Fazno-osjetljivo pojačalo

master's thesis

• Title (english): Lock-in amplifier
• Author: Alan Stojanović
• Mentor: Emil Tafra (mentor)
• Committee member: Emil Tafra (predsjednik povjerenstva)
• Committee member: Katarina Jeličić (član povjerenstva)
• Committee member: Vedran Đerek (član povjerenstva)
• Committee member: Maja Planinić (član povjerenstva)
• Committee member: Mario Novak (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Physics); Zagreb
• Defense date and country: 2022-02-08, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Physics

Abstract

Fazno-osjetljivo iliti ”lock-in” pojačalo je uređaj koji po principu lock-in detekcije izdvaja željeni signal iz šuma neželjenih signala što omogućava njegovo mjerenje. Ovakvi uređaji rezultat su skladnog djelovanja velikog broja osjetljivih komponenti radi čega su i vrlo skupi. U ovome radu se iz tog razloga bavimo jednom alternativom niskobudžetnom realizacijom lock-in pojačala te je cilj opisati ju i usporediti sa standardnom komercijalnom verzijom PARC model 5210 dvofaznim lock-in pojačalom. Nakon opisa njihovog rada ispituje se frekventni opseg niskobudžetne realizacije te se zatim obje realizacije primjenjuju na jednostavnom sklopu. Usporedbom dobivenih rezultata zaključujemo da je niskobudžetno lock-in pojačalo definitivno primjenjivo i sposobno izdvojiti signal amplitude reda veličine 10^−4 V uz prisutni šum prikazan slikom 5.7. Rad niskobudžetne realizacije na visokoj frekvenciji prikazan je slikama 5.1 i 5.2 dok je na niskoj frekvenciji prikazan slikama 5.3 i 5.4. Frekventni opseg niskobudžetnog lock-in pojačala je otprilike 10 Hz − 100 kHz te je u ovom segmentu ono usporedivo s model 5210 dvofaznim lock-in pojačalom za koje je frekventni opseg 0.5 Hz - 120 kHz [9].

Abstract (english)

Phase-sensitive or ”lock-in” amplifier is a device which singles out wanted signal from a noisy background using a method of lock-in detection which then allows its measurement. These types of devices are a result of harmonious operation of large number of components which makes them very expensive. Therefore, in this thesis we are dealing with one alternative low-cost variant of lock-in amplifier and aim is to describe it and compare it to a standard commercial variant of PARC model 5210 dual phase lock-in amplifier. After the description of their functioning, frequency range of the low-cost variant is tested and then both variants are applied on a simple circuit. By comparing obtained results, we conclude that low-cost lock-in amplifier is definitely applicable and capable of singling out a signal of amplitude in the range of 10^−4 V in a noisy environment shown with picture 5.7. Functioning of a low-cost lock-in amplifier on high frequency is shown on pictures 5.1 and 5.2 while on the low frequency it is shown with pictures 5.3 and 5.4. Frequency range of a low-cost lock-in amplifier is around 10 Hz − 100 kHz which at least in this segment, makes it comparable with model 5210 dual phase lock-in amplifier for which the frequency range is 0.5 Hz - 120 kHz [9].

• Keywords: lock-in detekcija; demodulacija; referentna frekvencija; faza; niskobudžetno lock-in pojačalo; sinkroni demodulator; PARC model 5210 dvofazno lock-in pojačalo
• Keywords (english): lock-in detection; demodulation; reference frequency; phase; Low-cost lock-in amplifier; synchronous demodulator; PARC model 5210 dual phase lock-in amplifier
• Language: croatian
• URN:NBN: urn:nbn:hr:217:288537
• Study programme: Title: Physics; specializations in: Education; Course: Education; Study programme type: university; Study level: integrated undergraduate and graduate; Academic / professional title: magistar/magistra edukacije fizike (magistar/magistra edukacije fizike)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2022-03-31 11:27:14