cepstrum

I was working in this department for a fellow named Manfred Schroeder. And he explained to me some idea for how to do pitch detection. That's understanding the fundamental frequency of speech used on all cell phones nowadays. He had some idea how to do that. It’s called the Cepstrum and I implemented it that summer.

A. Michael Noll, A. Michael Noll on When It All Started

But now I had, during that summer, access to this incredible IBM 7090 computer, huge computer system. And it had an incredible graphics machine on it, the microfilm plotter, cathode ray tube, used mostly for printing text, but also could do graphics and plots, which I was using to plot the results of the cepstrum analysis.

A. Michael Noll, A. Michael Noll on 1960s Computer Art at Bell Labs