Forum Rule: Always post complete source code & details to reproduce any issue!

Search:

Type: Posts; User: DerekR

Page 1 of 3 1 2 3

Search: Search took 0.00 seconds.

  1. Replies
    203
    Views
    49,199

    Hi Frank, I am not familiar with any "rule of...

    Hi Frank,
    I am not familiar with any "rule of thumb" regarding length of FFT buffers, and am not familiar with any Brogerding reference. (FWIW -I might just mention that I taught Signal...
  2. Replies
    203
    Views
    49,199

    Yes I'm doing overlap-and-add, and the zero...

    Yes I'm doing overlap-and-add, and the zero padding is for that very purpose. You are probably aware that when doing frequency domain convolution (via FFT) of two time functions of lengths P and Q...
  3. Replies
    203
    Views
    49,199

    I have never seen a reference to what happens...

    I have never seen a reference to what happens after a spectral rotation in the FFT of a zero padded data set. What happened was that when I tried it in hardware I noted a sign change in successive...
  4. Replies
    38
    Views
    1,209

    Paul - I'm delighted to report that your efforts...

    Paul -
    I'm delighted to report that your efforts and suggestions have been 100% successful (with the Teensy in Master mode)! After adding the 220R resistor to the MCLK line, and using your updated...
  5. Replies
    203
    Views
    49,199

    You are absolutely correct. My bad! Of course...

    You are absolutely correct. My bad! Of course you rotate the FFT data. Brain fart!
    I should say that because we are working on a length N data buffers in a zero padded length 2N FFT, there is a...
  6. Replies
    203
    Views
    49,199

    Frank - quick reply: 1) Yes - Hans Summer at QRP...

    Frank - quick reply:
    1) Yes - Hans Summer at QRP Labs was the inspiration for the SI5131 mod, but I couldn't find any published code at the time I wrote my own. I certainly confirm Hans'...
  7. Replies
    203
    Views
    49,199

    Hi people, I've just converted my SI5351 tuner...

    Hi people,

    I've just converted my SI5351 tuner clock to direct quadrature generation without need for a divide by 4 Johnson counter. The I and Q outputs are on CLK0 and CLK1. It generates a very...
  8. Replies
    38
    Views
    1,209

    Paul - Blackaddr and I found that the problem was...

    Paul - Blackaddr and I found that the problem was much, much worse when I2S input/output is running... Like you I was able to run Audio stuff - with a few errors - without I2S...

    The reason...
  9. Replies
    38
    Views
    1,209

    I've been working on this problem for the past...

    I've been working on this problem for the past few days. I bought a cheapo logic analyzer ($12 on Amazon) and it has been amazingly helpful in working out exactly what is going on!
    Here are my...
  10. Replies
    38
    Views
    1,209

    I thought we were out of the woods, but as I...

    I thought we were out of the woods, but as I hinted last night there are problems still with the added resistors when another device is added to the I2C bus!

    In my case when I added an Adafruit...
  11. Replies
    38
    Views
    1,209

    You are absolutely correct. Apologies to all -...

    You are absolutely correct. Apologies to all - I can't count...:D The Wire library data packets sent from the master (Teensy) were correct all along, and it was the codec's ACK/NACK bit that was...
  12. Replies
    38
    Views
    1,209

    Here's an application note about choosing the...

    Here's an application note about choosing the value of I2C pullup resistors [URL= http://www.ti.com/lit/an/slva689/slva689.pdf[/URL]. The higher the pull-up, the slower the risetime because of...
  13. Replies
    38
    Views
    1,209

    Fantastic! Adding the two 220R resistors on the...

    Fantastic! Adding the two 220R resistors on the SDA and SCL lines fixed the problem, and the WM8731 is now working on both the T3.6 and T3.2s without errors. It is working with the Audio library...
  14. Replies
    38
    Views
    1,209

    I'm off to add 220R resistors right now, more...

    I'm off to add 220R resistors right now, more later... Incidentally, I noticed the other day that the T3.6 worked for a few hours IF (and only IF) I had the 'scope probes connected to the SCL and...
  15. Replies
    38
    Views
    1,209

    But the little Wire sketch has no I2S... By the...

    But the little Wire sketch has no I2S... By the way I think you did a nice job with BALibrary. I will certainly use it when I get this issue resolved.
  16. Replies
    38
    Views
    1,209

    I2C problems with Teensy 3.6 and WM8731 codec

    For the past week or so I have been trying unsuccessfully to use a WM8731 codec with a T3.6. Others are having the same problem and it is actively being discussed in another thread. I have started...
  17. Replies
    33
    Views
    1,851

    I am about to post a new thread about the I2C...

    I am about to post a new thread about the I2C problem! I believe I might have gotten to the bottom of it, and if it is true, there is a bug in the Wire library! The WM8731 works very well with a...
  18. Replies
    33
    Views
    1,851

    Well, the good news is that I have the WM8731...

    Well, the good news is that I have the WM8731 chip working interfaced directly to the Teensy 3.6. It's working with BALibrary, but I still no have luck just with the Audio Lib WM8731 handler alone....
  19. Replies
    33
    Views
    1,851

    Hi everybody, I've been away from the forum for...

    Hi everybody,
    I've been away from the forum for many months for health reasons, and because I was unable to solve the audio board quadrature bug in which the two channels are randomly offset by a...
  20. Bob, I have continued to be plagued by this...

    Bob,
    I have continued to be plagued by this bug, and after a year of trying have still not found a true solution. It sure plays hell with my own SDR work, and in ultrasonic imaging work, where...
  21. Replies
    29
    Views
    11,802

    That's a great idea! I'm still having the...

    That's a great idea! I'm still having the problem and am struggling with having to solder the chips in suspended on 30AWG wire. Hardly an elegant robust solution. A potential problem is I also use...
  22. AudioEffectDelayExternal and ILI9341 display not compatable

    I've been away from the forum for several months, but working day and night on a compact Teensy 3.6 based music processor for real-time concert performance. Things have been going great until...
  23. Now I recall where I got the idea as to how fast...

    Now I recall where I got the idea as to how fast the latest rffts are. I have been using arm_rfft_fast_f32() in my new Audio block STFT based channel-vocoder (512 channels max) for electronic music...
  24. I did the timing comparisons for N = 256, 512,...

    I did the timing comparisons for N = 256, 512, and 1024, directly and the improvement seems to be nowhere as great as I recall from a couple of weeks ago.
    T3.6 at 180MHz.
    Here's the quickie sketch...
  25. I'll do a direct timing comparison on the length...

    I'll do a direct timing comparison on the length 256 and 1024 versions and get back tomorrow...

    BTW - the arm_rfft_q15() and arm_rfft_q31() in the more recent arm_math that I am using with...
  26. @WMXZ Hehehe - completely off-topic :D, but I...

    @WMXZ
    Hehehe - completely off-topic :D, but I accept the challenge, we will meet at dawn tomorrow behind the barn and settle this thing once and for all! You've got this ancient academic on one of...
  27. Sustituting arm_rfft_q15() into the Audio Library FFT functions?

    Has anybody thought about (or already completed) substituting the arm_rfft_q15() real FFT function as the workhorse in the Audio Library FFT blocks? I have been using it in several projects...
  28. Replies
    13
    Views
    2,431

    I was very curious to see how my AudioPLL block...

    I was very curious to see how my AudioPLL block actually did on tracking the mosquito wing data, so I modified it to stream the input data and the synthesizer output to the Serial Plotter, and...
  29. Replies
    13
    Views
    2,431

    @Wicky21 I just took a look at your data. I...

    @Wicky21
    I just took a look at your data. I think it might not be quite as you imagine it! It might be quite interesting from an entomological point of view :D but this particular data set is...
  30. Replies
    13
    Views
    2,431

    The documentation will tell you what the two...

    The documentation will tell you what the two channels on the Serial Monitor output are in "analysis" mode: the first is the output waveform from the synthesizer, the second is the instantaneous...
  31. Replies
    13
    Views
    2,431

    Why don't you simply play your .wav file through...

    Why don't you simply play your .wav file through the PLL, watch the output on the Serial Monitor and report back here what happens.
  32. Replies
    101
    Views
    28,642

    It simply is computing the magnitude of the FFT. ...

    It simply is computing the magnitude of the FFT. All FFT's are a relationship between "complex" mathematical time and frequency domains. That is they require complex numbers for the time signal...
  33. Replies
    16
    Views
    2,222

    I have just posted the AudioPLL stuff in its own...

    I have just posted the AudioPLL stuff in its own thread here
  34. Replies
    13
    Views
    2,431

    An Audio Phase-Locked-Loop (PLL) Block

    I'm pleased to post a new Audio Block that implements a real-time phase-locked-loop for use with the Teensy Audio Board. The necessary files are contained in the AudioPLL.zip file here: 11579
    ...
  35. Replies
    16
    Views
    2,222

    Latest update: 1) The quadrature input Audio...

    Latest update:
    1) The quadrature input Audio Board version has been up-and-running all weekend. It's ready to go.

    2) The single-channel input version, which should be more useful to...
  36. Replies
    16
    Views
    2,222

    Here's the MATLAB code as requested ...

    Here's the MATLAB code as requested

    %--------------------------------------------------------------------------
    % Prototype for Teensy 3.x Phased-locked-loop (PLL) - simulation
    % Derek Rowell...
  37. Replies
    16
    Views
    2,222

    Good news! Yesterday I finally got the int16...

    Good news! Yesterday I finally got the int16 version debugged and working, and it works beautifully - just as well as my MATLAB simulation. There's just one little "teensy""problem: every 10 secs...
  38. Replies
    16
    Views
    2,222

    @Jacob2, No, it's not quite ready yet. For both...

    @Jacob2,
    No, it's not quite ready yet. For both you and Wicky21, I'll PM you both about what is going on with me and I'm sure you'll understand.
    The problem is in the integer version of the fast...
  39. @Wicky21 I took a listen and did some analysis...

    @Wicky21
    I took a listen and did some analysis in MATLAB on your .wav file, and it's no wonder that my method (and probably many other methods) will not work on your data!

    1) The audio is so...
  40. Replies
    16
    Views
    2,222

    I have the int16 version ready to post - except...

    I have the int16 version ready to post - except for one little "bug" that I hadn't noticed before: when it locks to a sinusoid the reported phase error is a constant (not zero) that is proportional...
  41. Replies
    16
    Views
    2,222

    Unfortunately I don't have a functional T3.2...

    Unfortunately I don't have a functional T3.2 anymore!

    I am working on the PLL for the same purpose as you, but specifically for electronic music analysis/synthesis. I am, however, spread...
  42. Replies
    16
    Views
    2,222

    Yes, I have had it running in several forms, and...

    Yes, I have had it running in several forms, and am just in the process of converting to an audio block PLL for real time-processing. However, I'm focussing on the T3.6 these days and haven't tried...
  43. New Code for Multiple Peaks - First Pass

    I have included my first pass at detecting and reporting multiple spectral peaks in the magnitude spectrum. It appears to be working well. The code is located here: 11481, and contains both 256...
  44. @Wicky21, It is definitely not "nice" to write a...

    @Wicky21,
    It is definitely not "nice" to write a nasty PM calling me "rude", when I have already spent several hours writing code specifically for you! I most certainly do not appreciate that! ...
  45. Replies
    17
    Views
    4,663

    Wicky21, It's not generally useful to expect...

    Wicky21,
    It's not generally useful to expect forum members to provide code to solve your problems. When you have a problem you should take the time to solve it, and you will learn a lot in the...
  46. Replies
    17
    Views
    4,663

    Decimation is very simple (without filtering)...

    Decimation is very simple (without filtering) simply take every nth sample in the input stream. I don't have a block to do this, but it should be trivial to write. Simply accumulate n input...
  47. Hi Brian, The Teensy itself doesn't have I2S...

    Hi Brian,
    The Teensy itself doesn't have I2S ports. The I2s inputs go directly into the codec on the audio board. So no, I didn't produce a digital I2s quad pair, I used an external function...
  48. Bug: Audio board I2S input data randomly out of sync after program reload

    This is an issue originally raised by DD4WH here, and expanded by me in posts #30 and #31 of that thread. After spending several days analyzing the issue and trying to find a fix or work-around I...
  49. As promised here is the code to demonstrate the...

    As promised here is the code to demonstrate the bug.
    Main sketch:

    // ------------------------------------------------------------------------------------------
    // TestPhaseError.ino ...
  50. Frank & Brian, I know I'm late to the party, but...

    Frank & Brian,
    I know I'm late to the party, but I want you to know that I am having the same problem with corresponding samples in data blocks from the I2S input apparently getting out of sync. ...
Results 1 to 50 of 115
Page 1 of 3 1 2 3