Mic pre-amp and equalizer with DSP audio compressor (Part 3)

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Presenting a ham radio (and CB) microphone pre-amp and equalizer with DSP audio compression capabilities using a Teensy microcontroller and Teensy Audio Shield.
Part 1 - Project introduction: • Mic pre-amp and equali...
Part 2 - Technical details and build: • Mic pre-amp and equali...
Part 3 - Added functionality: Noise Gate, Auto Make Up gain, better compressor and Limiter (this video.)
Part 4 - Analyzing the response of the device: • Analyzing the response...
00:00 - Summary
00:27 - Channel intro
00:50 - Explaining the setup used on the video
03:00 - New features and improvements
04:15 - Listing of features and improvements over the original version
09:04 - Testing the Noise Gate functionality
10:00 - Testing the Compression functionality
10:35 - Testing the Equalizer functionality for DX mode
11:35 - Testing with Yaesu clone microphone
12:55 - Software changes and improvements
23:28 - Closing
Code: github.com/VA3HDL/DSP_Pre_Pro...
Parts List
========
- Teensy 4.0 USB Microcontroller Development Board
- Audio Adaptor Board for Teensy 4.x (SGTL5000 Audio Codec IC)
- OLED 128x64 screen or better
- Encoder with push button
- Headers male/female for connections
- Perfboard
- 600:600 ohms isolation transformer (1:1)
- 7x 0.1uF ceramic capacitors for RF filtering
- 1uF electrolytic capacitor
- LM317 or LM7805 to regulate input voltage to 5v DC
- 2x RJ45 jacks
- Wire for jumpers
- Shielded wire for audio jumpers
- Project box or PVC sheet to build your own box
Teensy Audio Library GUI tool: www.pjrc.com/teensy/gui/index...
► If you have any questions or comments please leave them below
► For more articles and information about my other projects please check my website www.va3hdl.com

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Опубликовано:

9 июл 2024

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Комментарии : 15

@magomme3399 Год назад

Hello Pablo, very nice HAM-Radio project. Where can i found the libaries ? martin

@VA3HDL Год назад

Hi Martin, all my code is available in GitHub here github.com/VA3HDL - For this specific project the latest version is in this repository github.com/VA3HDL/DSP_Pre_ProcessorV5 - Thanks for watching!

@magomme3399 Год назад

@@VA3HDL Pablo, was searching for the ClickEncoder.h but found it today. Also found the menuIO libary. Actually it runs. Thx again. Looks like a really good gadget my friend. 73 de OE9SAU

@VA3HDL Год назад

@@magomme3399 I'm still using it every time when I work with the FT-757GX in HF. I'm very happy also with the results. The box looks really ugly and didn't come out the way I intended. Maybe one day I will move everything to a proper enclosure. Let me know when you finish your project and we can try a QSO if you want. 73

@user-se8hq6qf5e 9 месяцев назад

Wow, really amazing project! Wow your compressor is really working overtime! Since the biquad filter can have up to 4 filters, is there any advantage to having 8 separate biquads?

@VA3HDL 9 месяцев назад

It was a great project indeed and I still use it. I've added a tone generator to help trigger the external autotuner. I took the open source code and rewrote most of it. However, I kept the same 8 filters. I didn't investigate why they did it that way originally and it worked fine for me. This is an area that can be improved in the code. Maybe this winter I'll take another look. Thanks for pointing this out!

@theweazel 9 месяцев назад

@@VA3HDL Where did you get the Clickencoder.h and menu.h?

@VA3HDL 9 месяцев назад

@@theweazel github.com/BennehBoy/clickEncoder and github.com/neu-rah/ArduinoMenu - Are the two libraries I've used.

@theweazel 8 месяцев назад

@@VA3HDL Thank you

@yv6eda 2 года назад

Great work Pablo! Felicitaciones! A little too much for me but amazing build!

@VA3HDL 2 года назад

Gracias. Thanks for watching! 73

@JRNelson78 Год назад

Can this be used for a full frequency response audio on LINE IN input? Also, equalizer settings can be changed? I mean center frequencies of the bands, let`s say 50Hz, 250Hz, 1KHz, 14000Hz etc.. As i see 7 bands in the documentation, but 8 bands are in use?

@VA3HDL Год назад

Yes, it can be used. Yes, equalizer settings (gain/att. only) can be changed on the fly. However, the center frequencies on the bands are hardcoded, they could be also parametrized, but it wasn't needed for my particular application. The code is available on my GitHub. I'm not sure what documentation are you referring to. If it is the book, then it will not match 1:1 because I heavily modified the code to use "true" DSP capabilities in the code, rather than what was built in on the audio codec.

@JRNelson78 Год назад

@@VA3HDL I see it in the PDF documentation of the SGTL5000 chip. There it says 7 band parametric EQ, but how it can be 8 i don`t know. Do you know of such chip or project with some digital board, that can be done to a compressor limiter, may be filter. I know there are such things from ST, Texas Instruments and others, but which one is powerful enough for this.....

@VA3HDL Год назад

@@JRNelson78 Now I understand your question. The PDF is only describing what is built-in on the audio codec chip itself. I'm using very little of that functionality as I found programming the DSP functions on the Teensy to be more flexible and adaptable to my needs. You can turn on and off the built-in features on the audio codec chip. I turn them off and went with my own equalizer settings, own compression, limiting, make-up, filtering, etc. functions. I even added a tone generator to tune my radios. It is a very powerful combination with the Teensy. There are few other videos in RU-vid covering only the features of the Teensy "audio shield". Check this page also www.pjrc.com/teensy/td_libs_Audio.html