<p>For a long time radio devices have been constructed in hardware with a fixed functionality. This way of constructing radio devices is starting to change with the concept of Software Defined Radio (SDR) evolving. The SDR concept leads to more flexible and long lasting radio devices. In order to make the radio software more standardized and portable, the U.S. military has defined the Software Communication Architecture (SCA). Internal communication within the SCA is done by CORBA, which limit waveforms to be only distributed over CORBA-capable hardware. The U.S. military has defined the Modem Hardware Abstraction Layer(MHAL) to enable distribution over devices not supporting CORBA. This thesis presents an implementation of MHAL and an underlying transport mechanism based on Ethernet. The implementation is done for the OSSIE package. The implementation is evaluated both in terms of real-time and throughput performance. The results show that MHAL achieves good performance, in comparison to CORBA, and can greatly be used to distribute waveforms over both CORBA and non-CORBA capable devices.</p>

<p>Software Defined Radio (SDR) is a conception of implementing radio functions in computer software, instead of having electronics performing the functions. This thesis aims to compare two different ways of implementing these functions, or waveforms.</p><p>The Software Communications Architecture (SCA) is an open standard developed by the United States Department of Defense. It uses a CORBA interface environment to make waveform applications interoperable and platform independent. This method of developing SDR is compared to an open-source initiative going by the name GNU Radio.</p><p>Two waveform applications are developed, one transmitter using SCA, and one receiver using GNU Radio. The analog radio interface is simulated using the sound cards of two regular PCs. The development is done using the C++ and Python programming languages.</p><p>This thesis examines pros and cons of the two SDR methods, as well as performing studies of Software Defined Radio in general.</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>

For a long time radio devices have been constructed in hardware with a fixed functionality. This way of constructing radio devices is starting to change with the concept of Software Defined Radio (SDR) evolving. The SDR concept leads to more flexible and long lasting radio devices. In order to make the radio software more standardized and portable, the U.S. military has defined the Software Communication Architecture (SCA). Internal communication within the SCA is done by CORBA, which limit waveforms to be only distributed over CORBA-capable hardware. The U.S. military has defined the Modem Hardware Abstraction Layer(MHAL) to enable distribution over devices not supporting CORBA. This thesis presents an implementation of MHAL and an underlying transport mechanism based on Ethernet. The implementation is done for the OSSIE package. The implementation is evaluated both in terms of real-time and throughput performance. The results show that MHAL achieves good performance, in comparison to CORBA, and can greatly be used to distribute waveforms over both CORBA and non-CORBA capable devices.

CMMB (China Multimedia Mobile Broadingcasting) is a wireless broadcastingchannel standard for low bandwidth, low cost hand-held digital TV is adopted byall continental Chinese government TV broadcasting companies and some HongKong private TV broadcasting companies. The business potential is high, yet thefuture is hard to predict because it might be replaced by GB200600 or DTMB. Thedigital modulation is based on OFDM with pilot supporting channel estimationand equalization and CP supporting multi-path induced ISI problems.This thesis investigates the implement a CMMB system using a SDR platform.Simulation chain was implemented using MATLAB with full data precision includingCMMB transmitter and receiver. The transmitter behavior model includes RSencoder, LDPC encoder, OFDM modulation, etc. The receiver behavior modelincludes OFDM demodulation, channel estimation, channel equalization, LDPCdecoder, RS decoder, etc. Different channel models emulating pathloss, whitenoise, multi-path, and glitch were modeled. Based on the simulation chain andchannel models, T-domain, F-domain channel estimator and equalizer were implemented,optimized. Optimized TD-FD models for different mobility scenarioswere proposed. The focus of the thesis is on 2D (FD-TD) channel estimation andequalization.

The increase in speed and density of programmable logic devices such as Field Programmable Gate Arrays (FPGA) enables ever more complex designs to be constructed within a short time frame. The flexibility of a programmable device eases the integration of a design with a wide variety of components on a single chip. Since Frequency Modulation (FM) is an analog modulation scheme, performing it in the digital domain introduces new challenges. The details of these challenges and how to deal with them are also explained. This thesis presents the design of a digital stereo FM modulator including necessary signal processing, such as filtering, waveform generation, stereo multiplexing etc. The solution is comprised of code written in Very high speed integrated circuit Hardware Description Language (VHDL) and a selection of free Intellectual Property (IP)-blocks and is intended for implementation on a Xilinx FPGA. The focus of the thesis lies on area efficiency and a number of suggestions are given to maximize the number of channels that can be modulated using a single FPGA chip. An estimation of how many channels that can be modulated usingthe provided FPGA, Xilinx XC6SXL100T, is also presented.

From a HF propagation point of view, the ionospheric layers act as partially conducting media (plasma) in which a transmitted radio wave can reflect upon.A way of determining whether a radio wave with a given frequency will reflect from the ionosphere or completely penetrate is to utilize special radar instruments know as ionosondes or chirp sounders. The technique is widely used by amateur enthusiasts and military radio users for monitoring available radio channel links between two remote locations and can often serve as a base for HF radio prognoses.The objective of this Bachelor’s Thesis was to explore, implement and test a single channel receiver for monitoring ionospheric sounders. The implementation is based on Software Defined Radio (SDR) technology and relies on the GNU Chirp Sounder (gcs) open source script program.

Software Defined Radio (SDR) is a conception of implementing radio functions in computer software, instead of having electronics performing the functions. This thesis aims to compare two different ways of implementing these functions, or waveforms. The Software Communications Architecture (SCA) is an open standard developed by the United States Department of Defense. It uses a CORBA interface environment to make waveform applications interoperable and platform independent. This method of developing SDR is compared to an open-source initiative going by the name GNU Radio. Two waveform applications are developed, one transmitter using SCA, and one receiver using GNU Radio. The analog radio interface is simulated using the sound cards of two regular PCs. The development is done using the C++ and Python programming languages. This thesis examines pros and cons of the two SDR methods, as well as performing studies of Software Defined Radio in general.

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. 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. 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. / 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. 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. Analyserna har visat bra resultat, och möjligheterna att bygga en komersiell mjukvarudefinierade radiomottagare för VHF-bandet ses som goda.

Our laboratory has previously shown that exposure to social disruption (SDR) the week prior to Theiler’s murine encephalomyelitis virus (TMEV) infection exacerbates disease course, resulting in increased infection-related sickness behaviors, motor impairment, CNS viral titers, and CNS inflammation. These adverse effects of SDR were prevented by ICV infusion of a neutralizing antibody to IL-6 during the stress exposure period. These findings suggest that stress-induced increases in IL-6 are necessary to exacerbate acute TMEV infection, but the exact mechanism remains unknown. This thesis tested the hypotheses that SDR up-regulates central cytokine expression, exacerbates TMEV infection through cross-sensitization of virus-induced cytokine expression, and that social rank modulates the effect of SDR. In Experiment 1, Balb/cJ mice underwent the 0, 1, or 6 SDR sessions and were then sacrificed 0, 2, or 12 hours post SDR. Experiment 2 subjects received ICV infusions of either IL-6 neutralizing antibody or its vehicle before each of six 2 h SDR sessions or the control condition, the week prior to infection. In Experiment 3 mice were tested for pre-existing social rank prior to SDR and infection. Results indicate that (1) SDR increases virus-induced IL-6, IL-1B, and CD11b mRNA expression in brain,that these SDR-induced increases and acute TMEV exacerbation are prevented by ICV infusion of the IL-6 neutralizing antibody during the stress exposure period, and that (2) social rank does not modulate affects of SDR but baseline anxiety does. These findings suggest that SDR exacerbates acute TMEV infection through cross-sensitization of virus-induced cytokine expression and that baseline anxiety is a significant modulator of SDR.