Softare radio design in LabVIEW

Diplomsko delo obravnava postopke načrtovanja programsko definiranega radia (ang. Software Defined Radio = SDR). Uvodno poglavje podaja opis osnovne strukture SDR sprejemnika in podroben pregled arhitekture programsko nastavljivega digitalnega prenosnega sistema. Vsi praktični eksperimenti so načrtovani v programskem okolju LabVIEW in z uporabo univerzalne strojne opreme (USRP=Universal Software Radio Peripheral). Podan je pregled osnovnih gradnikov v vezavah elektronskih komponent programabilnega sprejemnika in oddajnika. Poleg komponent strojne opreme je opisan tudi vpliv programsko nastavljivih parametrov na delovanje radia. Poleg osnovnega načina uporabe USRP naprave v povezavi z osebnim računalnikom je prikazan še avtonomen način procesiranja signalov na vgrajenem FPGA čipu. Pred načrtovanjem programsko definiranega radia so podane tehnične specifikacije uporabljene NI USRP naprave, ki določajo omejitve frekvenčnega območja analognih signalov in procesnih zmogljivosti pri obdelavi digitalnih signalov. Uporabnik tako dobi vpogled, v katerem območju frekvenc se z razpoložljivo NI USRP opremo lahko izvajajo eksperimenti. Po uvodnem pregledu arhitekture NI USRP naprav sledi v drugem poglavju opis navodil za pripravo osebnega računalnika za delo s programsko definiranim radijem, kar vključuje instalacije programskega okolja LabVIEW, gonilnika za NI USRP in programskih razširitev za načrtovanje bolj zahtevnih RF aplikacij. Začetni eksperimentalni zgledi v tretjem poglavju predstavijo osnovno uporabo sprejemnika: način za vzpostavitev povezave z napravo, nastavljanje parametrov naprave in zajemanje omejenega števila vzorcev. Osnovni eksperimenti so v nadaljevanju nadgrajeni z zankami za neprestano zajemanje in preslikovanje signala v frekvenčni prostor. Podan je tudi predlog programske arhitekture za hitrejše paralelno zajemanje vzorcev in obdelavo signalov. Podobni zgledi eksperimentov kot za sprejemnik so v nadaljevanju podani tudi za prikaz delovanja in nastavitev osnovnih programskih gradnikov USRP oddajnika. Z množico zgledov testnih aplikacij so v tretjem poglavju opisani eksperimenti za preverjanje dinamičnega območja ojačevalnikov in meritev različnih motenj v delovanju USRP naprav. Pri načrtovanju spektralnega analizatorja smo uporabili možnost hkratnega spreminjanja programabilnih parametrov centralne frekvence in pasovne širine med delovanjem sprejemnika na NI USRP napravi. Avtomatizirano spreminjanje centralne frekvence nam omogoča izgradnjo širokopasovnega spektralnega analizatorja, ki ga uporabimo za zaporedno analizo spektra v podpasovih po celotnem frekvenčnem območju delovanja USRP naprave. NI USRP napravo smo v četrtem poglavju uporabili za izgradnjo analognega prenosnega sistema. Zaradi razširjenosti in velikega števila radijskih postaj v UKV pasu smo izbrali FM modulacijo. Podan je primer sprejemnika, ki zajet signal FM demodulira in predvaja na zvočniku osebnega računalnika. Na drugi USRP napravi smo sestavili programsko kodo FM oddajnika nizke moči, ki omogoča prenos testnega modulacijskega signala ali zvokovnega signala iz WAV datoteke. V zaključku četrtega poglavja je predstavljena združena programska koda za oddajo in sprejem FM signalov. Pred načrtovanjem digitalnega prenosnega sistema je v petem poglavju najprej podan postopek oblikovanja podatkovnih paketov z dodano psevdonaključno sekvenco, ki omogoča pravilno sinhronizacijo bitov v sprejemniku. Programsko okolje LabVIEW omogoča izvedbo različnih digitalnih modulacij, zato so predstavljeni programski moduli modulatorjev in demodulatorjev z opisi nastavitev glavnih parametrov. V zaključku je predstavljen USRP prenosni sistem, ki združuje kodo za paketiranje podatkov, PSK modulacijo in mešanje signalov v oddajniku in kodo za mešanje in PSK demodulacijo ter branje podatkovnih bitov iz sinhroniziranih paketov v sprejemniku. Delovanje eksperimentalnega prenosnega sistema je preverjeno s prenosom tekstovnih sporočil po radijskem kanalu.The theme of the diploma thesis is the design of the software-defined radio in LabVIEW. On the begining, software defined radio architecture is reviewed. Corelation between various parameters and system hardware is highlighted. USRP can be used in several ways, depending on the needs and knowledge of the user. Each of the ways is presented to the user to get a sense what are the advantages of a single regime of use. The mode, where USRP is used as a computer periphery, is highlighted, because this is the mode, which is used for all the examples in this thesis. USRP specifications are given to the user to get feeling, what are the limitations of use and which frequency bands and bandwidths can be used for measurements and applications. Detailed review of NI USRP devices is followed by a computer preparation, which includes explanations about LabVIEW programming environment, NI USRP driver and usable add-ons and toolkits. After that the first practical examples follows. On a basic transmitter and receiver examples, connection with hardware, system parameters configuration, fetching and writing data to NI USR is explained. First examples show code for finite data acqusition, which is later upgraded by countinous execution and signal processing like FFT to get spectrum of acquired signal. When signal processing is introduced, advanced programming architectures are shown to speed up program execution. After that, example for verifiying the dynamic range of programmabe output amplifier is represented. All examples till now included system parameter configuration before program is run. After this example, examples includes dynamic system parameter configuration, which means, that parameter scan be changed during operation. Dynamic parameter configuration allow us to change central frequency and bandwidth, which means that we can build wideband spectral analyser for constant spectrum signals. NI USRP can be used for an analog modulation. Due to the prevalence and large number of radio stations in the UKV band, FM analog modulation is selected. First example shows FM receiver, which can play demodulated signal on a PC loadspeaker. After that, FM transmitter is being build. FM transmitter can transmitt FM modulated sine wave or any other wave in later iterations of the transmitter code. Than FM transmitter is upgraded, to be able to transmitt signal saved in WAV file or to transmit signal, acquired from AUX input of a soud card. LabVIEW allow us to perform digital modulations and demodulations. In the last chapter, all possible digital modulations are explained. At the end, digital communication system is build to demonstrate usage of PSK modulation for simple one way chat application

Extraction of Polyphenols from Slovenian Hop (<i>Humulus lupulus</i> L.) Aurora Variety Using Deep Eutectic Solvents: Choice of the Extraction Method vs. Structure of the Solvent

Polyphenols from Slovenian hops (Humulus lupulus L.) of the Aurora variety were extracted by different methods and using classical solvents and several deep eutectic solvents (DES) based on choline chloride as the hydrogen bond acceptor component. The obtained extract solutions were analyzed by HPLC for the content of extracted α- and β-acids and extracted xanthohumol. It was found that choline chloride:phenol DES concentrated aqueous solution had an extraction efficiency close to that of diethyl ether, which is considered one of the best classical extraction solvents for polyphenols from hops. The comparison of the extraction efficiency with other choline chloride-based DESs showed that the chemical similarity of the phenol ring in the solvent DES with the polyphenols in hops may be crucial for a highly efficient extraction with choline chloride:phenol DES. On the other hand, the choice of extraction method and the viscosity of the solvents tested seem to play only a minor role in this respect. As far as we know, this is the first study to attempt to relate extraction efficiency in the extraction of hydrophobic solutes to the compressibility of the DES extractants, the latter of which may be correlated with the extent of hydrophobic hydration around the DES components. In addition, using the heating and stirring method for the preparation of choline chloride-based DES concentrated aqueous solutions we found no support for the occurrence of water in two different roles (in the structural and in the dilution role) in these solvents