Ultrasound array transmitter architecture with high timing resolution using embedded phase-locked loops

Abstract

Abstract-Coarse time quantization of delay profiles within ultrasound array systems can produce undesirable sidelobes in the radiated beam profile. The severity of these sidelobes is dependent upon the magnitude of phase quantization error -the deviation from ideal delay profiles to the achievable quantized case. This paper describes a method to improve inter channel delay accuracy without increasing system clock frequency by utilising embedded Phase-Locked Loop (PLL) components within commercial Field Programmable Gate Arrays (FPGAs). Precise delays are achieved by shifting the relative phases of embedded PLL output clocks in 208 ps steps. The described architecture can achieve the necessary inter element timing resolution required for driving ultrasound arrays up to 50 MHz. The applicability of the proposed method at higher frequencies is demonstrated by means of extrapolating experimental results obtained using a 5 MHz array transducer. Results indicate an increase in Transmit Dynamic Range (TDR) when using accurate delay profiles generated by the embedded PLL method described, as opposed to using delay profiles quantized to the system clock.

Increasing the sonoporation efficiency of targeted polydisperse microbubble populations using chirp excitation

“…1), which was based on the Ultrasound Array Research Platform architecture reported previously [57]. The system is capable of driving transducer loads with excitation signal amplitudes up to ±100 V using a commercially available integrated circuit (MAX4811, Maxim Integrated, San Jose CA, USA).…”

Enhancement of contrast and resolution of B-mode plane wave imaging (PWI) with non-linear filtered delay multiply and sum (FDMAS) beamforming

“…In order to study the effectiveness of FDMAS beamforming technique on PWI and CPWI, several laboratory experiments have been carried out on wire and multipurpose phantom with UARP II [4] [5]. Our first experiment was carried out on 120µm wire phantom located from 20 mm until 60 mm depth with 10 mm spacing between them as shown in Fig.…”

Selecting the number and values of the CPWI steering angles and the effect of that on imaging quality

“…A 128-element L3-8/40EP medical probe with 0.3048 mm centre-to-centre distance was used during the experiments, driven by the Ultrasonic Array Research Platform (UARP) developed by the ultrasound group [14]- [16]. The UARP provides the control for 96 channels.…”