Gotta say I loved this video!, The sound test at 34:22 was hilarius! HAhahaha, thanks for it!, makes me wanna keep learning the basics of FPGAs, keep up the good work!
Nice idea, what's only really missing, is post-filter feedback going back to the original signal. That will really reduce the distortion. There is actually a company called Axign, who started with exactly this idea and later made it to an ASIC. What's really missing is an easy (open source) implementation
I was not aware of that company called Axign. But yes you are right - instead of taking the feedback behind the quantizer it should be also possible to take the feedback from an external ADC for higher audio quality.
@@YetAnotherElectronicsChannel You probably need a fast ADC for that. Where can I find your contact details? I would like to share a few ideas (or check your diyaudio ;) )
I did a little looking to find out more about that chip. It seems to be in use in a fair few high end amplifiers. For even better performance you would want to use the chip to drive some GaN FETs, which one of two people look like they are doing.
Great video ..There are ways to implement the ADC digitally by using the differential pins on FPGAs .. by the way the comparator could also be implemented that way .And you could use a fixed good external reference analog triangle wave
THANK YOU for all your videos. I just found your channel today and have immediately subscribed. Do you have any plans to demonstrate noise cancelling with Arm M4 series chips? I would love to see how to implement a filter that could be used to isolate human speech from noisy industrial or vehicle environments.
Hello, I noticed that the TinyFPGA-BX board supports open-source software development. May I ask which platform you use for FPGA programming and flashing when using this board?
Maxim Dorogov no I didn’t to be honest. Maybe I can do this as a follow up video some time. The problem is that I was doing the THD measurements for my last Class-D video inside the company I’m working for. But at the moment - due to Corona I’m working from home office only and I don’t have a chance to get in touch with the analyzer.
@@YetAnotherElectronicsChannel I've used a free sofware called ARTA at university for audio measurments, the quality depends of the audio interface of your PC but its not so bad if you want to know the order of magnitud of the thd.
@@neoclassical18 @YetAnotherElectronicsChannel You can also get very high quality audio interfaces that connect over USB for about $100 now. Most are good for up to 24b/192kHz sampling frequencies. I used a Behringer UMC404HD with arta and measured it simply looping the output back into the input. For a 1kHz tone the worst spur was 109dB below the tone. Pretty impressive for the cost! I was going to post the plot but I guess it wont let me. If you don't need 4 channels, the UMC202HD or Focusrite Scarlett Solo are both great.
Hello, very nice project! There is a missing PLL file on the github though. I would love it if you could send it to me, I am trying to implement the project now. Cheers!!
![[#21] Self-oscillating Class-D amplifiers](http://i.ytimg.com/vi/E2LPpjhGIYk/mqdefault.jpg)
![[#21] Self-oscillating Class-D amplifiers](/img/tr.png)
![[#12] Discrete Class-D Amplifier (PWM based)](http://i.ytimg.com/vi/24sBtnnjK34/mqdefault.jpg)
Check out how I implemented a discrete analog Class-D amplifier
th-cam.com/video/24sBtnnjK34/w-d-xo.html
Gotta say I loved this video!, The sound test at 34:22 was hilarius! HAhahaha, thanks for it!, makes me wanna keep learning the basics of FPGAs, keep up the good work!
Wow, lot of info. You worked a lot on this. Thanks for sharing
Thank you sir for such an advanced project.
This was a masterpiece project.
Nice idea, what's only really missing, is post-filter feedback going back to the original signal.
That will really reduce the distortion.
There is actually a company called Axign, who started with exactly this idea and later made it to an ASIC.
What's really missing is an easy (open source) implementation
I was not aware of that company called Axign. But yes you are right - instead of taking the feedback behind the quantizer it should be also possible to take the feedback from an external ADC for higher audio quality.
@@YetAnotherElectronicsChannel You probably need a fast ADC for that. Where can I find your contact details? I would like to share a few ideas (or check your diyaudio ;) )
@@YetAnotherElectronicsChannel ping ;)
I will send you a message a bit later today
I did a little looking to find out more about that chip. It seems to be in use in a fair few high end amplifiers. For even better performance you would want to use the chip to drive some GaN FETs, which one of two people look like they are doing.
Great video, loved it
Thanks for your videos!!!!
Wooow! appreciate it man! keep it up :)
Very nice video, thx a lot!
Great video ..There are ways to implement the ADC digitally by using the differential pins on FPGAs .. by the way the comparator could also be implemented that way .And you could use a fixed good external reference analog triangle wave
Great video, got me interested to create something similar
Servus! Very interesting videos, thank you for sharing!
THANK YOU for all your videos. I just found your channel today and have immediately subscribed. Do you have any plans to demonstrate noise cancelling with Arm M4 series chips? I would love to see how to implement a filter that could be used to isolate human speech from noisy industrial or vehicle environments.
30:40 shows hardware setup
Hell yea
can you please tell the product name of i2s module you are using.
Hello,
I noticed that the TinyFPGA-BX board supports open-source software development. May I ask which platform you use for FPGA programming and flashing when using this board?
Amazing project! I never heard about noise-shapers at my university, Have you measured the THD (Total Harmonic Dist.) of the system?
Maxim Dorogov no I didn’t to be honest. Maybe I can do this as a follow up video some time. The problem is that I was doing the THD measurements for my last Class-D video inside the company I’m working for. But at the moment - due to Corona I’m working from home office only and I don’t have a chance to get in touch with the analyzer.
@@YetAnotherElectronicsChannel I've used a free sofware called ARTA at university for audio measurments, the quality depends of the audio interface of your PC but its not so bad if you want to know the order of magnitud of the thd.
@@neoclassical18 @YetAnotherElectronicsChannel You can also get very high quality audio interfaces that connect over USB for about $100 now. Most are good for up to 24b/192kHz sampling frequencies. I used a Behringer UMC404HD with arta and measured it simply looping the output back into the input. For a 1kHz tone the worst spur was 109dB below the tone. Pretty impressive for the cost! I was going to post the plot but I guess it wont let me. If you don't need 4 channels, the UMC202HD or Focusrite Scarlett Solo are both great.
The noise floor is too high. Maybe because you are using the ADC. Would you try to use a pure digital signal (not conversion at all, using the USB)?
Hello, very nice project!
There is a missing PLL file on the github though. I would love it if you could send it to me, I am trying to implement the project now.
Cheers!!
maybe it is possible using a uC with DPLL like samd21. You can achieve very low jitter with it.
hi, so if you increase the noise shaping to 6th order? the SNR will improve drastically :)
can you please tell the product name of i2s module you are using.