Experimental and theoretical work has been carried out to study the longitudinal space-charge effects in a retarding field energy analyzer. A one-dimensional model for both a mono-energetic beam and a thermal beam has been developed for this purpose. The study shows that, if the current density inside the device were higher than a critical value, the longitudinal space-charge effects would dist...

Using the field-programmable gate array (FPGA) with embedded software-core processor and/or digital signal processor cores, we are able to construct a hardware kernel for measurement instruments, which can fit common electronic measurement and test requirements. We call this approach the software-defined instrumentation (SDI). By properly configuring, we have used the hardware kernel to impleme...

We propose a newly configured optical correlation-domain reflectometry (OCDR) without the use of an electrical spectrum analyzer (ESA) for high-speed distributed reflectivity measurement with enhanced spatial resolution. First, operation ESA-free OCDR is analyzed by numerical simulation, results which show potential configuration to perform improved Subsequently, simulation are verified compari...

In the past quarterly period, the heuristic expression for rms interference given in the Progress Report, April 15, 1949 was considered in more detail. A rigorous justification was found for this expression and also for a simpler, allied problem. The allied problem is the computation of the power spectrum of a transmitter with sinusoidal frequency modulation. When the problem is handled in a co...