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Hu, Yalin

Publications and source records attributed to Hu, Yalin.

12 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2017

D-DMTD: Digital Dual Mixer Time Difference

The digital design discussed in the following document is inspired by the digital dual mixer time difference circuit and based on the white paper, Digital femtosecond time difference circuit for CERN's timing system. DMTD is originally an analog technique that measures the time difference between two events with high precision using a commercial time interval counter. Our project applies this analog concept to a digital system programmed onto a Microsemi ProASIC3E FPGA (Field- Programmable Gate Array). D-DMTD is a digital system theoretically capable of measuring the time difference between two digital clock signals with very fine resolution (sub-picosecond) using a relatively low frequency counter. The system essentially acts as a digital phase detector with femtosecond time resolution. The main concern with this processing technique is its feasibility and accuracy when implemented on an FPGA. Another concern is the environmentally-induced, horizontal phase noise in the digital signals; this 'litter" jeopardizes the fidelity of the clocks and generates glitches in the signals. Thus, the majority of the work was focused on determining under what conditions the digital design performs optimally and generates the most accurate estimations for the phase shift.

42 ENGINEERING↗
DOE OSTI2012

Exploring formal verification methodology for FPGA-based digital systems

With the Life Extension Programs (LEPs), many nuclear weapon (NW) analog electronic components are being replaced by modern digital devices, increasing system complexities dramatically. Ensuring the reliability, security, and robustness of these upgraded systems is critically important. Many custom hardware systems throughout the NW operations space rely on Field-Programmable Gate Arrays (FPGAs) to implement sophisticated logic. Effective verification, while increasing confidence, can reduce the overall effort in system debugging and testing.

Hu, Yalin↗