## DSP Central

dspGuru provides a wide variety of DSP information to help you master the complex domain of Digital Signal Processing, including:

• FAQs:  At last, Frequently Asked Questions about DSP meet up with Rarely Given Answers, in a friendly, tutorial format.
• Tutorials: Primary DSP subjects made simple.
• HowTos: Here we divulge the secret "Tribal Knowledge" of DSP - stuff that experienced DSP'ers know, but isn't in the textbooks. (Don't tell anybody!)
• Tricks:  Algorithmic and design tricks that make your life in DSP a little easier.
• Books:  Which of a zillion DSP books should you add to your personal DSP library?  To help you choose, we provide listings of DSP books organized in a wide variety of ways.
• Links:  There's gotta be something we haven't covered, so we provide a comprehensive set of links to other DSP resources on the Internet.
• Reference: Handy information to refer to.
• comp.dsp: Got questions? Usenet's DSP newsgroup has answers.

dspGuru is and always has been a community effort.  Here's how you can help:

## Convolution: A Visual Digital Signal Processing Tutorial

Understanding convolution is central to understanding filtering, the Discrete Fourier Transform, and other important DSP operations.  In this tutorial, R. C. Kim explains convolution using a visual, intuitive, step-by-step method, and relates it to filtering and the DFT.

## Reducing FFT Scalloping Loss Errors Without Multiplication

In this tutorial, Richard G. Lyons, author of the best-selling DSP book Understanding Digital Signal Processing, discusses the estimation of time-domain sinewave peak amplitudes based on fast Fourier transform (FFT) data.

## Multipath Channel Model Using DSP

Multipath distortion is a common problem in many DSP-based data transmission systems.  Here, Neil Robertson shows how to model multipath channels using complex-coefficient FIR filters.

## Sum of Two Sinusoidal Functions

Many DSP systems use composite signals consisting of a sum of sinusoids of the same frequency, often a sine and cosine. In this tutorial, Richard G. Lyons, author of the best-selling DSP book Understanding Digital Signal Processing, thoroughly covers this important DSP topic by explaining and deriving formulas for the sum of two sinusoids of the same frequency.

## PowerWalkers (TM): Saving the Environment One Step at a Time

Readers of my previous blog entry "What Light Through Yonder Flashlight Shakes?" have asked for details about the science project that caused my son and I to look into shake flashlights in the first place. Here goes.

## What Light Through Yonder Flashlight Shakes?

I recently helped a lad put together a school science project that involved the idea of using "shake flashlights" as a power source.  The idea seemed like a good one when he first proposed it.  But when we began to implement it we immediately ran into a quite unexpected problem: it's impossible to find shake flashlights in retail stores.

## Of all the Gall

I ran into Gall's Law recently, which states: "A complex system that works is invariably found to have evolved from a simple system that worked. The inverse proposition also appears to be true: A complex system designed from scratch never works and cannot be made to work. You have to start over, beginning with a working simple system."