DDS Basics (EE Tip #122)

Figure 1: The most basic digital signal generator is built with a simple binary counter. Its output sequentially
addresses the rows of a memory, which holds the successive points of the output signal. It is then converted to an
analog signal and filtered.

The simplest form of a digital waveform synthesizer is a table look-up generator (see Figure 1). Just program a period of the desired waveform in a digital memory (Why not an EPROM for old timers?), connect a binary counter to … Continue reading


Using Arduino for Prototypes (EE Tip #121)


Arduino is an open-source development kit with a cult following. Open source means the software and hardware design files are available for free download. This begs the question of how the Arduino team can turn a profit, and the answer … Continue reading


Basic Goertzel (EE Tip #120)

Figure 1: 
Figure 1—The signal flow of the basic Goertzel transform produces an output (y0) for each sample processed. The output is a combination of the current ADC sample added to the product of the previous output (y1) multiplied by a constant minus the previous output (y2). After a block of samples has been processed, the sum of the squares of y1 and y2 are computed to determine the relative amplitude of a particular frequency.

The basic Goertzel transform, which has been around since 1958, was derived from the discrete Fourier transform (DFT). It’s an extremely efficient method of detecting a single frequency component in a block of input data. Figure 1 depicts the signal … Continue reading


IR Remote Control Testing (EE Tip #119)

IR remote tester

On the Internet you can find them in all shapes and sizes: circuits to test remote controls. Here I describe a simple and cheap method that is not that well-known. This method is based on the principle that an LED … Continue reading


Desoldering Components (EE Tip #118)

Desoldering components from a printed circuit board.

Every engineer and technician sooner or later faces the challenge of having to desolder a component. Sometimes the component can be a large transformer with 10 pins or a power chip with many connections, and desoldering tools are typically around … Continue reading


Arduino-Based DIY Voltage Booster (EE Tip #117)

Source: Elektor, April 2010

If your project needs a higher voltage rail than is already available in the circuit, you can use an off-the-shelf step-up device. But when you want a variable output voltage, it’s less easy to find a ready-made IC. However, it’s … Continue reading


Circuit Protection (EE TIP #116)

Figure 1

Circuit protection is necessary to ensure that a circuit will work reliably for 10 years and beyond. Input power supplies are susceptible to spikes from various sources including lightning, high-power machinery (e.g., generators and motors), or interference from outside sources … Continue reading


Electromagnetic Compliance Protection (EE TIP #115)

EMC Protection

Electromagnetic compatibility (EMC) compliance is one of the last processes before a device may be released to the public. EMC goes hand-in-hand with electromagnetic immunity (EMI), but immunity is only needed for critical devices. With EMC, it is very important … Continue reading


Open-Source Guide for Embedded Systems Developers (EE Tip #114)


What comes to mind when you hear the term “open source”? Hopefully, it means more to you than just a software application running on a PC. As an embedded systems developer, you should familiarize yourself with the wide range of … Continue reading


PCB Design Guidelines (EE Tips #113)


Designing a matching printed circuit board (PCB) can be a challenge for many electronics enthusiasts. To help ease the process, Circuit Cellar and Elektor editors compiled a list of tips for laying out components, routing, and more. When compactness is not … Continue reading


Testing Power Supplies (EE Tip #112)

Power supply testing

How can you determine the stability of your lab or bench-top supply? You can get a good impression of the stability of a power supply under various conditions by loading the output dynamically. This can be implemented using just a … Continue reading


Prototyping for Engineers (EE Tip #111)


Prototyping is an essential part of engineering. Whether you’re working on a complicated embedded system or a simple blinking LED project, building a prototype can save you a lot of time, money, and hassle in the long run. You can … Continue reading


DSP vs. RISC Processors (EE Tip #110)


There are a few fundamental differences between DSP and RISC processors. One difference has to do with arithmetic. In the analog domain, saturation, or clipping, isn’t recommended. But it generally comes with a design when, for example, an op-amp is driven … Continue reading


Reduce EMI on a Micro (EE Tip #109)


Electromagnetic interference (EMI) on a typical microprocessor board is related to the clock. If the clock is a square wave, it contains frequencies at the clock frequency and harmonics. A perfect square wave clock would have harmonic frequencies at f, … Continue reading


Toroid Cutting Simplified (EE Tip #108)


Need to work with a toroidal coil? The following toroid-cutting tips will help you prep for circuit deployment. First, pick the correct ferrite toroid for your application, put the windings on, and secure it in a vise (do not over tighten). Consider … Continue reading