Search results for "Prototype filter"
showing 6 items of 6 documents
Subband image coding using filter banks with non-uniform passband distribution
2002
Subband filter banks with non-uniform passband distribution in frequency domain are studied. Several design examples are presented and compared with conventional uniform bandwidth filter banks. Image coding results show that filter banks with non-uniform bandwidth outperform filter banks with uniform bandwidth, especially in low bit rate coding.
Investigation of Multipaction Phenomena in Passive Waveguide Filters for Space Applications
2006
This paper presents an investigation on multipaction risk in microwave bandpass filters. The study reveals higher multipaction risk for narrower bandpass filters. To alleviate the problem with multi-paction generation, different novel filtering structures are proposed. Results demonstrate that using the new structures multipaction risk can be reduced as much as 30% with regard to the initial design.
LabVIEW modeling and simulation, of the digital filters
2015
In order to study digital filters using virtual instrumentation a simulation program specifically designed for this purpose has been developed. To implement this program means to use the following facilities: studying digital Butterworth filters, Cebyshev, Bessel and Median and change their parameters: bandwidth, order, rank and slope; possibility of changing the input parameters: amplitude, offset and frequency; overlay over the input signal, to one of the types of noise such as white noise, Gaussian white noise and Poisson noise; choosing a type of digital filters: low pass, high pass, band-pass and band stop; waveforms graphical representation of the input and output signals; graphical r…
Surface investigation and aluminum oxide estimation on test filters for the ATHENA X-IFU and WFI detectors
2016
The ATHENA mission provides the demanded capabilities to address the ESA science theme "Hot and Energetic Universe". Two complementary instruments are foreseen: the X-IFU (X-ray Integral Field Unit) and WFI (Wide Field Imager). Both the instruments require filters to avoid that the IR radiation heats the X-IFU cryogenic detector and to protect the WFI detector from UV photons. Previous experience on XMM filters recommends to employ bilayer membrane consisting of aluminum deposited on polyimide. In this work, we use the X-ray Photoelectron Spectroscopy (XPS) to quantify the native aluminum oxide thickness that affects the spectral properties of the filter. The estimation of the oxide thickne…
LabVIEW modeling and simulation, of the low-pass and high-pass analog filters
2015
Some programs for simulating different types of filters are developed using LabView software. Implementing a simulation program of an analog filter requires the prior establishment of mathematical model. As a general purpose programming environment, LabVIEW offers possibility of achieving some user programs for plotting frequency characteristics of passive and active analog filters, if established beforehand mathematical models that characterize their behavior. The scientific objectives of this paper are: -the analysis of the possibilities of using virtual instrumentation in the study of electrical filters; -implementation of virtual instruments for analysis and simulation of analog filters…
Novel Narrow-Band Spectral Interference Filter with Very High Transmittance
2011
We report a novel scheme to improve the effective transmission of a standard interference filter, and demonstrate over 97% passband transmission. Such high efficiency is critical for quantum information applications, e.g. high-efficiency single-photon generation utilizing parametric down-conversion. The scheme can also be modified to function with a tilted filter, thereby allowing tuning of the passband frequency. In addition, the tilted configuration creates an infinite number of consecutive reflections from and transmissions through the filter, further improving the net filter transmission. Because spectral interference filters are a key element in optical quantum information experiments …