can be acquired without interfering with the programmed real-time operation modalities of the system. Examples of application are discussed. Keywords: Open Ultrasound platform; Ultrasound research systems; Raw data acquisition; ULA-OP. I. INTRODUCTION The experimental test of innovative advanced ultrasound (US) techniques, like synthetic aperture imaging [1], Fourier imaging [2] and adaptive beamforming [3-4], frequently requires the acquisition of huge amounts of radiofrequency (RF) echo-data. Especially when this need involves the individual elements of an array probe (“pre-beamforming” data), the corresponding throughput rate can be very high and the total data amount can result prohibitively large. For example, considering a system with 64 active channels, each one sampling the echo-signals at 50 MHz with 12-bit Analog to Digital Converters (ADCs), the overall rate during the receiving phase would be 38.4 Gbit/s. Moreover, running the system at 10 kHz pulse repetition frequency (PRF), the collection of 2048 samples per probe element in each pulse repetition interval (PRI) yields 19.7 GB of memory to cover 10 seconds of acquisition. Neither the commercial scanners nor most research platforms are typically equipped with an acquisition system capable of such performance. In the systems where raw data from the individual array elements can be stored, the acquisition cannot usually extend over suitably long time intervals. The DiPhAS (Fraunhofer Institute for Biomedical Engineering IBMT, Ingbert, Germany) provides 4 GB internal memory to acquire 16-bit samples @40MHz from up to 256 channels [5]. This means that, e.g., 16 MB can be allocated to each channel when the number of channels is limited to 64. Ultrasonix (Richmond, BC, Canada) developed a 16 GB external data acquisition system which can be interfaced with their systems through the probe connector. This system allows acquiring 12-bit samples @40MHz or 10-bit samples @80MHz from 128 independent channels [6]. Finally the SARUS scanner, developed by Jensen’s group [7], can acquire 128 GB from 1024 channels sampled at 12-bit@70MHz. Even the total amount of memory of the listed systems looks impressive, the available memory per channel is equal to 128 MB. The ULtrasound Advanced Open Platform (ULA-OP) [8], developed in our laboratory, can dedicate up to 1GB of internal DDR memory to the acquisition of pre-beamforming data. This small amount of memory (16 MB per channel) usually allows saving no more than 1 second of data, depending on the PRF and on the number of samples saved for each PRI. In this paper, we report on the development of a high capacity memory board which can be installed inside the ULA-OP. The raw RF echo-data collected by 64 probe elements can be acquired without interfering with the real-time operation of the system. After a brief description of ULA-OP and of the new acquisition board, an example of application to plane wave imaging is reported. II. ACQUISITION SYSTEM A. ULA-OP architecture The ULA-OP is a portable system integrated in a metal rack and connected to a PC where a dedicated software runs. The backplane hosts the probe connector and routes the signals among 2 main boards: an analog board (AB) and a digital board (DB). The AB includes the RF front-end (transmitters, multiplexers and low-noise receivers) while the DB hosts the digital devices in charge of numerical beamforming and signal/image processing. An expansion connector is also available on the backplane to connect optional boards like the one discussed in this paper. This research was partly supported by the European Union’s Seventh FrameworkProgramme (FP7/2007-2013) for the Innovative Medicine Initiative under grant agreement number IMI/115006 (the SUMMIT consortium). 2067 978-1-4673-4562-0/12/$31.00 ©2012 IEEE 2012 IEEE International Ultrasonics Symposium Proceedings 10.1109/ULTSYM.2012.0517