What modest academic success I’ve had in the area of cyclostationary signal theory and cyclostationary signal processing is largely due to the patient mentorship of my doctoral adviser, William (Bill) Gardner, and the fact that I was able to build on an excellent foundation put in place by Gardner, his advisor Lewis Franks, and key Gardner students such as William (Bill) Brown.

For a long while, since 2015, the CSP Blog was the only website on the planet devoted entirely to cyclostationary signals and cyclostationary signal processing. No more! Gardner created a website in 2018 called cyclostationarity.com. Go check it out if you want a different perspective and emphasis relative to the CSP Blog.

I don’t think the two CSP websites will have a lot of duplicated material. The CSP Blog is intended for *practioners* of signal processing; it looks to me like cyclostationarity.com is aimed at providing accessible versions of *theoretical* concepts and results. That mirrors how I think of myself and Gardner–I am not his equal at theory, but I don’t think he directly programs computers or processes data.

It seems appropriate at this point to provide some historical foundational documents of CSP. These are documents that can be found on the internet, with a little effort, but I thought it would be nice to put them all on one page. The first is the book Signal Theory by Franks. It is a book on random processes, signal representation and analysis, and topics like signal detection. There is some cyclostationarity in there too.

The second is the doctoral dissertation of Gardner. This is of interest to serious scholarly researchers in the field, such as doctoral students who are plumbing the depths of the history of signal theory and cyclostationary signal processing.

The third is the doctoral dissertation of Brown. Key topics include detailed presentation of the fraction-of-time probability approach to signal analysis, periodically time-variant linear filtering for complex-valued signals, introduction of computationally efficient spectral correlation function estimators, and analysis of the variance (SNR) of the outputs of such estimators.

My doctoral disseration is also available here. It focuses on higher-order cyclostationarity.

Comments are welcome.

## Author: Chad Spooner

I'm a signal processing researcher specializing in cyclostationary signal processing (CSP) for communication signals. I hope to use this blog to help others with their cyclo-projects and to learn more about how CSP is being used and extended worldwide.
View all posts by Chad Spooner

Hi Chad, what a small world! I don’t remember the occasion, but I met Dr. Bill Gardner in California on business and he gave me one of his books. I was in Technical Surveillance Countermeasures at the US Secret Service and remember wanting to put his work into practical application in my work for obvious reasons. What I didn’t know was that Bill Brown was a student of Gardiner’s. I’ve know and been friends with Bill Brown for many years. Thanks for creating this blog and I’ll be following it, especially interested in the concept of AI automating the detection and classification process of cyclostationary signals.

Hey Steve! Thanks for checking out the CSP Blog and the comment. I really appreciate it. I hope you find some useful information on the Blog. Drop me a line some time (cmspooner at ieee dot org) if you have ideas for posts that you’d like to see.