Volume 11 Issue 5
A Novel Encoded Excitation Scheme in a Phased Array for The Improving Data Acquisition Rate
César Gutiérrez-Fernández,Ana Jiménez,Carlos Julián Martín-Arguedas,Jesús Ureña andÁlvaro Hernández
Electronics Department, University of Alcalá, Campus Universitario. Ctra. Madrid-Barcelona Km. 33.600, Madrid 28805, Spain
*Author to whom correspondence should be addressed.
Abstract
One of the challenges of phased array (PA) ultrasonic imaging systems is their limited capability to deal with real-time applications, such as echocardiography and obstetrics. In its most basic outline, these systems require emitting and receiving with the entire array for each image line to be acquired; therefore, with many image lines, a higher acquisition time and a lower frame rate. This constraint requires one to find alternatives to reduce the total number of emissions needed to obtain the whole image. In this work, we propose a new PA scheme based on the Code Division Multiple Access (CDMA) technique, where a different code is assigned to each steering direction, allowing the array to emit in several directions simultaneously. However, the use of encoding techniques produces a reduction of the image contrast because of the interferences between codes. To solve this, a new scheme based on merging several images is proposed, allowing the system to get close to the theoretical maximum frame rate, as well as to limit the loss of contrast, intrinsic to the technique.Keywords:
ultrasound imaging; phased arrays; CDMA (Code Division for Multiple Access); acquisition rate