20.500.12556/RUL-186481 Detekcija jedrske magnetne resonance z USB osciloskopom Nuclear magnetic resonance detection with USB oscilloscope Diplomsko delo obravnava zasnovo, izdelavo in karakterizacijo kompaktnega pulznega NMR merilnega sistema na osnovi permanentnega magneta, katerega namen je merjenje gostote magnetnega pretoka vzorca iz signala prostega indukcijskega razpada (FID). Merilni sistem sestavljajo: NMR sonda s tuljavo, T/R stikalo z diodnim zaščitnim vezjem, dvostopenjska ojačevalna veriga ter aluminijasta Faradayeva kletka za elektromagnetno zaščito. Parametri sistema so bili optimizirani iterativno z namensko laboratorijsko opremo. Zajem signala in analiza pa je bila izvedena z napravo Digilent Analog Discovery PRO ter programsko opremo WaveForms. S FFT analizo zajetega FID signala je bila izmerjena Larmorjeva frekvenca vzorca f_L=12,665 MHz , iz katere je bila izračunana gostota magnetnega pretoka permanentnega magneta B_0=0,2975 T . Izmerjena gostota magnetnega pretoka je odvisna od temperature in staranja magneta. NMR sondo pa je potrebno namestiti na lokacijo v reži, kjer je homogenost polja najboljša. Zaradi tega bo tam tudi najboljše razmerje signal/šum. Zajet FID signal z značilnim eksponentnim pojemanjem amplitude nedvoumno potrjuje uspešno zaznavanje jedrske magnetne resonance v vzorcu. This thesis addresses the design, construction, and characterization of a compact pulsed NMR measurement system based on a permanent magnet, intended for measuring the magnetic flux density of a sample from the Free Induction Decay (FID) signal. The measurement system consists of: an NMR probe with a coil, a T/R switch with a diode protection circuit, a two-stage amplification chain, and an aluminium Faraday cage for electromagnetic shielding. The system parameters were optimized iteratively using dedicated laboratory equipment. Signal acquisition and analysis were performed using the Digilent Analog Discovery PRO device and the WaveForms software. By applying FFT analysis to the acquired FID signal, the Larmor frequency of the sample was measured as f_L=12,665 MHz , from which the magnetic flux density of the permanent magnet was calculated as B_0=0,2975 T . The measured magnetic flux density is dependent on temperature and magnet ageing. Furthermore, the NMR probe must be positioned at a location within the gap where the field homogeneity is greatest, as this location will also yield the best signal-to-noise ratio. The acquired FID signal, exhibiting characteristic exponential amplitude decay, unambiguously confirms the successful detection of nuclear magnetic resonance in the sample. NMR magnetizacija gostota magnetnega pretoka signal prostega indukcijskega razpada Digilent Analog Discovery PRO NMR magnetization magnetic flux density Free Induction Decay signal Digilent Analog Discovery PRO true false false Slovenski jezik Angleški jezik Diplomsko delo/naloga 2026-09-02 10:50:42 2026-09-02 10:51:00 2026-09-04 03:32:10 0000-00-00 00:00:00 2026 0 0 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 1970-01-01 63319 Peskar_Lenart_-_Detekcija_jedrske_magnetne_resonance_z_USB_osciloskopom.pdf Peskar_Lenart_-_Detekcija_jedrske_magnetne_resonance_z_USB_osciloskopom.pdf 1 F594017874A2FBCECCE2E75EBC90B4E9 ca5d184e5ec33158e489c0fbad03fcd47015541ec8fe14820bfa0a7126f1317e fe62d058-a6aa-11f1-9b0d-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=245744 Fakulteta za elektrotehniko 0 0 0