The HebrewSecurImage Captcha generator

Introduction Do you recognize the letters in the example image above? If you do, I suppose you’re a Hebrew speaker. And since the letters are shown in handwriting style, just a Hebrew keyboard is not enough, since the keys are marked with type-style letters. With basic Hebrew skills, the translation is obvious. Others will have [...]

FPGA Editor video tutorial

Having made several FPGA projects for my clients, I’ve learned that most of them are reluctant to use the Xilinx FPGA Editor. While most seem to realize that’s it’s a valuable tool, few really grasp the enormous advantage it offers, in particular when debugging FPGA designs: The possibilities to view the FPGA down to the [...]

hitec: Document style for engineers’ papers in LaTeX

I love LaTeX. It’s my preferred tool whenever I need to write a document in English. But it had one little problem: The documents it generated, even though beautifully typeset, had an academic look. For someone who submits the documents to hitec companies, an engineering-like look was more appealing. So I wrote my own document [...]

peakdet: Peak detection using MATLAB (non-derivative local extremum, maximum, minimum)

Here’s a problem I encounter in several fields: Find the local maxima and minima in some noisy signal, which typically looks like the following graph: The local maxima and minima are plotted as red and green stars on the graph. To the eye it’s so obvious where they are, but making a computer find them [...]

easyspec: A spectrum-analyzer like plotter for MATLAB

I’m using MATLAB since about 1992. One of the things that I’ve always missed, as a communication engineer, is a quick and dirty spectrum plot of signals. I want to see what the spectrum analyzer will show me when I’ll run the signal through it, and not some analytic plot, which looks nothing like. The [...]


Introduction 2022 update: This is probably quite pointless today, but that’s not reason enough to delete this post. cdepend is a cross-reference utility, whose main purpose is mapping which function calls which in a C language project. As projects grow and develop, it becomes harder and harder to keep track of which functions are actually [...]


Frandom is a Linux kernel random number generator, which is 10-50 times faster than what you get from Linux’ built-in /dev/urandom. And it uses very little (/dev/frandom) or none (/dev/erandom) of the kernel’s entropy pool, so it is very useful for applications that require a handy source for lots of random data. Its most common [...]

Eobj: Environment for Easy Object Oriented (OO) programming in Perl

Eobj is a Perl programming environment. Well, technically speaking, it’s a Perl module. Eobj stands for Easy Objects. Idea: Object oriented programming is supported very well in Perl, but it requires some rather advanced programming techniques: Perl modules and namespaces, references, blessings and some syntactic sugars. In addition, the awareness of some special variables is [...]

Verilog FPGA module for programming CDCE906/CDCE706/CDC906/CDC706 clock synthesizer over SMBus/I2C/IIC

Somewhere in 2006 TI (Texas Instruments) released a clock synthesizer, CDCE906, which is pretty much everything one can look for in a system clock generator: Several (up to 6) clock outputs derived from a single reference clock or crystal with excellent multiplication and division capabilities, not to mention low jitter, slew rate control, spread spectrum [...]


Perlilog is a command-line tool which generates Verilog modules from a set of files, which come in several other formats. It was originally designed to integrate Verilog IP cores. It’s released as free software (GPL). Motivation: Anyone who has needed to integrate a few Verilog modules into something working, knows it’s a headache. It’s not [...]