Title Uređaji za obradu audio signala Title (english) Audio signal processing devices Author Paško Runjić Mentor Ivan Đurek (mentor)Committee member Ivan Đurek (predsjednik povjerenstva)Committee member Antonio Petošić (član povjerenstva)Committee member Mia Suhanek (član povjerenstva)Granter University of Zagreb Defense date and country 2014-09-17, Croatia Scientific / art field, TECHNICAL SCIENCES Abstract Uređaje za obradu audio signala dijelimo na uređaje za vremensku, frekvencijsku i dinamičku obradu signala. U uređaje za vremensku obradu signala spadaju delay, reverb, chorus, flanger, phaser i vremenski/frekvencijski pomak. Delay je najjednostavniji uređaj iz ove skupine, a radi tako da se ulazni signal zakasni, te se pribroji originalnom signalu. Jedan od prvih uređaja za kašnjenje je bio zasnovan na radu sa magnetskim vrpcama (tape delay), a kasnije i u analognoj tehnologiji (analogni
... More delay). Moderne izvedbe uređaja za kašnjenje zasnovane su na digitalnoj tehnologiji, gdje se signal nakon prolaska kroz A/D konverter digitalno obrađuje te na isti način zakasni te pridodaje originalnom signalu, prije ili poslije prolaska kroz D/A konverter. U domenu uređaja za vremensku obradu signala spadaju i uređaji za odjek, koji imitiraju odjeke prostorija iz stvarnog života (soba, dvorana, katedrala i sl…), pa ih tako dijelimo na: odjek dvorane, odjek sobe, odjek sa metalne ploče, odjek opruge), te one koji svoj rad temelje na digitalnoj tehnologiji (algoritamski i konvolucijski). Dvije dodatne izvedbe su odsječeni odjek i obrnuti odjek. Chorus je efekt također baziran na kašnjenju signala, gdje na zakašnjeli signal djeluje i dodatni NF oscilator, koji je zaslužan za osciliranje zakašnjelog signala, što daje prepoznatljiv zvuk. Flanger je isto tako baziran na kašnjenju, ali jako kratkom. Phaser zvuči slično kao flanger, ali nije na isti način baziran na kašnjenju: ulazni signal prolazi kroz široko pojasni filtar koji uzrokuje promjene faze, te se zbraja s ulaznim. Vremenski/frekvencijski pomak se odnosi na promjenu trajanja signala bez promjene spektra. Od uređaja za frekvencijsku obradu signala koristimo filtre, pa tako razlikujemo pojasni propust, pojasnu branu, nisko-propusni filtar i visoko propusni filtar, a isto tako i aktivne filtre, Butterworth filtre, Tschebyscheff filtre i Bessel filtre. Ekvalizatori (parametarski i grafički) temelje svoj rad na filtrima, kao i regulator boje tona. Dinamika označava raspon između najtišeg i najglasnijeg signala u zapisu. Uređaji za dinamičku obradu signala temelje svoj rad na regulaciji dinamike. Ti su uređaji limiter (ograničava daljnji rast razine signala), noise gate (utišava signal ispod određene razine), kompresor (ograničava razinu signala u jednom ili više koraka), te ekspander (regulira pojačanje signala ispod neke granične vrijednosti). Less Abstract (english) Audio effects are classified into three categories – ones that work in time domain, frequecy domain and ones that manipulate dynamics of a signal. Delay, reverb, chorus, flanger, phaser and time/pitch shifter are the ones that alter signal in time domain. Delay is the most simple effect from this category. The way it works is that input signal is being delayed and then added to the original signal. One of the first delay units used tapes, and later analog technology (analog delay).
... More Modern digital delays use digital technology, since original signal passes trough A/D converter, and then his delayed copy is added to the original before or after it passes trough D/A converter. Reverb units also belong int his category, since they emulate reverbs and echoes from real life spaces (hall, room, plate, spring…). Convolution and algorythm reverb use digital technology to emulate different spaces. Gated and reverse reverb are another two types oft his effect. Chorus effect works in a similar way as a delay, but usesLF oscillator, which makes chorus sound so recognizable. Flanger is also based on the delay, but very short one. Phaser sounds similar to flanger, but doesn't work the same way: input signal passes trough all-pass filter which causes different phase shifts, then this signal copy is being added to the original. Time/pitch shift manipulates time oft he signal without changing it's spectrum. Filters are devices commonly used since they operate in the frequency domain of a signal. Some of the types of filters are band pass, high pass, low pass, active, Butterworth, Tschebyscheff and Bessel filters. Equalizers (parametric and graphic), as well as tone controller units are based on filters operation. Dynamic range is the ratio between the largest and smallest values of a signal. Effects that alter dynamics of a signal are: Limiter, which attenuates peaks of a signal, noise gate, which cuts signal below certain treshold, compressor, which limits signal level and expander, which increases dynamic range of a signal. Less Keywords
audio
signal
jeka
odjek
tape
echo
filter
ekvalizator
kompresor
ekspander
noise gate
chorus
flanger
vremenski
frekvencijski
pomak
phaser
Keywords (english)
audio
signal
delay
reverb
tape
echo
filter
equalizer
compressor
expander
noise gate
chorus
flanger
time
pitch
shift
phaser
Language croatian URN:NBN urn:nbn:hr:168:073898 Study programme Title: Electrical Engineering and Information Technology Type of resource Text File origin Born digital Access conditions Closed access Terms of use Public note Created on 2018-02-05 17:53:05
