Good article on Frequency warping and using the bilinear transform

Started by dcomer 1 month ago3 replieslatest reply 1 month ago132 views

Most of you probably are well familiar with's website and the really cool educational products they offer. This morning, my email subscription to their news letter had a link to an article on "Frequency warping using the bilinear transform." the link on Digilent's newsletter leads to 

I would post the original Digilent Newsletter link, but you are required you to subscribe, so... I will say, that with respect to Digilent's products, I find their support excellent in terms of blog posts, and how-to-use, etc.

There are clearly MANY excellent experts on this forum that may find this "been there done that." I thought I would share the information hoping those, like myself, that are constantly seeing more information and learning (probably all on this forum, right?) find the article useful.

I hope you find this interesting as I did,


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Reply by Rick LyonsMay 18, 2022
Hi Dave. Thanks for posting information regarding Digilent Inc. I wasn’t familiar with that company. They definitely offer a super-wide variety of hardware for a young engineer, or hobbyist, to learn about signals, signal processing, and FPGAs. Their ‘Analog Discovery 2’ device certainly looks interesting!
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Reply by dcomerMay 18, 2022

RIck, you are more than welcome. I started looking at Digilent right after they first started a business; It had to be in the 1980's right after the Internet was becoming widely available and probably around the time that Jeff Bezos started Amazon (oh am I getting old?) The key drawback then is they collaborated with Xilinx and it was one of the few places you could get ahold of the early Xilinx development boards. In fact, at one point I think they only sold to educational institutions, but that may not be accurate.

When I started my home lab I was able to purchase a Tektronics 4-channel scope but that was about it. Spectrum analyzers, VNA, and network analyzers were way out of reach of my personal budget. Today with the digital signal processing wave, there are so many options. I was finally able to afford some of the Rigol offerings (GHz BW scope, Spectrum analyzer), but I still find some products on Digilent worthwhile to tinker with. If they were to come out with a "lower" cost RFSOC kit that would be interesting. When you and I met back at Signetics when you taught your DSP course (Dang that was great!!!), it was not long after that a company called LTX came out with a test platform that had a 20MHz wideband sampler front end on their mixed-signal IC test system. That's where I cut my teeth on disk drive read channel testing. If you recall, I posted an Amazon review of your first edition "Understanding Digital Signal Processing" that, if I recall correctly, was titled "saved my career." It was true. Coupled with a book that an engineer at LTX (I think his name was Mahoney) wrote, your book help me understand the front end of that tester, single tone filter testing, etc.

So, there is plenty of material out there for young engineering students, hobbyists, and amateur radio operators to learn nowadays, not to mention "Goggle", but nothing like targeted kits, old-fashioned paper books, or eBooks to round your out.

Geez, I forgot to mention; Dan Bochen's class "DSP for Wireless Communication" begins today. Time to download my material and get to work!



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Reply by Rick LyonsMay 19, 2022

Hi Dave. I wish you all the best with your "DSP for Wireless Communication" class. Dan Boschen has much to teach us.