The following links though not comprehensive, outline resources available for scientist and engineers with varying levels of knowledge in the field of digital signal processing (DSP), access to some of the resources may require user registration:

• A beginner's guide to digital signal processing

  The links below provide introductory information aimed at readers with little or no experience of signal processing in general or digital signal processing in particular. The first link is to the Wikipedia entry on DSP, which itself links to further resources. These act as a good general introduction to DSP.
  
  
  • Digital signal processing: Wikipedia link
  • An Intuitive Approach to DSP: a free on-line DSP training course from Texas Instruments.
  • The Scientist and Engineer's Guide to Digital Signal Processing (eBook): can be browsed on-line or downloaded free of charge in .pdf format.
  • Java digital signal processing (J-DSP) Editor: Internet based signal processing laboratory developed at Arizona State University. Can be used to simulate simple DSP systems.
  • DSP dictionary: simple definitions of some basic signal processing terms.
  • Three DSP Tips: some advice on dealing with signals with very poor signal-to-noise ratios.
  • Why Use DSP?: introduction to DSP system design published by Analog Devices.
  • Part I: Fourier transforms and sampling: part of a cyber book written by Arthur Ludwig, a retired engineer from the NASA Jet Propulsion Lab. The book mainly deals with acoustics applications but has a section on signal processing and filters, to which this link connects.
  • Signal processing preliminaries: a brief PowerPoint introduction to signal processing from the October 2004 graduate school of the International Conference on Music Information Retrieval.
  • <!-- Download server -->Algorithms, applications and systems for digital signal processing: overview of real time DSP systems from the NPL signal processing seminar, November 2005.
  • Tutorials: links to advice on a range of DSP topics from the Maxim Integrated Products and Dallas Semiconductor web pages.
  • Resources for EEducation: more from the Maxim Integrated Products and Dallas Semiconductor web pages, this time aimed at teachers and students.
  
  

• Hardware and firmware in DSP, DSP chips

  This section provides a portal to hardware manufacturers:
  
  
  • TechOnline: Electronics company directory
  
  This section sets out links to advice on hardware requirements for DSP.
  
  
  • Digital signal processing: from the Electronics Design Network (EDN), which is the successor to DTI's Electronics Design Programme which ended in March 2004. The Network comprises the four design consultancies and the eight universities that resourced the Electronics Design Programme.
  • Choosing a DSP processor: a brief guide from Berkeley Design Technology Inc. Dates from 1999-2000.
  • The evolution of DSP processors: another short guide from Berkeley Design Technology Inc.
  • Mixed Signal and DSP Design Techniques: on-line book from Analog Devices.
  • Processor overviews: processor architectures and performance specifications from Berkeley Design Technology Inc.
  • DSP 101 Part 3: Implement Algorithms on a Hardware Platform: more from Analog Devices.
  • Onboard signal processing (OSP) on National Instruments signal generators.
  • Data converters: characterisation and optimisation: download talks from the summer 2006 DC & LF club meeting at NPL.
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  • Data converters: technologies, limitations and performance improvement: Manchester University lecture notes by Dimitrios Georgakopoulos of NPL's DC & LF group.
  
  

• DSP-related software tools

  • Code composer studio (CCStudio) development tools: DSP application development for multi-processor, multi-user and multi-projects from Texas Instruments.
  • VisualDSP++: An integrated software development and debugging environment from Analog devices.
  • MATLAB signal processing toolbox: This is collection of industry standard alogorithm for analog and digital signal processing from The MathWorks.
  • LabVIEW: National Instruments development system.
  • Mathematica Signals and Systems: This is a collection of functions which can be used in analysing signals, designing filters, etc from Wolfram Research.
  • General DSP development software from Momentum Data Systems.
  • DSP Builder: A DSP development tool that interfaces between Quartus II software and The MathWorks MATLAB/Simulink tools from Altera.
  
  

• Analogue signal conditioning and processing

  • Data Acquisition: The Elements of Intelligent Design: brief introduction to the process of data acquisition from CyberResearch - discusses the whole process from the physical system to the transducer and to the signal conditioning circuits prior to the delivery of the signal to the analogue-to-digital converter.
  • Signal conditioning: more from CyberResearch on signal conditioning.
  • Basics of measurement technology: short introduction to measurements and signal conditioning from 2D Debus & Diebold Meßsysteme GmbH.
  • Principles of analog signal conditioning: from National Instruments' NI Developer Zone.
  • Analogue signal conditioning and effective programming for processing large volumes of data: paper on data logging from physics department of the University of Otago, New Zealand.
  • Signal conditioning fundamentals for computer-based data acquisition systems:from National Instruments' NI Developer Zone.
  
  

• Analogue to digital: the sampling and quantisation process

  This section sets out links to advice on how to choose sampling frequencies so that all the required information in the signal is captured.
  
  
  • Nyquist/Shannon sampling theorem: fundamental theorem in information processing - this links to the relevant Wikipedia pages.
  • Sampling: from Fundamentals of Mixed Signal Processing by Soft Test, who provide courses in test technology for the semiconductor and automated test equipment industries.
  • An Introduction to the Sampling Theorem: application note from National Semiconductor, published in 1980 but still relevant.
  • Control Dynamic Range: note from LDS Test and Measurement that discusses quantisation and digitisation of signals with a wide dynamic range.
  • Sampling and Reconstruction of Periodic Signals: from the on-line magazime of DSP-FPGA.com, previously the DSP Engineering magazine.
  • Synchronization of sampling in distributed signal processing systems: paper on real-time data acquisition in networks of intelligent sensors from the Department of Measurement and Information Systems, Budapest University of Technology and Economics.
  • Coherent sampling vs Window sampling: from the Maxim Integrated Products and Dallas Semiconductor web pages, advice on sampling merthods especially for evaluating the dynamic performance of high-speed analog-to-digital converters.
  
  

• Processing in real time and processing off-line

  Some resources on real-time processing, often linked to specific applications.
  
  
  • Real-Time DSP Data Acquisition System: general article reveiwing some relrvant issues from the Sound and Vibration magazine web site.
  • A Software Definable MIMO Testbed: Architecture and Functionality: paper presented at the 2005 Annual Postgraduate Symposium on Convergence of Telecommunications, Networking and Broadcasting at Liverpool John Moores University.
  • Programming Considerations for Real-time I/O: from Analog Dialogue, the technical magazine from Analog Devices, extract from their on-line course DSP 101.
  • Classical low-pass filter and real-time wavelet-based denoising technique implemented on a DSP: a comparison study: Dolabdjian et al, European Journal of Physics Applied Physics 20 (2002) pp 135-140, real-time denoising applied to an electrocardiogram signal.
  
  

• Time domain versus frequency domain processing

  • Filtering in the Frequency Domain: from the Connexions web site, a collaborative project to make available free educational material and software.
  • A Time-Domain-Based Technique for Noise Measurements: short article from TechOnline.
  • Frequency Domain Theory: introduction to frequency domain signal processing from TechOnline.
  • Advanced concepts in time-frequency signal processing made simple: brief introduction to time-frequency analysis in paper presented at 2003 USA Frontiers in Education conference.
  • <!-- Download server -->Pulses and parameters in the time and frequency domains: overview from the NPL signal processing seminar, November 2005.
  
  

• Understanding the Fourier transform from continuous FT to DFT to FFT

  The Fourier Transform is the basic signal processing tool for identifying the frequency content of signals. Understanding its use and its limitations is the key to a wide range of signal processing applications.
  
  
  • The Fundamentals of FFT-Based Signal Analysis and Measurement: application note from TechOnline.
  • Spectrum Analysis Using the Discrete Fourier Transform: more from the Connexions web site, a collaborative project to make available free educational material and software.
  • Mixed Signal and DSP Design Techniques: more from Analog Devices on-line books.
  • This site hosts information on FFTW which is a free C library (developed at MIT) used for computing discrete Fourier transform (DFT) in one or more dimensions. The" Fastest Fourier Transform in the West" won the 1999 Wilkinson Prize for Numerical Software.
  • Notes on Fourier analysis: The basics and beyond: short note on Fourier methods from the Prosig web site, which offers free signal processing tutorials.
  • Mathematics of the Discrete Fourier Transform (DFT): on-line version of book by academic from Stanford University's Department of Music.
  • FFT Accuracy Benchmark Comments: a few comments on why certain FFT routines are more accurate than others.
  
  

• Aliasing

  • The Basics of Anti-Aliasing: Using Switched-Capacitor Filters: application note from the Maxim Integrated Products and Dallas Semiconductor web pages giving advice on anti-aliasing filters.
  • Analog and Digital Filtering for Anti-Aliasing: simple introduction to practical effects of aliasing and how to avoid them from Microstar Laboratories.
  • Industrial signal conditioning, a tutorial: practical advice from Dataforth; includes advice on anti-aliasing.
  • Tutorial: basics of choosing and designing the best filter for an effective data-acquisition system: TechOnline article emphasising the importance of analogue filters for anti-aliasing purposes.
  
  

• Windowing

  Many aspects of windowing are covered in resources that have been identified in other sections of this lists. However, further specific links are given below.
  
  
  • Wikipedia pages on window functions
  • Frequency Domain Theory: TechOnline resources that require registration prior to access.
  
  

• Correlation and convolution

  • Convolution: digital signal processing: application note from National Semiconductor.
  • Signal processing in processing: convolution and filtering: short article from the Connexions project.
  
  

• Spectrum estimation and analysis

  • Wikipedia pages on the periodogram, an important tool for calculating power spectral density
  • Wikipedia pages on spectral density
  
  

• Noise and interference

  • Cleaning up data: Using a median filter to remove spikes from data: practical advice from the Prosig web site on the use of median filters for noise removal.
  • Noise and signal processing: notes from University of Leiden third year signal processing course.
  
  

• Designing filters

  • Introduction to digital filters:on-line version of book by academic from Stanford University's Department of Music.
  • Digital filter terminology: from a book by R. G. Lyons, Understanding Digital Signal Processing, 1997, Addison Wesley Longman.
  • Analog filter design demystified: application note from the Maxim Integrated Products and Dallas Semiconductor web pages.
  • A filter primer: another application note Maxim Integrated Products and Dallas Semiconductor.
  • Analysis of the Sallen-Key architecture: application report from Texas Instruments on this popular filter architecture.
  • Practical FIR filter design in MATLAB: from Mathworks' Matlab Central Exchange (often a good source of m-files for Matlab applications).
  • Design of IIR filters with a given 3 dB point: from Mathworks' Matlab Central Exchange.
  • Digital filter design guide: short practical application note from Frequency Devices Inc.
  • Analog and digital filter design guide: more from Frequency Devices Inc.
  • Why use DSP?: Digital Signal Processing 101-an introductory Course in DSP System Design-Part 2: on-line course from Analog Dialogue.
  • A basic introduction to filters - active, passive, and switched-capacitor: application note from National Semiconductor.
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  • Good practice in signal processing: a simple introduction to filters:
  • FilterLab design software: free filter design software from Microchip.
  • FilterCAD: filter design software from Linear Technology.
  
  

• Nonstationary signals and how to analyse them, including wavelet resources

  • Time-frequency signal processing: a statistical perspective: Invited paper by Franz Hlawatsch and Gerald Matz, Vienna University of Technology, at the IEEE Workshop on Circuits, Systems and Signal Processing (CSSP98), Mierlo, Netherlands, 1998.
  • Robuston methods for stable statistical signal processing principles and application to nonstationary signal estimation:paper by Franz Hlawatsch, Gerald Matz, and Michael Jachan, Vienna University of Technology at IEEE ICASSP-03 conference, Hong Kong, April 2003.
  • Advanced processing of nonuniformly sampled non-stationary signals: paper by M Greitans, University of Latvia, published in "ELECTRONIKA IR ELECTROTECHNIKA", Nr 3 (59) 2005.
  • An Introduction to Wavelets: from the personal web pages of the astronomer, Amara Graps. A pdf version can be downloaded.
  • A Really Friendly Guide to Wavelets: from TechOnline. You will need to register on the site to download the pdf.
  • Wavelets: A New Tool for Signal Analysis: more from TechOnline.
  • Emerging Applications of Multirate Signal Processing and Wavelets in Digital Communications: paper by Gregory Wornell in Proceedings of the IEEE, 84(4), April 1996.
  • A Practical Guide to Wavelet Analysis: an article by Christopher Torrence and Gilbert Compo from the Bulletin of the American Meteorological Society, 1998, that includes discussion of statistical significance tests for wavelet power spectra.
  • Preview of Wavelets, Wavelet Filters and Wavelet Transforms: from Conceptual Wavelets in Digital Signal Processing by D. Lee Fugal.
  • Wavelets and Signal Processing: from personal web pages of Ian Kaplan.
  • The Wavelet Transform: from the personal web pages of Clemens Valens.
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  • The application of wavelets and other techniques to the calibration of underwater electroacoustic transducers in reverberant laboratory tanks: NPL Report that can be downloaded from the NPL web site.
  • An introduction to the analysis of non-repetitive signals using joint time-frequency distributions and wavelets: presentation by Paul Wright of NPL's DC & LF group.
  • Signal conditioning in acoustic emission analysis using wavelets: from NDT.net, the e-Journal of Nondestructive Testing.
  • On the Space of Orthonormal Wavelets: paper by B.G. Sherlock and D.M. Monro, IEEE Transactions on Signal Processing, June 1998, Vol. 46, No. 6, pp. 1716-1720.
  • Space-Frequency Balance in Biorthogonal Wavelets: paper by D.M. Monro and B.G. Sherlock, Proc. IEEE ICIP 1997, Vol. 1, pp. 624-627.
  • Optimized wavelets for fingerprint compression: paper by Sherlock, B.G. and Monro, D.M., Proc. IEEE ICASSP 1996, Vol. 3, pp. 1447-1450.
  • Orthonormal Wavelets With Balanced Uncertainty: paper by Monro, D.M., Bassil, B.E. and Dickson, G.J., Proc. IEEE ICIP 1996, Vol. 2, pp. 581-584.
  • Psychovisually Tuned Wavelet Fingerprint Compression: paper by Sherlock, B.G. and Monro, D.M., Proc. IEEE ICIP 1996, Vol. 2, pp. 585-588.
  
  

• Uncertainty budgets and signal processing

  • Fundamental limits on detection in low SNR under noise uncertainty: paper by Rahul Tandra and Anant Sahai of the Department of Electrical and Computer Science, University of California, Berkeley.
  • Optimal Speech Enhancement Under Signal Presence Uncertainty Using Log-spectral Amplitude Estimator: short paper by Israel Cohen of Lamar Signal Processing Ltd.
  • Current state and trends of ensuring traceability for vibration and shock measurements: paper by Hans-Jürgen von Martens in Metrologia, 1999, 36, pp 357-373.
  • Calibration methods for vibration transducers and their uncertainties: paper by T. Usada and T. Kurosawa in Metrologia, 1999, 36, pp 375-383.

• Some additional useful links from Wikipedia

  • Time-frequency representation
  • Wavelets
  • Digital filters
  • Noise in various physical systems and interference
  • Autocorrelation
  • Correlation
  • Convolution and deconvolution
  • Aliasing