1,237 research outputs found
A Modular Testbed for Hardware Reconfigurable Radio at the 2.4 GHz ISM Band
No full textA modular testbed for use in developing software defined radio is documented in this paper. The testbed is focused on the 2.4 GHz ISM band but may be used at other frequencies. An RF transceiver with variable transmit/receive frequencies and bandwidths is provided.
It provides the capability to support many modulation schemes and standards such as GSM, UMTS< IEEE 802.11b and parts of the IEEE802.16 standards. It performs the RF functions of the radio, with the other PHY and MAC layer functions such as equalisation and error-coding being performed by a host computer. It communicates with the host computer system through a USB2 interface allowing data rates of up-to 60Mbytes a second. An API is used for communications with the host computer system allowing for modulation/demodulation and coding/decoding in software on the host system and reconfiguration of the radio syste
Handwritten Dedication to Jeremiah Farrell from Marc Romano, author of Crossworld
No full textA handwritten note of appreciation sent to Jeremiah Farrell by Marc Romano, the author of Crossworld: One Man\u27s Journey into America\u27s Crossword Obsession . Farrell was the renown creator of the 1996 Election Day Puzzle that predicted the election by allowing for Clinton or Bobdole to be valid responses. Romano mentions the puzzle several times in his own work and corresponded with Farrell regarding his book and the best puzzle in the world .https://digitalcommons.butler.edu/faculty_images/1001/thumbnail.jp
Performance requirements for analog-to-digital converters in wideband reconfigurable radios
No full textWith the current trend towards software defined radio, several dandidate architectures for the analog receiver front-end have been presented. A common proposal for software defined reconfigurable radio is to develop a wideband ADC and utilise this for capturing a large segment of the spectrum. This would enable the subsequent signal processing operations of channel selection and data extraction to be carried out by a digital processor. This would allow the radio to be reconfigured by simply changing the software.
In analysis of these systems, powerful neighbouring signals, or blockers, are considered but it has been conveniently assumed that suitable dynamic range will be available at the ADC. THis is an acceptable assumption in narrowband systems where automatic gain control and analogue channel select filters can be used, but is not appropriate for a wideband system. In this paper we present an analysis based on bit-error-rates (BER) which shows the effect of blockers in a wideband architecture on the performance of the communication link and on the dynamic range requirements of the ADC.
We consider, as a representative example of a real world situation, the use of a wideband receiver on a Rayleigh fading channel. In any analysis of wideband receivers, the behaviour of the channel must also be included as the performance of the communication link is a combination of noise sources from both the channel and the electronics. The effect of high power interferers and blockers on the quantisation noise from the ADC will be mathematically modelled and the BER rates for the communication system will be presented. Given these results, it is possible to determine the minimum required resolution and dynamic range for an ADC in a wideband system given the spectral environment at the frequencies of interest
Modelling and Design of High-Order Phase Locked Loops
No full textIn this paper a new stable high order Digital Phase Lock Loop (DPLL) design technique is proposed. This technique uses linear theory to design the DPLL. The stability of the DPLL is guaranteed by placing a restriction on the system gain. This stability boundary is found by transforming the system transfer function to the Z-domain and plotting the root locus of the LPLL for values of gain where all the system poles lie inside the unit circle. The max value of gain where all the poles lie inside the unit circle is the stability boundary. It is shown that the stability boundary of the LPLL is comparable to the stability boundary of the
DPLL. Finally where the above Bessel filter system produces slow lock, gear shifting of the DPLL components is considered. This allows the DPLL to start off with a wide loop bandwidth and switch to the narrow bandwidth once the system has locked
Jeremiah Farrell with Dennis Sasha, author of Puzzling Adventures: Tales of Strategy, Logic and Mathematical Skill
No full textJeremiah Farrell is awarded the title of Omniheurist, First-Class for solving the eloborate embedded puzzle in Dennis Sasha\u27s book, Puzzling Adventures . The cryptic puzzle required Dr. Farrell to travel to New York City on a certain day to meet two persons in yellow with one wearing a red wig. The event was featured in articles in Indy Star and the New York Sun.https://digitalcommons.butler.edu/faculty_images/1003/thumbnail.jp
R.C. Farrell Store
No full textPhotograph - People standing in front of R.C. Farrell, General Merchant store, Athabasca, Alberta. Left to right: Lance Smith, Louis Menard, Romeo Farrell, Athela LaRue Farrell, and Ray Vari
Farrell and Daigneau Store
No full textPhotograph - Interior view of Farrell and Daigneau Store, Athabasca, Alberta. Left to right, Hamel (book keeper), Joseph Arthur Daigneau, Jim Demers, Moise Hogne, and Romeo C. Farrel
Economist and author Chris Farrell to speak on campus
No full textAn award winning journalist, Farrell is a regular contributor to American Public Media\u27s Marketplace Morning Report
Machine Translation Markers in Post-Edited Machine Translation Output
No full textThe author has conducted an experiment for two consecutive years with postgraduate university students in which half do an unaided human translation (HT) and the other half post-edit machine translation output (PEMT). Comparison of the texts produced shows - rather unsurprisingly - that post-editors faced with an acceptable solution tend not to edit it, even when often more than 60% of translators tackling the same text prefer an array of other different solutions. As a consequence, certain turns of phrase, expressions and choices of words occur with greater frequency in PEMT than in HT, making it theoretically possible to design tests to tell them apart. To verify this, the author successfully carried out one such test on a small group of professional translators. This implies that PEMT may lack the variety and inventiveness of HT, and consequently may not actually reach the same standard. It is evident that the additional post-editing effort required to eliminate what are effectively MT markers is likely to nullify a great deal, if not all, of the time and cost-saving advantages of PEMT. However, the author argues that failure to eradicate these markers may eventually lead to lexical impoverishment of the target language
Campus to host guest speaker Jim Farrell during Earth Week 2011
No full textFarrell is an author, professor, and frequent speaker on “greening” college campuses
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