| viXra.org > Digital Signal Processing > 2412 |
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| viXra.org > Digital Signal Processing > 2412 |
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[2] viXra:2412.0028 [pdf] submitted on 2024-12-06 20:43:01
Authors: Sasan Ardalan
Comments: 37 Pages.
A technique for modeling plane wave propagation through inhomogeneous media and plasma layers with different electron densities is presented. The technique is based on transmission line theory. Therefore, a general technique is introduced for solving complex transmission line systems. A data structure and algorithm for representing, and simultaneously solving for all nodes within the transmission line network is presented. The method is based on representing the network as a recursive tree structure and solving for the voltage, current, and impedance at each node using recursive programming techniques. First, all frequency dependent parameters within the tree structure are updated, then in a post-order traversing of the tree, the impedance at each node are computed followed by a pre-order traversing of the tree to compute node voltagesand currents. For plane wave propagation, the reflection coefficient, the electric field andmagnetic field are computed. The method is applied to normal incidence but can easily be extended to oblique incidence. A tapered transmission line model was used to verify the algorithm. In addition, an example was provided verifying the ability to compute the frequency response and impulse response of a system with a plasma. Finally, the application of the technique to model the heat tile and the plasma that develops on either aero-assist or spacecraft re-entry is presented.This paper is based on work done at the Center for Communication and Signal Processing (CCSP) at North Carolina State University by the author in 1987. In addition, the paper presents work which was supported by NASA Langley Research Center under Contract NASI-1x925. The author was the Principal Investigator.
Category: Digital Signal Processing
[1] viXra:2412.0002 [pdf] submitted on 2024-12-02 02:06:58
Authors: Sasan Ardalan
Comments: 38 Pages.
The up conversion of a 5GHz WiFi signal to 10.56GHz IF signal enables the transmission of the WiFi signal at XBand frequencies for high throughput digital communications over XBand. The XBand signal can be up converted from the 10.56GHz XBand signal to 60 GHz or 28 GHz bands. It is imperative that the WiFi channel be centered at a specific frequency, for example, 10.56GHz, for optimal performance and to meet ITU an FCC band allocation requirements. In addition, the WiFi channel centered at 10.56GHz must be interference (jammer) free so that the over the air signal is jammer free, a key requirement. The XBand Spectrum is also available for Amateur Extra Class from 10.0GHz to 10.5GHz so the capability to center the frequency is critical. This paper describes the challenges in up converting and down converting WiFi signals at 5GHz to X-Band and offers a unique solution that provides a jammer free spectrum and capability to dial in the center frequency. A complete system was designed, prototyped and built, verifying the design over the air. IEEE802.11ac Access Points were used at 5.21 GHz with a bandwidth of 160 MHz. This work paves the way for high throughput digital communication over XBand links with bandwidths of 80MHz and 160MHz.
Category: Digital Signal Processing
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