See Ya', Rick

Rick Lyons passed away last Wednesday.

Unfortunately, I never had the chance to meet him in person. In close to twenty years of working together, we never once spoke on the phone. Everything I know about Rick, I learned from a few hundred emails and from watching what he did for the people who read this site.

He published his first post here on November 3, 2007, "A Differentiator With a Difference." His last one went up on September 25, 2023, "Algebra's Laws of Powers and Roots: Handle With Care." Between those two dates he published 88 posts on DSPRelated. They have been read just over 1.28 million times and have collected more than 1,300 comments, which is close to a quarter of every blog comment ever left on this site.

In addition to writing blog posts, Rick had been answering questions in DSP forums for decades. Between the old comp.dsp archive and the DSPRelated forum, he left roughly 2,800 posts. The overwhelming majority of them are answers to somebody else's question.

"Darn it!"

Rick's emails to me followed a format he invented early on and never once deviated from. The subject line was always some variation of "Lyons' 75th blog (Reducing IIR Filter Workload)." He kept his own count. He referred to himself in the third person: "A request from Lyons." "A question from Lyons." "Lyons needs your help."

He signed off "See Ya'," and then "[-Rick-]", in square brackets, every single time.

And then there were the corrections. So many corrections. "One of our readers detected a typo." That sentence appears in my inbox over and over, for posts published five, ten, thirteen years earlier. A missing minus sign in Equation 8 of the CIC filter post. Version 3 of a PDF because he had found something wrong in Version 2. One of his emails is titled "Another darned PDF file update for Lyons' 86th blog," and it opens with a single line: "Darn it!"

He was, by a wide margin, the most meticulous person I have ever worked with. He once mentioned in passing that a post had taken him 60 to 80 hours, most of it spent on the PDF. He would not let me publish a post before its PDF was attached, because he didn't want a reader to show up and find the download missing.

"Send me an e-mail and I'll send you the errata"

Understanding Digital Signal Processing was Amazon's top-selling DSP book for seven straight years. If you work in this field, you have either read it or been told to.

Its title comes up in more than 350 separate messages in our forum archives alone, nearly always someone pointing a beginner toward it. In 2005, Rune Allnor started a thread here titled "Rick's book has reduced my workload by 90%."

Countless times in our forum archives, he answered a stranger by offering to send them something personally: a chapter of his own book, an errata sheet, a derivation he had worked out and never published. "If you buy a copy of my book, please send me an e-mail and I'll send you the errata." "If you send me a private e-mail, I'll e-mail you a copy of my description of that process."

When I once went three days without replying to an email, he wrote: "Is everything OK with you? So I became worried about you."

That was Rick.

100

On September 25, 2023, I published his post on Algebra's Laws of Powers and Roots and sent him an email to thank him for another great post.

He replied a few hours later:

"Thanks. I was hoping to produce 100 blogs before I die. I don't think I'm going to make it.
Thanks again,
[-Rick-]"

It was the last post he ever wrote.

He stopped at 88. Nobody who learned from them was counting.

One more yes

For years I invited Rick to speak at the DSP Online Conference, and for years he turned me down, always for the same reason; he couldn't think of a DSP topic he could present that he had not previously presented in one of his blogs. 

Then in the summer of 2024, he proposed a session on Interpolated FIR (IFIR) Digital Filters, and he delivered it.

He sent me a photo for the conference website and it is the photo at the top of this page.

In June of last year, I asked whether he would join us at the first Signal Processing Summit in Silicon Valley. "Thank you for your very kind invitation. But I'm sorry to say that my personal life doesn't permit me to attend a San Jose conference."

On June 30 of this year, I sent Rick a short email. "It's been a long time. I thought I would reach out to ask how you are doing, in the hope that you are healthy and happy."

He never answered it. I understand why now.

To Rick's family, I offer my deepest sympathies. I hope there is some comfort in knowing that the man you knew at home was, to a few hundred thousand strangers scattered all over the world, the person who finally made it make sense.

If Rick's writing helped you at some point in your career, and I suspect it helped a great many of you, please leave a comment below. I'd love for this page to become somewhere our community can thank him properly.

See Ya', Rick.

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