If a signal on clock tree is slower than expected due to either a design error or a manufacturing defect, it may cause complicated fault behaviors during scan-based testing. It makes the diagnosis of such defect especially difficult if the defective clock signal is used for both shift and capture operations during the scan testing, because (1) the defect induces hold time faults on scan chains during shift cycles, and (2) hold-time faults may also be introduced during capture cycles in the functional logic paths. In this paper we illustrate the failure behaviors of such clock defects and propose an algorithm to diagnose it.
To locate the imaging slice, the hydrogen protons within the selected slice are excited by the coaction of radio-frequency pulse (RF pulse) and slice-selection gradient during the process of magnetic resonance imaging (MRI). However, the absolute consistency of the time between the RF transmitting system and gradient system can’t be guaranteed in an actual magnetic resonance system, which makes the slice profile not ideal enough. Imperfect slice profile will lead to poor imaging quality. In this paper, Shinnar-Le Roux (SLR) theory is used to simulate the slice profile with different relative delays between RF and slice-selection gradient to solve this problem. By matching the actual slice profile with the simulation results, the relative delay is measured in an actual 0.35T permanent magnet MRI system. The practicability of the method is verified for the improvement of image quality after applying the measured delay to correct the actual MRI system.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.