Greetings, I've purchased the SDRT book and I'm currently waiting on delivery.
In the meantime, I'm hunting around trying to source components I know I'll need, starting with the Teensy 4x.
One thing that strikes me straight away is the steep price of the Teensy compared with other Arduino platforms I'm familiar with (Nano, etc) and that's before you include the sound processing extension.
So, the obvious question would be: has anybody tried to replace the Teensy with a comparable (caveat!) platform, like the STM32 (BluePill)?
The caveat being that from what I understand, the Teensy has more grunt.
Since my plan at this stage is to treat the T41 as a great example of how to build an SDT in general and perhaps actually building something slightly simpler (an 80m SSB mono-bander would do me just fine!) I wonder then if you can loosen some of the constraints (starting with the Teensy).
I may be way off the beam, of course.? Regards.

开云体育

First, thanks for buying our book. I hope it's been a useful read.

I've worked with most of the common microprocessors and considered most before I settled on the Teensy 4.1. There are a bunch of reasons why I chose the Teensy. First, it has the resource depth (e.g., memory and I/O pins) necessary to do a "real" SDT. Second, it has the requisite horsepower: a 600MHz clock and floating-point processor. Third, it is supported by a robust library that will do almost all major tasks and I "trust" its libraries. Fourth, the Teensy 4.1 board is well-defined while others are not (e.g., the ESP32 boards have dozens of variations and not all ESP32 libraries work with all boards--indeed, some boards have 32 pins, others have 38). Fifth, it works in the current IDE and PRJC makes a real effort to keep it and the supporting libraries current with the IDE. And sixth, it supports the RA8875 display, which gives us a choice of 5", 7", or 9" display. All of the above combine to give the T41 a feature set that is unlike other SDTs (e.g., we can show a 192KHz bandwidth).

That said, the purpose of the book is to bring much of the DSP theory into one place, discuss it, and show why we elected to use the circuits we do. We've tried to write the book in an "approachable" manner, making the reading a bit easier than most DSP books, but still giving the reader what they need to know. The book, and the T41, are a jump-off point and we encourage experimentation. Indeed, much of the improvements in the T41 over the past two years are from posters to this site. Developments in the STM32, ESP32, and RP families continue to improve their performance stats to the point where they become viable alternatives to the Teensy 4.1,. We hope others pick up the essence of the T41 and continue to run with it.

Jack, W8TEE

Thanks for the advice guys.? You make a convincing argument for the Teensy, so I'll be sticking between the lines on that one.

As an analogue transceiver builder, I'm really looking forward to learning something new.? Also, I'm enjoying reading "Digital Signal Processing A Practical Guide for Engineers and Scientists" by Smith as an accompaniment to your book.? Since I'm in the Lit / Research phase of the project, I might ask if you had any personal recommendations of books that offer intuitive insights into DSP (although it's hard to beat Smith in that regard!)

But perhaps that's the subject of another thread.
P.S. the book has just arrived.? It's going to be a long night!
73

Not a book, but an online course:



There are lots of exercises using Python.? This is one of my favorite technical courses.? I didn't take it for credit, only for learning.
This course covers the fundamental basis of DSP.

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73 Greg KF5N

Thanks for the link. It looks like a useful course.

I'm curious as I started a Coursera course a couple of years ago. I won't say which university it was through, but I'm pretty sure it was in Colorado. It was on sensors and motors as in process control, and it was much more detailed than I expected. I'm not exactly a rookie, but it was going to take a lot of study. I reported some problems with equations being wrong (units didn't work out, etc.) and I got no response from the instructors. Several other students reported that quizes had some wrong answers and also got no resposne. I dropped out due to lack of instructor support.

How was your experience with this course?

It has been a few years since I took it, but it was top notch instruction.? Also very unique, since the data being analyzed is music.? A refreshing change from the usual dry engineering material.
I had better understanding of the DFT and data sampling than from any other source I had studied before.

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73 Greg KF5N

Having worked with most of the Arduino line and several other microcontrollers, including the Blue Pill - the Teensy has a whole lot going for it, especially
for demanding applications like SDR. Some of the Blue pill brothers have the raw power, but the question is do they have the wide library support that Teensy has? There is also the question of a suitable higher res screen. You need at least the 800x480 pix to show what the T41 has. On the grand scale of things, you would not be saving much if you do want performance. - Note that even RASPI is much more expensive that Teensy 4,1.

A primary requirement of the T41 Sw is support for the ARM DSP library. Other micros do support it, but that is a basic need. Doing a port of T41 SW to the STM32 family would be a pretty large task, IMHO.

Just my 2 cents worth.
Al
AC8GY

On 2023-09-20 15:12, Albert Peter wrote:

Having worked with most of the Arduino line and several other
microcontrollers, including the Blue Pill - the Teensy has a whole lot
going for it,

I was wondering if there would be any point to ditching the Teensy and just
using its CPU, the IMXRT1062. Not to save money, but to have less pins, less
board real estate. AND to have genuine JTAG debug. And there are better IDE's
out there...

One problem with that, is that the exact CPU in the Teensy is a BGA ( Ball Grid
Array ). I'm damned good at soldering, but that's where I draw the line.

- Jerry, KF6VB

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Jack, W8TEE

Someone made an interesting FPCB to access JTAG for Teensy 4.1:


It looks like it has to be for a Teensy 4.1 without Ethernet.

I'm sure Paul (pjrc) has read the threads that ask for JTAG access or a "development" Teensy with JTAG access.? Maybe, one day.....

Ian?

I looked at the Debug Mod Project.? ?I believe that the Arduino IDE will no longer be able to work properly, so we'd have to move to Platform I/O, VSCode or eclipse.? Also libraries are added to the project in a different way.? In that way, it becomes more of a tradition embedded project, which I don't mind, but it may be more intimidating for others.

There is something called GDBStub that is supposed to work without hardware modification, but the last time I tried it, I didn't have much luck.

73,
Jack KC7VLO