Lecture

Filtering before Sampling

Graph Chat

Chat with Graph Search

Ask any question about EPFL courses, lectures, exercises, research, news, etc. or try the example questions below.

DISCLAIMER: The Graph Chatbot is not programmed to provide explicit or categorical answers to your questions. Rather, it transforms your questions into API requests that are distributed across the various IT services officially administered by EPFL. Its purpose is solely to collect and recommend relevant references to content that you can explore to help you answer your questions.

In course

CS-119(a): Information, Computation, Communication

D'une part, le cours aborde: (1) la notion d'algorithme et de représentation de l'information, (2) l'échantillonnage d'un signal et la compression de données et (3) des aspects liés aux systèmes: ordinateur, mémoire, etc. D'autre part, le cours donne une i ...

Description

This lecture discusses the importance of filtering a signal before sampling it, to avoid the stroboscopic effect caused by undersampling. Various solutions are presented, including spectral decomposition and the use of ideal low-pass filters. Examples with sound signals are provided to illustrate the concepts.

In MOOC

Information, Computation, Communication: Introduction to computational thinking

In the first part of the course, we'll look at how algorithms can be used to solve a problem in a very concrete way, leading us on to one of the great questions of modern theoretical computer science. The second part of the course will be devoted to information and communication: we'll be looking at a number of topics, including information representation, signal processing, data compression, communication and cryptography.

Instructors (3)

Dan-Cristian Tomozei

Mirjana Stojilovic

Mirjana Stojilović received the Dipl. Ing. and Ph.D. degrees from the School of Electrical Engineering, University of Belgrade, in 2006 and 2013, respectively. From 2010 to 2013, she was collaborating with the Processor Architecture Laboratory at EPFL, visiting periodically as a Guest Researcher. From 2013 to 2016, she was working at the University of Applied Sciences Western Switzerland as a senior researcher, and at EPFL as a lecturer. She joined Parallel Systems Architecture Lab at EPFL in October 2016. Mirjana's main research interests include electronic design automation, reconfigurable computing, electromagnetic-compatibility and signal-integrity issues, and hardware security. Mirjana Stojilović serves on the program committee of the FPGA, FPL, and FCCM conferences and as a reviewer for IEEE TCAD, TVLSI, TC, TEMC, IEEE Access and ACM TRETS. She received the Best Paper Award at 2016 International Symposium on Electromagnetic Compatibility (EMC Europe 2016), Young Scientist Award at 33rd International Conference on Lightning Protection (ICLP2016), and the Young Author Best Paper Award at the 20th Telecommunication Forum in Belgrade (TELFOR 2012). In 2015, the EPFL School of Computer and Communication Sciences (IC) presented her with the Teaching Award.

Olivier Lévêque

Olivier Lévêque was born in Switzerland in 1971. He received the physics diploma from EPFL in 1995 and completed his PhD in mathematics at EPFL in 2001. Since then, he has been with the Laboratory of Information Theory at EPFL. He spent the academical year 2005-2006 at the Electrical Engineering Department of Stanford University, where he was appointed as lecturer. His research interests include stochastic analysis, random matrices, wireless communications and information theory.

Official source

Ontological neighbourhood

Information engineering

Signal processing: Filtering theory

Related concepts (24)

Low-pass filter

A low-pass filter is a filter that passes signals with a frequency lower than a selected cutoff frequency and attenuates signals with frequencies higher than the cutoff frequency. The exact frequency response of the filter depends on the filter design. The filter is sometimes called a high-cut filter, or treble-cut filter in audio applications. A low-pass filter is the complement of a high-pass filter. In optics, high-pass and low-pass may have different meanings, depending on whether referring to the frequency or wavelength of light, since these variables are inversely related.

High-pass filter

A high-pass filter (HPF) is an electronic filter that passes signals with a frequency higher than a certain cutoff frequency and attenuates signals with frequencies lower than the cutoff frequency. The amount of attenuation for each frequency depends on the filter design. A high-pass filter is usually modeled as a linear time-invariant system. It is sometimes called a low-cut filter or bass-cut filter in the context of audio engineering. High-pass filters have many uses, such as blocking DC from circuitry sensitive to non-zero average voltages or radio frequency devices.

Band-pass filter

A band-pass filter or bandpass filter (BPF) is a device that passes frequencies within a certain range and rejects (attenuates) frequencies outside that range. In electronics and signal processing, a filter is usually a two-port circuit or device which removes frequency components of a signal (an alternating voltage or current). A band-pass filter allows through components in a specified band of frequencies, called its passband but blocks components with frequencies above or below this band.

Sampling (statistics)

In statistics, quality assurance, and survey methodology, sampling is the selection of a subset or a statistical sample (termed sample for short) of individuals from within a statistical population to estimate characteristics of the whole population. Statisticians attempt to collect samples that are representative of the population. Sampling has lower costs and faster data collection compared to recording data from the entire population, and thus, it can provide insights in cases where it is infeasible to measure an entire population.

All-pass filter

An all-pass filter is a signal processing filter that passes all frequencies equally in gain, but changes the phase relationship among various frequencies. Most types of filter reduce the amplitude (i.e. the magnitude) of the signal applied to it for some values of frequency, whereas the all-pass filter allows all frequencies through without changes in level. A common application in electronic music production is in the design of an effects unit known as a "phaser", where a number of all-pass filters are connected in sequence and the output mixed with the raw signal.

Related lectures (64)

Sampling: Signal Reconstruction and Aliasing

Covers the importance of sampling, signal reconstruction, and aliasing in digital representation.

LTI Systems: Analysis and Properties

Covers the analysis and properties of Linear Time-Invariant (LTI) systems.

Sampling and Reconstruction

Covers sampling, Fourier Transform, and reconstruction using low-pass filters in signal processing.