Pretvorba frekvence vzorčenja digitalnega signala

magistrsko delo

Mirjam Skobe (Author), Aljaž Zalar (Mentor)

Abstract

Pretvorba frekvence vzorčenja digitalnega signala je pomemben proces za podrobnejšo analizo digitalnih signalov. Najti kakovostno programsko knjižnico, ki bi implementirala različne metode za to pretvorbo, pa je izjemno težko. Namen tega magistrskega dela je izdelati knjižnico v programskem jeziku C++, ki kot vhod dobi signal, vzorčen z neko frekvenco, kot izhod pa vrne signal, vzorčen z novo frekvenco. Pri tem uporabnik izbere frekvenco izhodnega signala in metodo pretvorbe. Knjižnica ima implementirane tri metode za pretvorbo signala; to so metoda trenutne vrednosti, metoda linearne interpolacije in metoda z uporabo nizkoprepustnega FIR filtra. Rezultati kažejo, da je za pretvorbo najhitrejša metoda trenutne vrednosti, ki pa v signal prinese veliko šuma in nejasnosti. Metoda z nizkoprepustnim FIR filtrom nam vrne najbolj kakovostne rezultate, vendar na račun hitrosti, saj je skoraj trikrat počasnejša od metode trenutne vrednosti. Do teh ugotovitev pridemo pri analizi teoretičnih signalov, ko pa si bolj podrobno pogledamo signale, ki nastanejo pri realnih meritvah, pa temu ni vedno tako. Realni primeri nam pokažejo, da metoda s FIR filtrom ni nujno najbolj kakovostna, še posebej kadar je sprememba frekvence vzorčenja zelo velika. V teh primerih se metoda linearne interpolacije ter metoda trenutne vrednosti odrežeta veliko bolje kot metoda s FIR filtrom.

Keywords

frekvenca vzorčenja;diskretni signal;interpolacijski algoritmi;večfazni filter;računalništvo in informatika;magisteriji;

Data

Language:	Slovenian
Year of publishing:	2021
Typology:	2.09 - Master's Thesis
Organization:	UL FRI - Faculty of Computer and Information Science
Publisher:	[M. Skobe]
UDC:	004(043.2)
COBISS:	93382659
Views:	136
Downloads:	30
Average score:	0 (0 votes)
Metadata:

Other data

Secondary language:	English
Secondary title:	Sample rate conversion of a digital signal
Secondary abstract:	Digital signal sampling frequency conversion is an important process for a more detailed analysis of digital signals. However, finding a quality software library that would implement different methods for this conversion is extremely difficult. The aim of this master's thesis is to create a library in the C ++ programming language, which, as an input receives a signal sampled with a certain frequency, and returns a signal sampled with a new frequency as an output. The user selects the frequency of the output signal and the conversion method. Three methods for signal conversion have been implemented: the sample-hold method, the linear interpolation method, and the method using a low-pass FIR filter. The results show that the fastest method for conversion is the sample-hold method, which brings a lot of noise and ambiguity to the signal. The method with a low-pass FIR filter has the highest quality results, but at the expense of speed, as it is almost three times slower than the sample-hold method. This is true for theoretical signals, but as we see in examples of real signals this is not always the case. In the examples, we see that the method with the FIR filter does not necessarily return the highest quality result, especially when the change in sampling frequency is very large. In these cases, the linear interpolation method and sample-hold method give much better results than the FIR filter method.
Secondary keywords:	sample rate;discrete signal;interpolation algorithms;polyphase filter;computer science;computer and information science;master's degree;Računalništvo;Univerzitetna in visokošolska dela;
Type (COBISS):	Master's thesis/paper
Study programme:	1000471
Embargo end date (OpenAIRE):	1970-01-01
Thesis comment:	Univ. v Ljubljani, Fak. za računalništvo in informatiko
Pages:	73 str.
ID:	14219204