Master the Radio Arts
In this next series of posts, we’re going to dive into the heart of the radio arts: modulation. Modulation is what make wireless communications possible. Over the years, many different ways to modulate signals have been created. The advent of digital electronics has brought along with it a slew of new digital modulation techniques as … Read more
When studying amplifiers it’s impossible to leave out the differential amplifier. It is a very common and well known building block in electronics, and is also the basis for one of the most popular RF mixers: the Gilbert Cell mixers. Learning about the differential amplifier won’t just give you a useful tool in your electronic … Read more
Our first post on mixers focused on essential mixer theory and passive mixers. Understanding the diode double-balanced mixer is a great start, but that still leaves many mixer architectures unexplored. Some of the most popular mixers used in to today’s commercial and amateur gear are active mixers, and it makes sense to dissect the more … Read more
Mixers are a fundamental component in all RF communications equipment. They are required for nearly all modulation schemes, and have been present in radio in some or another since the beginning. Radio would not be possible without the existence of mixers. Despite their importance in radio equipment, many hams and experimenters are intimidated by them … Read more
When it comes to oscillators, one technology that has greatly risen in popularity these past few years is DDS – Direct Digital Synthesis. An increasing number of ham projects are using DDS chips, and it is possible to find RF-capable chips at relatively affordably prices. With easy-to-use micro-controller development boards such as the Arduino, using … Read more
The Phase-Locked Loop (PLL) is one the most popular building blocks of any RF system. Understanding the PLL unlocks many possibilities for the experimenter, however many hobbyists and those relatively new to electronics are put off by its apparent complexity. While PLLs can seem daunting, by understanding the main principle behind PLL theory and dissecting … Read more
Introduction No component is as connected to ham radio history than the quartz crystal. Still today, thanks to their excellent frequency stability and cost-effectiveness, crystal oscillators in one form or another dominate the electronic landscape. You’ll find them in nearly every electronic device you can think of, from PC motherboards to your wristwatch. And, of … Read more
While it is true that at first glance oscillator circuits can seem complicated, in truth, despite the hundreds of different oscillator designs available, they are all derived from just a few possible architectures. Knowing the fundamental theory and architecture behind oscillator circuits will allow you to make sense of most oscillator designs, and also allow you to design your own.
In the previous post we went over passive LC filter design. LC filters do have many advantages: they are simple to understand and design and they don’t require an external power supply. They also are the only solution for higher frequencies. That said, they cannot provide gain. Instead, some power is lost when the signal goes…
The math behind filter design is actually very complex, and the equations that determine component values are complicated. Fortunately, most of that complexity will be transparent to you! Good news, you’ll never have to work from scratch when designing filters. Instead, filter design relies on using tables of normalized values, then extrapolating these values…