Plasma immersion ion implantation applies a series of negative high-voltage pulses to a target immersed in a plasma. An analytical model of the currents and potentials induced before, during, and after the negative bi...
Plasma immersion ion implantation applies a series of negative high-voltage pulses to a target immersed in a plasma. An analytical model of the currents and potentials induced before, during, and after the negative bias in a planar geometry is presented. The effect of multiple pulses on the results is also studied. The model determines the time-varying ion current, electron current, total current, total dose, and sheath thickness for a piecewise linear voltage pulse. The sheath collapse is found to be important for high repetition rate pulses. Implementation of the model is done in SPICE, a circuit simulator. Comparison with experimental data has demonstrated the accuracy of the model.
Using maximum entropy spectral analysis and the theory of the Wold-Cramer evolutionary spectrum we develop the evolutionary maximum entropy (EME) estimator for non-stationary signals. The EME estimation reduces to the...
详细信息
This paper decribes a novel method for detecting nonstationary signals in colored noise. A first order complex autoregressive, or AR(1), signal model is used which restricts the application of the detector to low orde...
详细信息
The known eigendecomposition-based subspace techniques for parameter estimation of multiple signals in additive white noise or the directions of arrivals of wavefronts at an array of sensors use either the information...
As the complexity of a detection algorithm increases, analytic performance evaluation becomes increasingly difficult and is often intractable. In such casts, Monte Carlo simulations can be used, but they often require...
详细信息
Perfect reconstruction (PR) time-varying analysis-synthesis filter banks are those in which the filters are allowed to change from one set of PR filter banks to another as the input signal is being processed. Such sys...
详细信息
An important criterion of any Ground Penetrating Radar is to maximise penetration while maintaining a given resolution. To achieve this, low frequencies must be used for low loss, but high proportional bandwidths are...
详细信息
An important criterion of any Ground Penetrating Radar is to maximise penetration while maintaining a given resolution. To achieve this, low frequencies must be used for low loss, but high proportional bandwidths are then required to maintain high range resolution. A Homodyne Step Frequency Radar is being developed to accommodate these requirements. However the wideband nature of the radar raises problems with I/Q channel errors and mismatches. These errors defocus the correct response by spreading energy across the range profile and introducing an Hermitian image. A well focussed range profile allows maximal sidelobe reduction by windowing. This paper addresses the technique for correcting these effects of common and differential I/Q gain and phase errors by signalprocessing. We present results obtained from a very broadband homodyne radar where a correction process for common I/Q errors allows the ideal sinc response to be recovered in the region of the target response.
We present a solution to the multi-scale deconvolution problem using higher order spectra where the data to be deconvolved consist of noise corrupted sensor array measurements. The model assumes that the data are gene...
详细信息
We present a novel solution to a deconvolution problem in which the data to be deconvolved consist of sensor array measurements. Our model assumes that the data are generated as a convolution of an unknown wavelet wit...
详细信息
Optical flow computation may be divided into four processing steps where the first is extraction of image features suitable for flow estimation. Using a generalization of the basic flow constraint it is possible to es...
详细信息
暂无评论