Search results for "Discrete frequency domain"
showing 4 items of 4 documents
UWB Channel Measurements for Hand-Portable Devices: A Comparative Study
2007
On-body UWB signal propagation is analyzed using two different types of UWB antennas. For the study, measurements of the frequency response by means of a VNA (vector network analyzer) are performed at 2001 discrete frequency points in the 3 to 6 GHz range. Separated measures are taken for four different transmitter positions on the head and six receiver positions on the body. Channel estimation parameters, such as mean excess delay, delay spread and path loss are obtained. Results are similar for both types of antennas regarding path loss exponent and average power delay profiles.
UWB Channel Measurements for Measures for Hand-Portable and Wearable Devices
2007
On-body UWB signal propagation is analyzed for propagation channels surrounding the body in an usual office environment for an application requiring the transmission of signals recorded from the head to a device such as a mobile phone or a PDA carried by the subject or also from the transmitter on the head to other devices located along the body. For the study, measurements of the frequency response by means of a VNA (Vector Network Analyzer) are performed at 2001 discrete frequency points in the 3 to 6 GHz range. Channel estimation parameters, such as mean excess delay, delay spread and path loss are obtained. Results show that for the transmitter located on top of the head best average pe…
A Robust Wrap Reduction Algorithm for Fringe Projection Profilometry and Applications in Magnetic Resonance Imaging.
2017
In this paper, we present an effective algorithm to reduce the number of wraps in a 2D phase signal provided as input. The technique is based on an accurate estimate of the fundamental frequency of a 2D complex signal with the phase given by the input, and the removal of a dependent additive term from the phase map. Unlike existing methods based on the discrete Fourier transform (DFT), the frequency is computed by using noise-robust estimates that are not restricted to integer values. Then, to deal with the problem of a non-integer shift in the frequency domain, an equivalent operation is carried out on the original phase signal. This consists of the subtraction of a tilted plane whose slop…
Discrete frequency models for inventory management – an introduction
2001
Abstract The paper deals with the problem of devising a periodic replenishment policy when orders must be periodic, but only a given, discrete set of order frequencies can be used. The multi-item, instantaneous replenishment case with known demand is studied. In particular, staggering policies somehow arranging replenishments not to come at the same time instants are considered. The paper is composed of three parts: first, a taxonomy of several versions of the discrete frequency problem is proposed, according to different elements; in the second part, a general mixed integer programming model is proposed which is able to capture the peculiarities of the whole spectrum of this kind of proble…