Blog posts

2018

Plotting the FFT of a voltage signal

3 minute read

Published:

Plotting a signal in the frequency domain is a fundamental analysis tool which can provide great insight into the signal’s behaviour. Something I have struggled with in the past is getting the units correct such that the amplitude response of the frequency-domain representation has physical significance. In this blog post I aim to outline how to properly find useful units with which to represent voltage signals.

Measurement Gotchas: systematic error when averaging

2 minute read

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When trying to capture a clean signal from an electronic circuit, a popular strategy is to use averaging. The circuit is driven by the same signal repeatedly creating a set of output signals which can then be averaged, thus reducing noise. I’ve used this technique a lot in the measurement step of my work on training physical models on measured data (see my DAFx-16 paper for more information).

Component meters: DE-5000 and M328

2 minute read

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Recently I’ve been in need of measuring linear component values to a high degree of accuracy, so decided to purchase a couple of component meters. The first of these is the M328 “transistor tester”, which is a favourite of the DIY community as it is cheap and has all of the plans available on the internet. I put transistor tester in quotes as the meter is designed to measure resistance, capacitance, inductance, transistor type and basic characteristics, and even some parasitic properties. This is quite an impressive boast for a product which I purchased for £6.32!

2017

Modelling logarithmic potentiometer laws

3 minute read

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This post presents a general logarithmic potentiometer law with a curve fit to enable a user to choose a curve that sounds good in their application. The law is computationally expensive as it involves an exponent but is good in terms of flexibility.

Mathjax Test

less than 1 minute read

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This is a test page to see if Mathjax is working. \(\pi\)