International Telemetering Conference Proceedings / October 27-30, 1997 / Riviera Hotel and Convention Center, Las Vegas, Nevada / The basic building blocks for implementing complex waveform generators using a look-up table approach are random access memory (RAM) and read only memory (ROM) devices. Due to technological advancements in field programmable gate array (FPGA) development, these devices have the ability to allocate large amounts of memory elements within the same structure. The self containment property makes the FPGA a suitable topology for complex waveform generation applications. In addition, this self containment property significantly reduces implementation costs by reducing the number of external components required to support many applications. This paper examines the use of FPGA’s in various complex waveform generation applications. In particular, a discussion will ensue examining possible mappings of the time domain response of the complex waveform into memory elements of the FPGA. The analyses and examples contained in the sequel are from existing waveform generation applications, developed for Gauissian Minimum Shift Keying (GMSK) and Unbalanced Quadriphase Shift Keying (UQPSK) modulation formats.

CPM advantageous in spectral efficiency because of its continuity of the phase in modulation. One of the CPM example is GMSK, which has been applied to the wireless GSM system. The conventional demodulaton og CPM is achieved by Viterbi algorithm. This is because of the state transition structure for the dynamic description of phase of the CPM signal. Furthermore, the state transition can be presented by a trellis diagram, which can be efficiently solved by Viterbi algorithm based upon the strategy of selecting best survivor path to a maximum likelihood criterion. The best survivor path is measured by the Euclidean distance in modulation in this thesis. Another demodulation method proposed by us is the famous BCJR algorithm. BCJR which is based upon the posteriori probabilities is a alternative method for decoding the convolution code. We compare the BCJR and Viterbi algorithm for the demodulation of the GMSK system. Experiment results demonstrate that BCJR has a better error probability than the Viterbi algorithm. Also, we compare different GMSK system for different overlapping length and modulation index. The best combination of L and h suggested by pur experiments is the case of L=3, and h=3/4.

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International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada / Three different demodulators applicable to the coherent demodulation of binary Gaussian Minimum Shift Keying (GMSK) signal are described and their performance compared. These include a near-optimal trellis demodulator, which utilizes two matched filters and Viterbi algorithm to carry out maximum likelihood sequence estimation, and a singlefilter threshold demodulator with and without pulse equalization. The performance of these demodulators in noise and adjacent channel interference (ACI) are compared for several signal BT products. The equalized threshold demodulator is shown to perform nearly as well as the near-optimal trellis demodulator in additive white Gaussian noise (AWGN), and substantially outperform the trellis demodulator under severe ACI condition.

International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada / The design, implementation, and performance of a digital modem employing Gaussian minimum shift keying (GMSK) is described. The GMSK modem is implemented in field programmable gate array (FPGA) chips, and a laboratory test setup was developed to validate its performance for a signal BT value of 1/5. The measured spectrum of the GMSK modem and its bit error rate (BER) performance, which are found in very close agreement with those of theory and simulation, are presented in this paper.

No description available.

<p>DARC är ett sätt att sända digital information via FM-rundradionätet. Moduleringsmetoden för DARC är GMSK. Målsättningen var att jämföra kostnad/komplexitet och strömförbrukning för olika sätt att demodulera GMSK. Tre icke-koherenta demodulatorer och en koherent demodulator har jämförts. Man vill veta hur stor resursanvändningen var för olika FPGAer. De olika demodulatorerna har beskrivits med VHDL.</p>

<p>The purpose of this thesis work is to examine the possibility of building a software-defined radio (SDR) for the VHF-band. The goal is to accomplish this with as few components as possible, thus cutting down the size and the production cost.</p><p>An SDR solution means that the sampling of the signal is done as close to the antenna as possible. The wide bandwidth needed in such a product is achieved by using SP Devices algorithm for time-interleaved ADCs. Two hardware prototypes and two versions of the software were designed and implemented using this technology.</p><p>They were also analyzed within this thesis work. The results proved to be good, and the possibilities to produce a commercial software-defined radio receiver for the VHF-band are good.</p> / <p>Syftet med det här examensarbetet är att utreda möjligheten att bygga en mjukvarustyrd radiomottagare (SDR) för VHF-bandet. Målet är att göra detta genom att använda så få komponenter som möjligt, och därigenom minska storleken och produktionskostnaden.</p><p>En SDR lösning ger att samplingen kommer att ske så nära antennen som möjligt. Den stora bandbredd som behövs för en sådan produkt uppnås genom att använda SP Devices algoritm för att ''tidsinterleava'' höghastighets ADC:er. Två hårdvaruprototyper och två versioner av mjukvaran har designats och implementerats.</p><p>Analyserna har visat bra resultat, och möjligheterna att bygga en komersiell mjukvarudefinierade radiomottagare för VHF-bandet ses som goda.</p>

Instruments for analyzing radio signals are very expensive and their full capacity is seldom used outside the research and development and the type approval departments. Instrument manufacturers have historically integrated the hardware and the software into a single unit. But some instrument manufacturers are beginning to change this. The software is moved to a PC and the hardware samples the time continuous signal and sends it to the computer for analysis or for saving it on a file. Since the data from the hardware is in a raw format this opens up for other than the instrument manufacturer to supply the software. This thesis presents algorithms for calculating power, phase error and frequency error. It is shown that the results from these algorithms are comparable to the results from commercial analysis software. It is concluded that it is possible to create own analysis software at a reasonable cost with the possible downside of it being slower than commercial software.

DARC är ett sätt att sända digital information via FM-rundradionätet. Moduleringsmetoden för DARC är GMSK. Målsättningen var att jämföra kostnad/komplexitet och strömförbrukning för olika sätt att demodulera GMSK. Tre icke-koherenta demodulatorer och en koherent demodulator har jämförts. Man vill veta hur stor resursanvändningen var för olika FPGAer. De olika demodulatorerna har beskrivits med VHDL.