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  • DD4WH's Avatar
    08-21-2019, 08:50 PM
    hi Brian, re: 1.) have a look at https://github.com/g0orx/wdsp/blob/master/firmin.c line 243: "k = (k + a->idxmask) & a->idxmask;" I am not sure how I should interpret that (and maybe this causes the faults...
    19 replies | 613 view(s)
  • DD4WH's Avatar
    08-21-2019, 08:21 PM
    Blackaddr, thanks a lot for your detailed explanation! OK, I now understood the difference between the I2C and the I2S problems ;-). But I am still struggling with my problems, could not cure them with the code. ...
    52 replies | 2693 view(s)
  • DD4WH's Avatar
    08-21-2019, 08:11 PM
    Brian, thats excellent news! I am far from understanding the code by Warren Pratt from his wdsp lib, so playing around until the result is what we want is exactly the right way to find the optimal solution in this case...
    19 replies | 613 view(s)
  • DD4WH's Avatar
    08-20-2019, 07:30 PM
    Hi Brian, thats indeed strange. Thanks for your measurement effort, thats not possible here at my work bench :-). As you said, one block of 128 samples is fed into the audio chain, and one block is sent out. With...
    19 replies | 613 view(s)
  • DD4WH's Avatar
    08-20-2019, 07:23 PM
    @Blackaddr: could you point me in the right direction where I could add your register settings (in which file)? I tried to add them in my sketch in the setup, but no success, it seems to make no difference. //...
    52 replies | 2693 view(s)
  • DD4WH's Avatar
    08-20-2019, 07:49 AM
    Very interesting! It would be nice to know where and how exactly you changed the files (but maybe that will soon be incorporated in the next Teensyduino version?). I would just like to report my very similar...
    52 replies | 2693 view(s)
  • DD4WH's Avatar
    08-19-2019, 08:58 PM
    You are probably right, I now soldered the T4 and the audio board with very short wires and its still quite sensitive, I use a lower sample rate (and a lower MCLK freq) for the moment in order to be able to experiment....
    19 replies | 613 view(s)
  • DD4WH's Avatar
    08-19-2019, 08:46 PM
    Pete and FrankB, you saved my evening! :-) Thanks a lot for the code, works fine for the Teensy audio board and T4!
    5 replies | 366 view(s)
  • DD4WH's Avatar
    08-19-2019, 06:22 AM
    Hi Brian! yes, first I tried your convolution object with the T4 and it worked nicely! The reason why I put up this sketch was: * it is Stereo * it divides the processor load evenly between audio blocks * it...
    19 replies | 613 view(s)
  • DD4WH's Avatar
    08-17-2019, 06:44 PM
    To test T4 performance I extracted the fast convolution filtering code from my SDR and tested it with the Teensy 4.0 and the Teensy audio board. Both were connected with flying wires (MCLK with 100ohms series resistor)....
    19 replies | 613 view(s)
  • DD4WH's Avatar
    08-17-2019, 01:39 PM
    Hi! it seems it does not work properly with the library as it is at the moment. I used the SGTL5000 audio board, connected it to the T4.0 and used the guitar example. Additionally to the original example I added...
    3 replies | 129 view(s)
  • DD4WH's Avatar
    08-16-2019, 08:04 AM
    Thanks for your input! When using the DAC alone, it works perfectly both ways: either with SCL connected to GND (PLL mode) or SCL connected to pin 23 (using MCLK from the Teensy 4.0). But when I additionally...
    52 replies | 2693 view(s)
  • DD4WH's Avatar
    08-15-2019, 06:22 PM
    Oh, did not know that. I left SCL of the DAC unconnected. When testing with the Convolution object by DerekR I experienced strange crackling noises. Could it be that this is caused by this? I will try to connect...
    52 replies | 2693 view(s)
  • DD4WH's Avatar
    08-15-2019, 03:07 PM
    Thanks again for the hints! ADC works together with DAC ! Connections for documentation: Teensy 4.0 with ADC PCM1808 module (line-in Input), running simultaneously with the DAC PCM5102 (headphone output): ADC...
    52 replies | 2693 view(s)
  • DD4WH's Avatar
    08-15-2019, 02:02 PM
    Thanks for that hint! Is working now. Just for documentation for others to try: Teensy 4.0 and DAC PCM5102 module from AliExpress Vcc = Vin GND = GND FLT = GND SCL = floating BCK = BCK = pin 21 DIN = TX = pin...
    52 replies | 2693 view(s)
  • DD4WH's Avatar
    08-15-2019, 06:55 AM
    Could you post your sketch for using the PCM5102 with the Teensy 4.0? Or did you just use an example sketch? If yes, would be nice to know which one you used. Thanks a lot! Regards, Frank DD4WH
    52 replies | 2693 view(s)
  • DD4WH's Avatar
    08-15-2019, 06:53 AM
    DD4WH replied to a thread Bat detector in Audio Projects
    Hi Edwin, thanks a lot! I will think more about that! However, adding additional hardware for features already implemented (built-in SD card) is a bit annyoing, and I think I read that the built-in SD card is much...
    452 replies | 32276 view(s)
  • DD4WH's Avatar
    08-14-2019, 07:09 PM
    DD4WH replied to a thread Bat detector in Audio Projects
    well, then we will never know or solve the problem with the noise that you have . . .
    452 replies | 32276 view(s)
  • DD4WH's Avatar
    08-14-2019, 07:06 PM
    DD4WH replied to a thread Bat detector in Audio Projects
    Hi Corbee, it could well be that the 23kHz noise is associated with the wrong connection of the central pad which must be left totally unconnected in single ended mode. But we do not know if you do not have a closer...
    452 replies | 32276 view(s)
  • DD4WH's Avatar
    08-14-2019, 06:39 PM
    DD4WH replied to a thread Bat detector in Audio Projects
    Hi Corbee, as I stated, the spectrum is from 0 to 250kHz (500ksps sample rate !), you have to multiply the frequency axis by 10 ;-). Your spectrum looks good, except for the peak at 23kHz. How did you connect...
    452 replies | 32276 view(s)
  • DD4WH's Avatar
    08-14-2019, 05:49 PM
    DD4WH replied to a thread Bat detector in Audio Projects
    strange, I updated the spectrum, can you see it now? Its visible here . . .
    452 replies | 32276 view(s)
  • DD4WH's Avatar
    08-14-2019, 04:53 PM
    DD4WH replied to a thread Bat detector in Audio Projects
    Here is a spectrum of a recording with the ICS40730 made in Audacity: As you can see, the scale is from -70 to -90dB on the y-axis, so there is no pronounced noise at a certain frequency, its all below -70dBFS,...
    452 replies | 32276 view(s)
  • DD4WH's Avatar
    08-14-2019, 04:46 PM
    DD4WH replied to a thread Bat detector in Audio Projects
    Hi Edwin, sorry for being silent so long. I have some experience with the ICS40730 and can only say its the most powerful ultrasound MEMS I have ever seen . . . it can pick up ultrasound up to 160kHz and is highly...
    452 replies | 32276 view(s)
  • DD4WH's Avatar
    08-12-2019, 08:40 AM
    Hi Valeri, well thats explainable: * there are different options to use the oscillator chip Si5351: which clock output do you use? and which Xtal frequency did you install? These six different options alone...
    212 replies | 52990 view(s)
  • DD4WH's Avatar
    08-12-2019, 08:36 AM
    Hi FrankB, thanks a lot for your simulations of the input filter! I am a little puzzled about that difference in comparison to my simulations with ELSIE . . . Will have to think about that and try to simulate a...
    212 replies | 52990 view(s)
  • DD4WH's Avatar
    08-12-2019, 08:32 AM
    It will probably take us a while to account for the changes in Teensy 4.0. At the moment I am not sure whether it will compile and/or work with the T4. I do not own a T4 yet, but the order is already on its way to my...
    212 replies | 52990 view(s)
  • DD4WH's Avatar
    08-12-2019, 08:27 AM
    There have been several people with that plan. But as far as I know, nobody has published code for that. If you are interested in an SDR transceiver code, you might have a look at UHSDR (however, developed for the...
    212 replies | 52990 view(s)
  • DD4WH's Avatar
    08-12-2019, 08:23 AM
    you seem to confuse the "Teensy SDR" with the "Teensy Convolution SDR". The former is using all 16-bit integer math and uses blocks as in the audio library. So your proposed way of using it should perfectly work! ...
    212 replies | 52990 view(s)
  • DD4WH's Avatar
    07-15-2019, 05:56 AM
    As far as I can see, there is no need for such a large (and processor-intense) FFT. Of course the T4 could help you, but I am pretty sure that by reducing the load you can do that on a T3.6 Your visualization only...
    35 replies | 9699 view(s)
  • DD4WH's Avatar
    07-08-2019, 08:42 AM
    Hi gohlhausen, thanks for your work! Did you test, how your FFT performs if applied to audio? In my experience, when used for convolution (FFT --> complex-multiply with filter mask --> inverse FFT), the fixed...
    35 replies | 9699 view(s)
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About DD4WH

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About DD4WH
Location:
Central Europe
Interests:
Software Defined Radio, Digital Signal Processing, Bat detection & bioacoustics

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Fast Convolution Filtering with Teensy 4.0 and audio board 08-21-2019 08:50 PM
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10-25-2015