## Digital PLL's -- Part 1

1. Introduction

Figure 1.1 is a block diagram of a digital PLL (DPLL).  The purpose of the DPLL is to lock the phase of a numerically controlled oscillator (NCO) to a reference signal.  The loop includes a phase detector to compute phase error and a loop filter to set loop dynamic performance.  The output of the loop filter controls the frequency and phase of the NCO, driving the phase error to zero.

One application of the DPLL is to recover the timing in a digital...

## Stability or insanity

May 17, 20161 comment

I've just spent over two weeks getting ready to do my next video.  It was a combination of one of those vast underestimations one occasionally makes, combined with falling into a bit of an obsession.

I am, at this point, not only wondering if it was worth it, but questioning my sanity in carrying on even when the going went beyond tough to just plain crazy.

At any rate, a good video needs a visual aid, and I decided that my video needed to demonstrate stability with a pendulum....

## PID Without a PhD

I both consult and teach in the area of digital control. Through both of these efforts, I have found that while there certainly are control problems that require all the expertise I can bring to bear, there are a great number of control problems that can be solved with the most basic knowledge of simple controllers, without resort to any formal control theory at all.

This article will tell you how to implement a simple controller in software and how to tune it without getting into heavy...

## 3 Good News

March 9, 20161 comment
Good News #1

Last week, I announced a new and ambitious reward program that will be funded by the new Vendors Directory.

This week, I am happy to announce that we have our firsts two sponsors!  Quantum Leaps & Abelon Systems have agreed to pay the sponsorship fee to be listed in the new Vendors Directory.  Because of their support, there is now some money in the reward pool ($1,000) and enough to pay for the firsts 500 'beers' awarded. Please... ## Go Big or Go Home - Generating$500,000 for Contributors

In a Nutshell
• A new Vendors Directory has been created
• Vendors will be invited to pay a sponsorship fee to be listed in the directory
• 100% of the basic sponsorship fee will be distributed to the *Related Sites community through a novel reward system
• The goal is for the directory to eventually generate - drum roll please -  $500,000 on a yearly basis for contributing members on the *Related Sites • Members will choose how the reward money gets distributed between... ## The New Forum is LIVE! February 18, 20161 comment After months of hard word, I am very excited to introduce to you the new forum interface. Here are the key features: 1- Easily add images to a post by drag & dropping the images in the editor 2- Easily attach files to a post by drag & dropping the files in the editor 3- Add latex equations to a post and they will be rendered with Mathjax (tutorial) 4- Add a code snippet and surround the code with ## Ancient History January 18, 201612 comments The other day I was downloading an IDE for a new (to me) OS. When I went to compile some sample code, it failed. I went onto a forum, where I was told "if you read the release notes you'd know that the peripheral libraries are in a legacy download". Well damn! Looking back at my previous versions I realized I must have done that and forgotten about it. Everything changes, and keeping up with it takes time and effort. When I first started with microprocessors we... ## What IS an electron? December 21, 20155 comments When I was a student I got kicked out of a professor's office for having the gall to say that an electron was nothing more than a theory. I still believe that. It is an amazing and awesome theory, and the more we learn the more wonderous the theory becomes. The word electron first appeard in 1891 long after electricity had been in use. In 1897 the electron was discovered by J.J. Thompson who proved it was a sub atomic particle. By this time we already had electric lights. In fact... ## The Art of Debugging December 11, 20151 comment Debugging electronics is similar to any technological process. In theory we know how things are supposed to work, in reality they don't behave as expected. The challenge of engineering boils down to making things work, and debugging is the fundamental task we use to go from lumps of sand to picosecond accurate switching networks. Debugging is an art that requires a lot of time to learn. Like any skill, the more we work at it, the better we become. The first... ## Working of the first solid state amplifier November 30, 2015 Introduction Fig. 1. One of the most popular operational amplifier Whenever a circuit designer thinks about amplifier, the first think that pops up in his mind is that of operational amplifier (Op-Amp). The answer is simple op-amps are beautiful (literally), you just have to set the gain of the op-amps with pair of resistors and you are good to... ## Basic hand tools for electronics assembly November 20, 20153 comments Though the software tools vary with different microcontrollers, many hardware tools are the same. If you are working on larger robotic or automotive systems, you will need a 3/8" and 1/2" drive socket set. There are occasions when even larger drive socket sets are needed. For small robots and taking things apart, the 1/4" drive socket set is useful. The sizes usually range from 5/32" to 9/16" and 4mm to 15mm. You will need both shallow and deep sockets, both standard and... ## Go Big or Go Home - Generating$500,000 for Contributors

In a Nutshell
• A new Vendors Directory has been created
• Vendors will be invited to pay a sponsorship fee to be listed in the directory
• 100% of the basic sponsorship fee will be distributed to the *Related Sites community through a novel reward system
• The goal is for the directory to eventually generate - drum roll please -  \$500,000 on a yearly basis for contributing members on the *Related Sites
• Members will choose how the reward money gets distributed between...

## March is Oscilloscope Month — and at Tim Scale!

March 6, 2014

I got my oscilloscope today.

Maybe that was a bit of an understatement; I'll have to resort to gratuitous typography:

I GOT MY OSCILLOSCOPE TODAY!!!!

Those of you who are reading this blog may remember I made a post about two years ago about searching for the right oscilloscope for me. Since then, I changed jobs and have been getting situated in the world of applications engineering, working on motor control projects. I've been gradually working to fill in gaps in the infrastructure...

## Lost Secrets of the H-Bridge, Part II: Ripple Current in the DC Link Capacitor

July 28, 2013

In my last post, I talked about ripple current in inductive loads.

One of the assumptions we made was that the DC link was, in fact, a DC voltage source. In reality that's an approximation; no DC voltage source is perfect, and current flow will alter the DC link voltage. To analyze this, we need to go back and look at how much current actually is being drawn from the DC link. Below is an example. This is the same kind of graph as last time, except we added two...

## Went 280km/h (174mph) in a Porsche Panamera in Germany!

Those of you who've been following my blog lately already know that I am going through some sort of mid-life crisis that involves going out there to meet people and make videos.  It all started with Embedded World early this year, then continued at ESC Boston a couple of months ago and the latest chapter just concluded as I returned from Germany after spending a week at SEGGER's headquarters to produce a video to highlight their 25th anniversary.

## The Other Kind of Bypass Capacitor

There’s a type of bypass capacitor I’d like to talk about today.

It’s not the usual power supply bypass capacitor, aka decoupling capacitor, which is used to provide local charge storage to an integrated circuit, so that the high-frequency supply currents to the IC can bypass (hence the name) all the series resistance and inductance from the power supply. This reduces the noise on a DC voltage supply. I’ve...

## Launch of Youtube Channel: My First Videos - Embedded World 2017

I went to Embedded World 2017 in Nuremberg with an ambitious plan; I would make video highlights of several exhibits (booths) to be presented to the *Related sites audience.  I would try to make the vendors focus their pitch on the essential in order to produce a one to three minutes video per booth.

So far my experience with making videos was limited to family videos, so I knew I had lots of reading to do and lots of Youtube videos and tutorials to watch.  Trade shows are...

## Short Takes (EE Shanty): What shall we do with a zero-ohm resistor?

In circuit board design you often need flexibility. It can cost hundreds or thousands of dollars to respin a circuit board, so I need flexibility for two main reasons:

• sometimes it's important to be able to use one circuit board design to serve more than one purpose
• risk reduction: I want to give myself the option to add in or leave out certain things when I'm not 100% sure I'll need them.

And so we have jumpers and DIP switches and zero-ohm resistors:

Jumpers and...

## Voltage Drops Are Falling on My Head: Operating Points, Linearization, Temperature Coefficients, and Thermal Runaway

January 19, 2015

Today’s topic was originally going to be called “Small Changes Caused by Various Things”, because I couldn’t think of a better title. Then I changed the title. This one’s not much better, though. Sorry.

What I had in mind was the Shockley diode equation and some other vaguely related subjects.

My Teachers Lied to Me

My introductory circuits class in college included a section about diodes and transistors.

The ideal diode equation is...