OSC II.1 – The Phase-Locked Loop

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

OSC I.2 – Quartz Oscillators

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

OSC I.1 – LC Oscillators

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.

FIL I.4 – Active Filters

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…

FIL I.3 – Filter Design Basics

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…

FIL I.1 – Introducing Filters

Filters are an important building block you will find in nearly all fields of electronics.  They are of particular interest to the ham radio experimenter and RF designer.  Out of all the building blocks of radio electronics, filters are perhaps the most simple to understand.  Simple doesn’t mean unimportant however, as filters are a necessary…

AMP II.6 – Amplifier Stability

So far, everything we’ve learned about negative feedback seems to indicate that it is a great tool with little drawbacks.  The only inconvenience we’ve actually talked about was a reduction in gain.  Choosing a device, or a cascade of devices, that provide a big enough gain to start with solves this problem.Unfortunately, negative feedback has…