Signal Processing

What is an Analytic Signal?

Figure 1. Spectra of cosine (left) and complex exponential (right).

An analytic signal is a signal without negative frequency components. This might seem a strange concept if you’re not used to it, but analytic signals are used in signal processing, for example in modems for telecommunications. Let’s start from… read more

Submitted on 25 February 2019

Modems

I’m working on a series of articles on modems. It’ll be a loose collection of posts, and not a true multi-part article such as the one on tomography. Modem technology is not widely known and/or understood, even by a technical audience. However… read more

Submitted on 13 February 2019

How to Create a Configurable Filter Using a Kaiser Window

Figure 3. Frequency response of a low-pass filter with a Kaiser window; A=60.

This article explains how to create a windowed-sinc filter with a Kaiser (or Kaiser-Bessel) window. The windowed-sinc filters in previous articles typically had two parameters, the cutoff frequency and the transition bandwidth (or rolloff). With a Kaiser window, there is a third input parameter, the ripple. For the specific case of the Kaiser window, the same… read more

Submitted on 26 December 2016

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