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  • DD4WH's Avatar
    10-07-2019, 07:28 PM
    Installed Ardunio 1.8.10 and Teensyduino 1.48 Same effect: if I compile with "Optimize: smallest code", the script does not run properly when I set the limit above 20: it only prints out "Before writing" and bricks...
    10 replies | 159 view(s)
  • DD4WH's Avatar
    10-07-2019, 03:30 PM
    thanks for testing! Tested it again to be sure (with while(!Serial) :-), but same problem occurs here: if I use "Optimize: smalles code" it works with 20, but not with 50 (prints out "Before writing", but nothing...
    10 replies | 159 view(s)
  • DD4WH's Avatar
    10-07-2019, 01:52 PM
    @manitou: thanks for the hint! However, it did not help. The real problem I had was that in the Arduino compiler setting I had "optimize: smallest code" (which I did not realize . . .). That produced code that would...
    10 replies | 159 view(s)
  • DD4WH's Avatar
    10-06-2019, 03:28 PM
    Thanks! I thought a delay(1000) was enough . . . ? And why is the Serial output dependent on the number of EEPROM adresses?
    10 replies | 159 view(s)
  • DD4WH's Avatar
    10-06-2019, 03:13 PM
    I run into problems with EEPROM.h use with the Teensy 4.0. I would like to use the EEPROM to save about 800bytes. The code below runs for (about) the first 20 EEPROM adresses, but fails with more. Additionally, the...
    10 replies | 159 view(s)
  • DD4WH's Avatar
    10-05-2019, 02:46 PM
    Dont worry about the update rate: you can do the following: for every block of 128samples: * lowpass @689Hz * take every 32th sample --> so you get 4 new samples for every new audio block arriving * perform FFT256...
    63 replies | 10872 view(s)
  • DD4WH's Avatar
    10-05-2019, 02:37 PM
    DD4WH replied to a thread fft overlap add in Audio Projects
    maybe you would also like to have a look here for an example: Brian has implemented such a convolution object, however based on a 1024-point-FFT: ...
    6 replies | 103 view(s)
  • DD4WH's Avatar
    10-05-2019, 10:47 AM
    For those interested, this is the audio flow in software for demodulation of stereo wideband FM. If you have any suggestions for improvement, I will be very happy to hear about that! Also those interested in helping to...
    229 replies | 56041 view(s)
  • DD4WH's Avatar
    10-05-2019, 10:08 AM
    The Teensy Convolution SDR goes 4.0 Here, it demodulates FM stereo at 256ksps sample rate using the processor intense atan2 function with the double precision FPU of the Teensy 4.0. Processor load is now about...
    229 replies | 56041 view(s)
  • DD4WH's Avatar
    10-02-2019, 01:09 PM
    Thanks for all your hints on getting rid of the crackle noise. I finally succeeded by using RF perf board with a ground plane and set up the Teensy 4.0 and DAC PCM5102a and ADC PCM1808 on it. See here for the...
    71 replies | 4897 view(s)
  • DD4WH's Avatar
    10-02-2019, 01:06 PM
    Hi Brian, thanks for your measurements, they provide nice insight! And I would not have been able to do similar things! I managed to fix my crackling noise by using a proper hardware setup on a proper groundplane,...
    23 replies | 1096 view(s)
  • DD4WH's Avatar
    09-30-2019, 11:41 AM
    Maybe I misunderstood your aim . . ., but if you add a GPS module, you will have a very accurate RTC! You do not need an extremely expensive TCXO then? The Teensy 3.2 already has a builtin RTC, you only need a 32768kHz...
    14 replies | 161 view(s)
  • DD4WH's Avatar
    09-30-2019, 11:36 AM
    BTW, a good starting point could be: 1.) take the AudioGrabber object by DerekR as-it-is for the FFT256 at standard sample rate 2.) modify the AudioGrabber object (include the code for lowpass filtering and...
    63 replies | 10872 view(s)
  • DD4WH's Avatar
    09-30-2019, 10:01 AM
    Your two points are exactly the way to go. BTW, point 2) is in fact the ZoomFFT ;-). You do not need two ADCs with different sample rates. Just use one ADC with 44.1kHz, and do this: 1.) normal 256-point-FFT with...
    63 replies | 10872 view(s)
  • DD4WH's Avatar
    09-30-2019, 06:56 AM
    Hi, sounds interesting, that "logarithmic FFT". As far as I can see, it must be quite similar to the "ZoomFFT"!? If you use longer input periods, your sample rate would have to be lowered and you would have to...
    63 replies | 10872 view(s)
  • DD4WH's Avatar
    09-27-2019, 10:45 PM
    DD4WH replied to a thread Teensy SDR help in Audio Projects
    This should be pretty close to what you are looking for: https://github.com/DD4WH/Teensy-SDR-Rx Have a close look at the pdf first of all. All the best, Frank DD4WH
    2 replies | 92 view(s)
  • DD4WH's Avatar
    09-27-2019, 06:32 PM
    There is now a small red symbol flashing in the same rythm with the Morse code tones when CW thresh is properly adjusted (it should not react to noise, but to the Morse code: this is essential for proper decoding). Also...
    229 replies | 56041 view(s)
  • DD4WH's Avatar
    09-27-2019, 09:56 AM
    Morse code (CW) decoding is now available in the Teensy Convolution SDR. We have implemented the decoder version supplied by Loftur (thanks a lot for putting that into the public domain!...
    229 replies | 56041 view(s)
  • DD4WH's Avatar
    09-16-2019, 04:30 PM
    Hi Jim, sorry, there is no wiring diagram, but there is plenty of information on the Internet for low-IF SDRs like this. There is some more information in the pdf to the Teensy SDR...
    229 replies | 56041 view(s)
  • DD4WH's Avatar
    09-16-2019, 04:26 PM
    I would recommend to resolder all of your solder joints underneath the Teensy under magnifying glasses or a stereo microscope. I can see some partly unsoldered or looking "cold", eg. pins 17, 18, 21. All the...
    13 replies | 182 view(s)
  • DD4WH's Avatar
    09-16-2019, 02:27 PM
    Hi Peter, now thats strange, did you use the latest version from my github? It has the following in line 191 which should work: extern "C" { void sincosf(float err, float *s, float *c); }
    229 replies | 56041 view(s)
  • DD4WH's Avatar
    09-11-2019, 07:15 PM
    I am not sure about the requirements of a VOX application, but I think a signal level measurement should be sufficient. You will not be that far from the mic in order to make reliable communication? So I think a simple...
    8 replies | 1455 view(s)
  • DD4WH's Avatar
    09-11-2019, 07:06 PM
    No, unfortunately not. I spent many hours on that and have not succeeded in performing reliable I2S In and Out with the Teensy 4.0. The very same hardware (Teensy Audio Shield, PCM1808 & PCM5102) with the T3.6 work...
    71 replies | 4897 view(s)
  • DD4WH's Avatar
    09-02-2019, 08:52 PM
    I have been trying to use the Teensy 4.0 with the PJCR Teensy Audio shield to get I2S audio input and output. The audio shield was soldered with very short wires (< 2cm) and 100 Ohms series resistor in MCLK. photo...
    0 replies | 117 view(s)
  • DD4WH's Avatar
    09-01-2019, 07:41 PM
    As far as I understand, it is indeed necessary in order to cancel out the opposite sideband in SSB. But if I understand it correctly, in the Convolution filter, the complex filtering of both channels already does the...
    16 replies | 559 view(s)
  • DD4WH's Avatar
    09-01-2019, 03:14 PM
    Hi Derek, thats very interesting stuff! For me as a non-engineer, there are a few points that are not easily understandable: 1.) SSB: Where is the Hilbert transform in Fast convolution filtering in the frequency...
    16 replies | 559 view(s)
  • DD4WH's Avatar
    09-01-2019, 11:18 AM
    I have to apologize, I did not read your post well: you wanted PCBs, here they can be purchased: https://aisler.net/daba/are-ssr-1/are-ssr-2 You can also contact Dante via this thread: ...
    229 replies | 56041 view(s)
  • DD4WH's Avatar
    09-01-2019, 11:02 AM
    It is all here: https://github.com/do7jbh/SSR-2 Dante DO7JBH has his own software that runs on his hardware, but the Teensy Convolution SDR also runs on his hardware.
    229 replies | 56041 view(s)
  • DD4WH's Avatar
    08-30-2019, 06:44 AM
    Unfortunately, I have to say that the crackling noise returned. I made numerous attempts to cure that by returning to sample rate 44100sps, by inserting different resistor values into the MCLK line, by changing the...
    71 replies | 4897 view(s)
  • DD4WH's Avatar
    08-29-2019, 07:45 PM
    Hi Derek, I am really impressed, that seems a really nicely structured SDR layout! I will soon make an attempt to try it out! However, when compiling, "Streaming.h" is missing. Where can I find that? All the...
    16 replies | 559 view(s)
  • DD4WH's Avatar
    08-29-2019, 06:16 PM
    @bicycleguy: looks good! My working setup is very similar! How high can you tune up the sample rate until your setup gives distorted audio?
    71 replies | 4897 view(s)
  • DD4WH's Avatar
    08-29-2019, 06:14 PM
    Just one thing to add: we have exactly the same phenomenon of I2S synch error with the following hardware combinations for our Software Defined Radio Software UHSDR: STM32F4 & WM8731 STM32F7 & WM8731 STM32H7 &...
    16 replies | 275 view(s)
  • DD4WH's Avatar
    08-29-2019, 06:06 PM
    @Blackaddr: Thanks a lot! After hours of searching for my issue, I resoldered all connections and now the T4 & audio shield combination seems to work reliably up to 120ksps sample rate. With higher sample rates, there...
    71 replies | 4897 view(s)
  • 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...
    23 replies | 1096 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. ...
    71 replies | 4897 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...
    23 replies | 1096 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...
    23 replies | 1096 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. //...
    71 replies | 4897 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...
    71 replies | 4897 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....
    23 replies | 1096 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 | 437 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...
    23 replies | 1096 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)....
    23 replies | 1096 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 | 206 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...
    71 replies | 4897 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...
    71 replies | 4897 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...
    71 replies | 4897 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...
    71 replies | 4897 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
    71 replies | 4897 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...
    527 replies | 36085 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 . . .
    527 replies | 36085 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...
    527 replies | 36085 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...
    527 replies | 36085 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 . . .
    527 replies | 36085 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,...
    527 replies | 36085 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...
    527 replies | 36085 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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Teensy 4.0 and EEPROM.h problem 10-07-2019 07:28 PM
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10-25-2015