What is a Constellation Diagram?

Figure 1. QPSK constellation.

A constellation diagram is a diagram that shows how the information in a digital modulation scheme such as phase shift keying (PSK) is represented in a modulated carrier. This article is a bit of an experiment; instead of introducing the constellation diagram by simply presenting it… read more

Submitted on 25 March 2019

This Person Does Not Exist

Persons that don't exist.

The image below shows eight faces that were generated through a machine learning technique called a Generative Adversarial Network (GAN). The faces are completely artificial, and do not correspond to… read more

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Submitted on 5 March 2019

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

One Code to Run Them All (Python 2 and Python 3)

Quite a while ago, I decided to do all my Python programming in Python 3 as much as possible. This is essentially always for the typically small stand-alone programs that I put on this blog. I did this to encourage people to use Python 3 for their own work, and to be future proof. Additionally… read more

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Submitted on 26 January 2019

Old Style Linear Regression with TensorFlow

Figure 1. Line fitted through linear regression.

This article shows how “old style” linear regression looks when implemented with TensorFlow. When you start diving into TensorFlow, an example like this is typically missing from the tutorials. Linear regression is often the first example, but… read more

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Submitted on 3 December 2018

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