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Digital Interpolation in the Passband Domain

This paper presents techniques for digital interpolation in the passband domain, exemplarily for a carrierless amplitude modulation/phase modulation (CAP) transmission system. Well-known techniques for designing baseband interpolation filters are extended to signal processing at nonzero center frequencies. The resulting filters are either real- or complex-valued. Real-valued interpolation filters

Physical limitations on scattering and absorption of antennas

In this paper, physical limitations are presented for antennas of arbitrary shape. Antenna properties such as bandwidth and directivity are shown to be bounded from above by the antenna volume and certain shape coefficients given by the eigenvalues of the high-contrast polarizability dyadic. The theoretical results are illustrated by a resonant loop antenna and an ultrawideband (UWB) spiral antenn

An Analysis of a Modified Point Coordination Function in IEEE 802.11 Wireless LAN

Since the point coordination function (PCF) in the IEEE 802.11 is based on a centralized polling protocol, some bandwidth is wasted due to the polling overheads and also due to packets that are issued in case a polled station does not have any data to transmit. In order to reduce this waste and increase the channel utilization, we have proposed a modified version of the standard PCF. The modified

Cryptanalysis of pomaranch

Pomaranch is a synchronous stream cipher submitted to eSTREAM, the ECRYPT Stream Cipher Project. The cipher is constructed as a cascade clock control sequence generator, which is based on the notion of jump registers. We present an attack which exploits the cipher’s initialisation procedure to recover the 128-bit secret key. The attack requires around 265 computations. An improved version of the a