Index
Digital Signal Processing Page
General information
DSPs are special microprocessors designed to executerepetitive math-intensive algorithms. Today many embeddedapplications require both types of processors. Digital Signal Processors have approximately the same level ofintegration, the same clock frequencies as general purposemicroprocessors. Pn signal processing tasks DSPs overtake general purpose processors from 2 to 3 order in speed. This is because of architectural differences. Typical DSP application fields are audio signal processing, video signal processing and telecommunications devices. Digital signal processing requires a large amount of real-timecalculations. The most common operation in digital signal processing is thesum of products calculation. Among such operations are well known convolution and Discrete Fourier Transform. Digital Signal Processors vs. Universal Microprocessors 9To increase the speed, digital signal processors usually havemany specialized arithmetic units, which can operatesimultaneously. To calculate the sum of products, typical DSPoperation, all DSPs have multiplier and accumulator and twooperations multiplication and addition can be implemented duringone cycle. Some DSPs can fulfil simultaneously even FFTbutterfly. All DSPs contain shifter to shift operands without lossadditional time.Digital Signal Processors are designed for realtimecalculation. Fixed sampling rate leads to necessity to haveregular instruction cycle. Such regular instruction cycle is achievedin RISC (reduced instruction set computer) microprocessors byrestricting the instruction set. But in DSP the same is achieving byhardware increasing the speed of important complex instructions,for example multiplications.Universal microprocessors were designed simple and cheappersonal computers. Universal CISC (complex instruction set computer)microprocessors have a large variety of command cycle duration. For example in 8086 microprocessor addition - 3 clocks and multiplication -more 100 clocks.Some features of DSP in are included in recent universal microprocessors, which makes the leaster processor capable of supporting many applications which earlier needed special DSPs.
- EDN 2005 DSP Directory: Targeted DSPs take aim - DSP options continue to expand and are targeting optimized configurations for specific applications. Check out the inaugural online table for a detailed view of current device and core offerings. Rate this link
- 2004 DSP directory - EDN's DSP directory and list of resources supporting digital-signal processing Rate this link
- Adaptyv - practical information concerning the design of digital signal processing systems Rate this link
- Articles, Papers, and Presentations by BDTI Authors - good collection of DSP articles Rate this link
- Analog Devices DSP (tricks, source code...) Rate this link
- comp.dsp FAQ - FAQs (Frequently asked questions with answers) on Digital Signal Processing Rate this link
- Conventional DSP or configurable microcontroller: which way to go? - Engineers of DSP-based systems are in a quandary over whether to use a conventional DSP or one of the new configurable microcontrollers. The technical challenges of MP3 decoding provide the basis for comparing traditional DSPs with upstart configurable micros. Rate this link
- Creating quasistatic, parameterized FPGA designs - New configuration approaches can lead to easier system designs, benefiting a range of applications. Reducing the overall pin count, interface complexity, and resource usage also enables FPGAs to be a flexible digital-signal-processing alternative to DSP architectures. Rate this link
- DSP and Communications Links Directory - resources on the net for dsp and communications design Rate this link
- DSP-architecture directory 2000 - EDN's annual DSP directory helps in sorting through the myriad DSP devices Rate this link
- DSP Boards: A Buyer's Guide - Fortunately, it's not necessary for a designer to start from scratch when dealing with complex DSP chips, an essential component for many communication systems- thanks to an array of preconfigured and customizable DSP boards and related software. Rate this link
- DSP Buyers Guide - selecting the right DSP for a given project is no simple matter Rate this link
- DSP Compilers: A Buyer's Guide - Your comm DSP's performance depends heavily on your compiler choice, so it pays to know your options. Rate this link
- DSP Directory 2001 - DSP chip directory from EDN Magazine Rate this link
- dspGuru Digital Signal Processing Central - Digital Signal Processing (DSP) is a complex subject. dspGuru's purpose is to promote resource-sharing among DSP designers. Rate this link
- DSP Related Mailing Lists - mailing lists, related to DSP, on which you can subscribe Rate this link
- DSPs for next-generation cell phones balance performance and power - DSP vendors are fighting the battle on several fronts for high-performance, low-power operation and offering scalable architectures and optimized instruction sets. Rate this link
- DSP System Integration Rate this link
- Embedded microprocessors and DSPs: considerations for converging technologies - If you're considering a change from a traditional embedded processor to a DSP device, you're not alone, EDN Web Exclusives article in pdf format Rate this link
- FAQs (Frequently asked questions with answers) on Digital Signal Processing - world-wide web version of the comp.dsp FAQ Rate this link
- Fixed or floating? a pointed question in DSPs - designers considering DSP applications must first decide whether to commit their designs to fixed- or floating-point DSPs Rate this link
- FPGAs DiSPlay their processing prowess - Does the performance-power-price product of your software-centric approach no longer compute? Do you need a nimbler platform than a hard-wired ASIC can provide? Programmable logic may be your answer, but carefully calculate the trade-offs to correctly solve your problem. Rate this link
- General-purpose ?Ps for DSP applications: consider the trade-offs - using general-purpose processors instead of dedicated DSPs for DSP-intensive applications has some advantages, as well as some pitfalls Rate this link
- Hardware Implementations of Multirate Digital Filters - sometimes it is important to map interpolation and decimation functions directly into hardware Rate this link
- Introduction to DSP - first module of the BORES Signal Processing DSP course - Introduction to DSP Rate this link
- Introduction to DSP MIPS, MOPS and Mflops Rate this link
- IRCAM Scientific and Musical Articles - acoustics articles Rate this link
- Liquid Systems Group DSL Links - a good DSP links collection Rate this link
- Multimedia instructions boost host-based processing - Traditional CPUs have been enhanced with multimedia instructions to perform parallel processing suitable for DSP applications. Multimedia instructions capitalize on a CPU?s capability to perform parallel processing. You can take advantage of these instructions to increase the performance and functionality of your application. Rate this link
- Poynton's Digital Signal Processing Resource List - FIR Filter Design Software Rate this link
- RTOSs simplify DSP-application development and debugging - DSPs are finding increasing applicability in consumer electronics and automotive electronics, along with their traditional telecommunications applications. Unfortunately, design tools for DSPs have not kept pace with their growing popularity. RTOSs from a few vendors are addressing this issue. Rate this link
- Soft Radios and Modems on FPGAs - FPGA is now competing with DSP chips for soft radio and modem design Rate this link
- Software-development tools are growing up - As processors become more powerful, more people without traditional programming backgrounds are developing embedded systems. Evolving software-development tools make this situation possible. Rate this link
- Stephen M. Sprenger's Audio DSP Pages - educational, strictly non-commercial and useful DSP website Rate this link
- The alias theorems: practical undersampling for expert engineers - Aliasing, long considered an undesirable artifact of an insufficiently high sampling rate, is in fact a useful tool for lab testing and analysis. Rate this link
- The Scientist and Engineer's Guide to Digital Signal Processing - web site of the book, includes some chapters from the book about filtering, spectral analysis and data compression, also DSP programs and files Rate this link
- Tools of the trade: successful DSP-software development and testing - Using tested principles and design methodologies, you can create reliable, easy-to-integrate, easy-to-support, and high-quality code with a long life cycle. The resulting C code is platform-independent and reusable with standardized interfaces. Rate this link
- Using VHDL-AMS to model complex heterogeneous systems, part 2 - You can implement DSP-controller algorithms using the mixed-signal features of the VHDL-AMS modeling language. Rate this link
General information links
- Audio file formats FAQ - This directory contains various documents and programs having to do with sound. The Audio File Format FAQ is a collection of information related to Sound Formats used by computers that was started in November of 1991 by Guido van Rossum. Rate this link
- Audio File Format FAQ - This document has technical specs of different common audio formats. The Audio File Format FAQ is a collection of information related to Sound Formats used by computers that was started in November of 1991 by Guido van Rossum. Rate this link
- SoX - Sound eXchange - the swiss army knife of sound processing programs Rate this link
- The Canonical WAVE File Format Rate this link
File formats
- Adaptyv DSP links - lots of signal processing links Rate this link
- Analog Devices Virtual Design Center - lots of DSP related application notes Rate this link
- TechOnLine DSPnet - digital signal processing resources, image processing, technology mall Rate this link
- Ebox: DSP Internet Resources Rate this link
- Electronic Engineers' Toolbox - Embedded Systems, DSP, Real-Time Computing and Industrial Computing Rate this link
Link and resource pages
- Advanced VLIW Architectures Unleash Raw DSP Horsepower - a new wave of DSPs boasts a tenfold improvement in signal processing while slashing power to a new low Rate this link
- Audio DSP provides flexible serial I/O - you can easily program DSP controller various serial inputs and outputs to provide other application-specific inputs and outputs, as well as simple repetitive signals, such as convert or frame-synchronization Rate this link
- DSP Processor Overviews - brief description of large number of signal processors Rate this link
- Texas Instruments Application Reports - interfacing to signal processors Rate this link
Signal Processors
- Alef Null DSP CARD 4 - Alef Null is a group of amateurs in Finland who have been active in the development of DSP projects since 1992. The DSP CARD 4 is their fouth generation DSP Card. It utilizies the Motorola DSP56001 DSP chip. Rate this link
- Electronics companies which make DSP modules Rate this link
DSP Cards
- Digital Filters: An Introduction - This tutorial is a good, in-depth, yet easy to understand, explanation of digital filters. It includes digital filters' advantages, types, parameters, and it also has examples of simple filters. The site is HTML and the tutorial is also available as a PDF file. Rate this link
- DSP algorithm measures frequency and damping Rate this link
- DSP Design Performance - site which contains a set of Java applets which may be freely used to design digital filters of many types, including high-Q notch filters, fractional-sample time delay filters and comb filters, in addition to the more traditional low-pass, high-pass, band-pass and band-stop filters, differentiators and Hilbert transformers Rate this link
- DSP filters tutorials, examples, overviews Rate this link
- Introduction to Signal Processing - book web page with the example source codes available on-line Rate this link
- Numerical Recipes in C book On-Line! Rate this link
- Real-Time Versus Equivalent-Time Sampling - sampling in digital storage oscilloscopes and sin(x)/x interpolation Rate this link
- Scrub data with scale-invariant nonlinear digital filters - Simple linear digital filters are useful in many applications, but they have some limitations. The idea may be counterintuitive, but for a large class of filtering tasks, nonlinear filters can preserve signal fidelity better than their linear cousins. Rate this link
- Spice does digital filters - you can use Spice to simulate digital or discrete time filters as well as analog or continuous time filters Rate this link
- How Dolby Stereo (aka Dolby Surround) works Rate this link
- A bit about reverb - Reverb is one of the most interesting aspects of digital signal processing effects for audio. It is a form of processing that is well-suited to digital processing, while being completely impractical with analog electronics. Rate this link
- Acoustical Modeling Publications and Software by Julius Orion Smith III Rate this link
- Active Noise Control FAQ Rate this link
- Advances in Speech Enhancement on Voice-over-IP Applications - number of speech quality impairments within VoIP networks threaten the ability to provide comparable quality to a circuit-switched network Rate this link
- Introduction to Noise Removal Rate this link
- Asynchronous conversion thwarts incompatibility in sampling A/D systems - By using asynchronous sample-rate conversion, you can eliminate the problem of repeated or dropped samples that can occur when interconnecting systems with incompatible clock rates Rate this link
- Companding systems used in telephone PCM systems - A-law and mu-law explained Rate this link
- Computer speech compression techniques - comp.speech.FAQ, speech data, software Rate this link
- DSP Solutions for Data/Facsimile Modems - application note from Texas Instruments Rate this link
- Expanding options bring surround sound to the forefront...and the back... and the sides...and the ceiling...and the floor... - Why make your potential customers travel to movie theaters, performance halls, and video arcades to enjoy surround sound? Ever-evolving technology, in conjunction with DSPs and memory, create an immersive audio experience no matter where you hear it. Rate this link
- FIR filter Design by Windowing Rate this link
- GSM 06.10 lossy speech compression Rate this link
- Guitar Effects FAQ Rate this link
- Harmony Central Effects Resources Rate this link
- How Dolby Stereo (aka Dolby Surround) works - and how to make your own surround sounds using your soundcard Rate this link
- How Vocoders Work Rate this link
- Implementation of a High-Quality Dolby Digital Decoder Using MMX Technology - includes basic introduction to Dolby Digital decoding Rate this link
- Introduction to Digital Filters - introductory chapter from a book Rate this link
- Introduction to Signal Processing book page - book discusses algorithms for digital audio effects, this pages has all code found in the book! Rate this link
- Mathtools.net Java Filtering - filter design applications Rate this link
- Modulation and Delay Line Based Digital Audio Effects - In the field of musicians and recording engineers audio effects are mainly described and indicated by their acoustical effect. Audio effects can also be categorized from a technical point of view. The main criterion is found to be the type of modulation technique used to achieve the effect. After a short introduction to the different modulation types, three more sophisticated audio effect applications are presented, namely single sideband domain vibrato (mechanical vibrato bar simulation), a rotary speaker simulation, and an enhanced pitch transposing scheme. Rate this link
- Notch filter uses only lowpass filters - describes textbook method and one simpler method Rate this link
- Practical use of the Hilbert Transformation - application note from Rate this link
- Sampled sound processors - information on delay, pitch change, reverberation and digital filters Rate this link
- Speech Coding - principles involved in speech coding and details of commonly used coders Rate this link
- Time/Pitch Scaling FAQ/References Page - how to pitch of a signal without changing its length Rate this link
- A Real Time 3D Signal Analysis/Synthesis Tool Based on the Short Time Fourier Transform Rate this link
- Evaluation of several DTMF decoding algorithms - subspace, adaptive and DFT Rate this link
- Old measurements, new techniques: DSP drives speed and accuracy; coherence saves the day - DSP techniques lead to faster, less costly frequency-response tests and enable the use of a powerful concept, the coherence function, which acts as a watchdog to help identify and quantify common but easy-to-miss measurement errors. Best of all, this watchdog works for free. Rate this link
- Ratio detection precisely characterizes signals' amplitude and frequency - straightforward models of how humans perceive sound and color lead to amazingly simple techniques that use Gaussian filters and ratio detectors to extract signals' information content Rate this link
- Spectral Analysis of Signals Rate this link
- Array Processors Enable Flexibility in FFT Designs - Reconfigurable processors allow designers to implement FFT architectures in OFDM-based comm systems that can adapt to changing standards. Rate this link
- Data Compression - introductory chapter from a book Rate this link
- Image resizing and enhanced digital video compression - image resizing and image compression are playing an important role in improving the quality of video images Rate this link
- JPEG image compression FAQ - read also Rate this link
- JPEG parameters determine compression-system performance - The wide availability of JPEG software and hardware simplifies image-compression system design. Before using the equipment, you must resolve quantization table design and system performance. Rate this link
- Off-the-shelf components make light work of machine vision - Making systems recognise objects and their properties is central to many of today?s automated processes. Once the domain of artificial-intelligence experts, vision systems and software packages enable industrial-strength applications in minimal time and without specialist knowledge. Rate this link
- Software-based PAL colour decoding - This page explains the issues concerning the decoding of colour from broadcast-standard television pictures, and presents software algorithms and a Windows-based application capable of colourising PAL-encoded still-frame images with very high quality. This is an interesting project in practical image-processing! Rate this link
- Stereo vision based mapping and navigation for mobile robots Rate this link
- The implementation of the IDCT by means of the IDFT Rate this link
- Tomi Engdahl's computer graphics web page - very many useful links to computer graphics information Rate this link
- Carrier Sychronization For DSP-Based Modems Rate this link
- DSP Solutions for Data/Facsimile Modems - application note from Texas Instruments Rate this link
- DTMF Tone Generation and Detection: An Implementation Using the TMS320C54x - This application note describes the implementation of a dual tone multiple frequency (DTMF) tone generator and detector for the TMS320C54x. This application note provides some theoretical background on the algorithms used for tone generation and detection. It documents the actual implementation in detail. Rate this link
- Eliminate Signal Noise With Discrete Wavelet Transformation - Modern DSP and communications applications are beginning to use wavelet transforms in critical algorithms Rate this link
- Evaluation of several DTMF decoding algorithms - subspace, adaptive and DFT Rate this link
- Wavelet Digest - free monthly newsletter of information concerning wavelets Rate this link
- Wavelets both implode and explode images - Wavelet video-processing technology offers some alluring features, including high compression ratios and eye-pleasing enlargements. Rate this link
- Wavelets Internet Sources Rate this link
Algorithms and theory
Fourie transform (in the form of FFT) is a very commonly used technique for analyzing and filtering digital signals. FFT is not very optimal in many filtering applications because it assumes that the frequency spectrum is not changing over time. There are other digital-signal-processing (DSP) techniques that are more advantageous for filtering a real-world signal. Theinfinite-impulse-response (IIR) and finite-impulse-response (FIR) filters can be implemented very inexpensively, and they work on continuous stream of data. The wavelet transform is worth investigating new technique for signal analyzing and filtering. Like the FFT, wavelet transform converts time-domain data into the frequency domain. The wavelet transform assumes that the frequency spectrum is changing over time. The result of a wavelet transform is a bit harder to read, but more meaningful for many applications.There are also many other relevant signal processing techniques targetedfor different kind of applications.
General
Audio
Signal analysing
Image and video
Telecommunications
Wavelet
- GSM 06.10 lossy speech compression - encoder and decoder software for many computer platforms Rate this link
- KC7WW's Collection of Utilities and Application Package for the DSP56002EVM Rate this link
- Common Music - Common Music (CM) is an object-oriented music composition environment. It produces sound by transforming a high-level representation of musical structure into a variety of control protocols for sound synthesis and display. Common Music defines an extensive library of compositional tools and an API through which the composer can easily modify and extend the system. This is a music synthesis and signal processing package written primarily in Common Lisp. Rate this link
- Sound Processing Kit - object-oriented class library for audio signal processing implemented in C++ Rate this link
- FFTPACK library - makes conversion to arbitary length data Rate this link
- FFTW - C subroutine library for performing the Discrete Fourier Transform (DFT) in one or more dimensions Rate this link
- CCITT-ADPCM codec source codes Rate this link
- Source code for the G.72x codecs Rate this link
- Source code for audio codecs in C - ADPCM, G.72x, LPC, GSM, CELP Rate this link
Software and source code
Utilities
Sound libraries
FFT
Using the fast-Fourier transform (FFT) is one of the most popular ways to convert a series of digital samples from the time domain to the frequency domain. The result of an FFT looks like the output of a spectrum analyzer. The FFT works in both directions, converting signals from time domain to frequency domain and form frequency domain to time domain. FFT can be used for exmaple to analyze or digitally filter a signal. The FFT assumes that the spectrum does not change over time, which makes it not very ideal for filtering real-world signals.
Audio codecs
Misc routines
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