Spectral Analysis – a Fourier transform tutorial – part #1

March 28, 2011

This is a basic tutorial about implementation of a standard Fourier transform model in Excel. It is not an introduction to Fourier analyis. You could choose to familiarize yourself with the subject before proceeding with this tutorial. Solving a few Fourier transform excersises would be of help too. Essentially, this part shows you how to adapt the general Fourier formula for a continuous real signal to a sampled signal having a limited number of samples.


Brownian Motion Animation – a 2D random walk diffusion tutorial

March 27, 2011

This is a tutorial about the creation of an animated diffusion model based on the random walk principle. There are two different models, one based on a lattice style diffusion (the particles can move in a series of steps of a fixed distance, but only in multiples of a 90 degree angles: 0, 90, 180, 270) and one based on a fluid style diffusion in which the particles can move…


A 2D Random Walk Animation Tutorial

March 26, 2011

This tutorial explains how to build two animated random walk models, one where the particle is confined to square grid and one where the particle is free to step in any direction. The first model is adequate for modeling particle movement in solids while the second is more fit for modeling particle diffusion motion in fluids.


A 2D Random Walk Model – the “drunk man” animation

March 25, 2011

This is a model simulating a two-dimensional random walk in two variants, one by using a digital angle (in 90 degrees increments) and one using an analog angle between zero and 2*pi.  This type of model (similar to the walk of a very drunk man) pertains very well to numerically solving Monte Carlo diffusion type problems.  It is a brute force model using a lot of computer time and resources typically employed when the…


The Melting Snow Castle – a diffusion model application

March 24, 2011

This is an application to the previously derived 2D diffusion (heat transfer) model. The snow melting process is very similar to diffusion or heat transfer. Just open the model and hit “Start-Pause” to see for yourself. It is a 2003 model or earlier. I wasn’t able to run it in 2007 with animation but I’ve got some friends who managed to run it with no problem (except speed). The graphics is very…


Building a Dynamic Two Dimensional Heat Transfer Model – part #1

March 22, 2011

Here is the first part of a tutorial which shows how to build a two dimensional heat transfer model in Excel. The presentation shows how to partition a square plate in elementary elements on which the simplest form of the heat storage and heat transfer equations can be applied. The numerical form of the final temperature formula is derived .


A Basic 2D Animated Heat Transfer Model (a diffusion model too)

March 21, 2011

Here is a basic 2D heat transfer model. The first  five worksheets model square plates of 30 x 30 elements. The last worksheet is the model of a 50 x 50 plate. You can modify the initial temperature by hand within the range C21:AF240. It is also a diffusion model. It uses the storage and transport equations derived in the previous tutorials. The temperature calculations are done all  with a single repetitive…


Animated Heat Transfer Modeling for the Average Joe – part #2

March 18, 2011

This is a continuation of the first part of the beginner series of tutorials in heat transfer modeling. The first part introduced the reader to the concept of heat capacity (being analogous to the electrical capacity).  This section continues with the concept of heat conductance which is analogous to the electrical conductance.  Ohm’s law applies.  Toward the end, the principle of using both concepts together (heat storage and heat conduction)…


A One-Dimensional Dynamic Heat Transfer Model – a diffusion model

March 16, 2011

Hi guys, Here is a 1D dynamic model I built today simulating heat transfer in a 21-segment bar. Just click on the orange “Demo” button for a quick demo. Hitting “Reset” sets the 21 segments of the bar to the initial conditions which is a fully customizable initial temperature map. Clicking “Start/Pause” starts the simulation and you can watch the bar temperature profile slowly settling to equilibrium. I recommend you leave the simulation…


How to Model a Phase-Locked Loop (PLL) in Excel – part#3

March 13, 2011

This is a continuation of the PLL series of tutorials and it takes the recursive numerical formulas derived in the previous section, implementing a dynamic spreadsheet  model with help from a copy-paste loop type of macro. This macro emulates the behavior of the phase locked loop model in time. At this point, the model is functional. Charting options for the waveforms will be discussed in the following section.


How to Model a Frequency Modulated (FM) Signal – an insight

March 12, 2011

Both frequency and phase modulation are important not only in electronics but also in science and physics in general. It seems like a trivial chore but when I first tried to model such a signal some time back I hit a hard wall. Our minds easily understand kinematics concepts such as coordinate, speed, acceleration and the relations between them in real life situations, but phase, frequency and angular acceleration are…


How to Model a Phase-Locked Loop (PLL) in Excel – part#2

March 11, 2011

This is a continuation of the PLL series of tutorials and it starts by implementing and testing the low pass filter created in the previous section. After that, the block diagram is updated and the presentation begins to show how to build the PLL model in a worksheet using the existing LPF formulas.


How to Model a Phase-Locked Loop (PLL) in Excel – part#1

March 9, 2011

A Phase-Locked Loop is a type of electronic circuit. It generates an oscillation with the same frequency as a reference oscillation and a relatively constant phase difference  with respect to the same reference. The applications spectrum of such a circuit are extremely wide. Signal modulation, demodulation, detection and filtering, frequency conversion and synthesis are just a fraction of what this circuit can do. Though very simple, it is often not enough understood in industry by…