M.Ing. / The transmission of digital data at higher data rates and greater reliabilities is becoming increasingly more important in the society of today. The usage of, especially wireless digital data, is increasing at an alarming rate, and the need arises for more bandwidth to be made available for this purpose. Hence, the need arises to optimise and expand the usage of bandwidth currently under use. Existing wireless channels, such as the commercial FM service, need to be re-evaluated and unused bandwidth needs to be developed and used as close to capacity as possible. In this dissertation, a study was launched to develop the FM SST (Supplementary Signal Transmission) commercial analog service as a simplex digital channel that can commercially be used to transmit a myriad of digital data. With the help of a commercial FM radio channel, digital data was transmitted using a number of different modulation schemes to obtain channel measurements for the FM SST channel. The modulation scheme that performed the best, given certain criteria, was GMSK. This raw information was then used to extract first and higher order statistical information from the channel, in order to parameterise discrete channel models, based on a Markov process. The channel models that were used were the Gilbert, GilbertElliott and Fritchman channel models. These channel models were then tested according to their iirst and higher order statistical data to evaluate their effectiveness in modelling the error process on the FM SST channel. It was found that the channel model best approximating the real channels was the Gilbert channel. Once satisfactory results were obtained, these discrete channel models were then used to evaluate various error correction schemes for their ability to correct burst errors on the FM SST channel. From the various schemes evaluated, a (63,39) BCH with an interleaver of index 4 was found to perform the best. The purpose of which is to transmit digital data at the highest data rate possible and at the same time having a bit error rate less than lxl0-6.

In identifying the importance of early identification of hearing loss in children, very little attention has been given to how advanced FM technology may improve outcomes. Distance, noise and reverberation remain considerable challenges for individuals using hearing aids, more so in really young children. The aim of this present research was to evaluate and explore the benefits of advanced integrated FM amplification technology with pre-school hearing aided children. The research was of a longitudinal prospective design, including both quantitative and qualitative analysis of FM technology use in pre-school hearing aided participants. All participants were provided with the latest hearing aid and integrated FM amplification technology suited to their hearing loss. An initial study was conducted to validate the 'AutoConnect' feature on the FM technology provided to participants. The manufacturers of the 'AutoConnect' purport the feature removes the need for verifying FM technology 'transparency'. The results indicated the feature did work with the hearing aid and FM combinations used in this study. Three further studies were conducted. The first of these evaluated FM device use via daily diaries, datalogging and questionnaires. Five of the seven families were able to establish regular FM use in a range of environments and settings. The environments where the FM was used most frequently were the home, car, nursery, shopping and outdoors. Listening evaluation measures with FM technology demonstrated the greatest improvements were in noise and at distance. Parents rated the FM technology highly, with all parents reporting 5 out of 5 for 'easy to operate'. Significant improvements in language development were noticed for the three children whose language development was identified as 'at risk' at the start of the study. The second of the three studies qualitatively explored the views and experiences of parents and carers on their use of FM technology. Eight weekly diaries, seven completed by parents and one completed by pre-school nursery staff of one of the participants, were collected throughout the study period. Seven semi structured interviews were conducted with parents at the end of study participation. Altogether eight cases were included for analysis with seven including both diaries and interviews and one case including diary only. Thematic content analysis sought to acknowledge parents and carers as the experts and place them in the centre of knowledge generation. Six main themes were identified: access to speech, listening, communication, wellbeing, engagement/ownership and practicalities of FM use. More detailed sub-themes were generated under the main six headings. Overall the analysis highlighted the potential benefits, barriers and challenges to pre-school use of FM technology. The final study used the language environment analysis (LENA) system to compare differences in language environment with and without FM use. The findings indicated the language environment of the children in this study was comparable to their hearing peers. The acoustic environment results suggested the largest portion of children's day was spent in environments where speech was at a distance or in background noise. The thesis concludes by discussing the findings and implications of this study and highlighting areas for future research. The current study provides a unique contribution to the existing literature and together with future research can be integral to the provision of FM technology as standard for pre-school hearing aided children.

Swedish Armed Forces are according to their development planning process taking actions to establish a new joint unit (SWEWOSE), with electronic warfare capability. SWEWOSÉ S main task will be designated to produce electronic warfare libraries for electronic warfare systems within the armed forces. The unit shall have capability to support with libraries in any state of conflict situation even if the supported unit with library needs conducting operations abroad. This essay examines the requirements that justify the establishment of a new unit in times when the armed forces conducting reorganizations and cutbacks in both economy and personnel. The possibilities to buy complete system solutions from an external supplier are examined. But also what kind of library support model that is to prefer according to the demands that the Swedish Armed Forces desired, in terms of capability in platform protection and battle space awareness. The results show that the demands that the Swedish Armed Forces has decided, best will be ful-filled and justified by a national electronic warfare unit, with library production as a main task.

This master thesis presents the design and implementation of a super heterodyne 5.8 GHz receiver system for wireless transmission of phase alternating line (PAL) composite video signals. The system is implemented using surface and hole mounted devices on four separate printed circuit board (PCB) stages. These stages include a 5.8 GHz radio front-end, a 480 MHz intermediate frequency (IF) stage, a local oscillator (LO) block and frequency demodulation circuit for frequency modulation (FM) signals. Each receiver stage is interconnected using sub-miniature version A (SMA) connectors. The radio front-end PCB consists of a low-noise amplifier (LNA), a 5.8 GHz distributed element pre-select filter and a passive double-balanced mixer. This mixer uses seven discrete injection frequencies at 5260-5380 MHz that are provided by the LO block using a programmable phase-locked loop (PLL) frequency synthesizer device. The IF stage uses an automatic gain control (AGC) feedback loop with a dynamic range of 60 dB. This AGC loop is implemented using a directional coupler, a detector device, a tuning circuit and a variable gain amplifier/attenuator (VGA). The IF at 480 MHz is selected with a 25 MHz surface acoustic wave (SAW) filter. The IF is demodulated to a PAL composite video format using a PLL FM discriminator device intended for direct-broadcast satellite (DBS) signals. This device is fitted to a separate demodulation stage in conjunction with a picture adjustment circuit and a FM de-emphasis network. The output of the demodulator stage is a 75 Ω PAL composite video signal.

The purpose of this study was to investigate the various aspects of low-power frequency modulation educational broadcasting and to formulate from the findings a guide for the establishment of stations on campuses as exemplified at Oklahoma Baptist University. It is hoped that this report will provide detailed information of interest and value to that university, its staff, its present and future scholars, and to other school and individuals interested in building an educational broadcast facility.

Syftet var bland annat att undersöka om försvarsanställda tränar enligt FMFysS på arbetstid, vilka hinder de upplever till träning och hur de övervinner dessa hinder. Bakgrundsvariablerna var kön, anställningsform, ålder samt huruvida träning enligt grundkraven genomförs på arbetstid. Ett egenkonstruerat formulär delades ut vid en av Försvarsmaktens institutioner (n = 286).Den vanligaste orsaken till att inte träna enligt FMFysS på arbetstid var tidsbrist/svårt att planera in träning på arbetstid, det högst rankade hindret till träning var stress/tidbrist och den mest använda strategin för att övervinna hinder till träning var tanken på känslan efteråt. Resultaten diskuteras utifrån tidigare forskning och författaren ger förslag till vad som bör iakttas för att främja uppslutningen kring FMFysS.

The U.S. Army/Marine Corps Counterinsurgency Field Manual (FM 3-24) was published in 2006 and used by the military to consolidate counterinsurgency strategies and tactics and correct the growing military problems in Iraq. However, rather unusually, this military doctrinal publication was also heavily publicized through a wide array of media to the American public giving it an important role in political discourse and the rhetorical history of the U.S. ‘war on terror’. Beyond its military application, the FM 3-24 can be understood as a rhetorical device used by the Bush Administration to repair a collapsing ‘war on terror’ narrative and shore up plummeting public support for the war in Iraq, which had reached its lowest levels at the time of the manual’s publication. Still more important is the language in the text itself, which bears a conspicuous tone of benevolence, historically uncharacteristic to military doctrine. Despite this ‘spirit of goodwill,’ the FM 3-24, in fact, functions as a segment of the ‘war on terror’ narrative and an ideological vehicle for American global hegemony directed primarily toward American audiences. This view is justified by three main trends in the text: One, the manual omits mention of, or minimizes, the moral and political impact of military invasions on foreign countries that necessarily precede counterinsurgency operations; two, it relies fundamentally on legal arrangements with occupied countries that favor American prerogatives; and three, it reduces counterinsurgencies to a simple dichotomy between good and evil, the latter role being assigned to anyone who opposes the United States, which therefore denies the political complexities of that opposition. The FM 3-24 is a prescriptive document that has been 1) designed to militarily extend or reinforce American global power through counterinsurgency operations and 2) used politically to reproduce or justify particular attitudes in the American public that will foster support for those operations.

No description available.

No description available.

The objective of this research is to develop time-varying signal processing methods for rapidly varying non-stationary signals based on time-varying autoregressive (TVAR) modeling, and to apply such methods to frequency-modulated (FM) interference rejection in direct-sequence spread spectrum (DSSS) communications. For fast varying non-stationary signal processing, such as the task to reject an FM interference that could chirp over the entire DSSS bandwidth in a symbol interval, an explicit description of the variation is necessary to form a time-varying filter. This is realized using the TVAR model, which is an autoregressive model whose coefficients are time-varying with the variation modeled as a linear combination of a set of known functions of time. In DSSS communications, when the strength of an interference - which could be a hostile jammer or overlaid communication signal - possibly exceeds the inherent spread spectrum processing gain, interference rejection is necessary to secure a usable bit-error-rate. The contributions of this research include: a) revealed the advantageous performance of TVAR model based instantaneous frequency estimation (TVAR-IF), which is expected to change the prevailing opinion that regards TVAR-IF as a poor estimator; b) proposed a time-varying Prony method to improve TVAR-IF at low SNR; c) proposed to use TVAR-IF for time-varying FIR notch filter based FM jammer suppression in DSSS communications; d) developed TVAR model based time-varying optimum filters, including the TVAR based Kalman filter (TVAR-KF) and the TVAR based Wiener filter (TVAR-WF); e) developed a TVAR-WF based formulation of FM interference soft-cancellation in DSSS communications; and f) proposed a TVAR based linear prediction error (TVAR-LPE) filter for soft-cancellation of FM interference in DSSS communications. For the interference rejection problem, our TVAR-IF controlled notch filter yields high processing gain close to that using the known IF and much higher than that using the WVD based IF estimate. Furthermore, unlike the IF based notch filter approaches, the proposed soft-cancellation methods utilize the full spectral information captured by the TVAR model. Our soft-cancellation approaches, including TVAR-WF and TVAR-LPE, maintain at least the DSSS system performance expected when no filtering is used, even under estimated conditions. The latter is in contrast to the notch filter based approaches, which may cause deterioration of overall system performance at low jammer-to-signal ratios. / Ph. D.