In commercial ultrasound systems, the transmit module typically generates the time delayed excitation pulses to steer and focus the acoustic beam. However, the ultrasound transmitter module in these systems has limited access to medical ultrasound researchers. In this paper, we have presented the development of a programmable architecture for 8-channel ultrasound transmitter for medical ultrasound research activities. The proposed architecture consists of 8 transmit channels and Field Programmable Gate Array (FPGA) based configurable delay profile to steer acoustic beam, transmit frequency and pulse pattern length depending on the medical application. Our system operates in pulse-echo mode, with ultrasound transmit frequency up to 20 MHz, excitation voltage up to 100 Vpp, and individual channel control with single high speed Serial Peripheral Interface (SPI). Pre-calculated delay profiles per scanline are generated in Matlab, based on physical parameters of 8 element linear transducer array which are used to steer and focus the ultrasound beam. An experiment is carried with our transmit module to transmit ultrasound into gelatin phantom, acquired echoes and processed for B-mode imaging. The results show that this transmit platform can be used for ultrasound imaging researches and also for medical diagnosis.
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