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Type: Posts; User: Bill Glass

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  1. OK. What a pity. Thanks!

    OK. What a pity. Thanks!
  2. More specifically: I want to put the code I...

    More specifically:

    I want to put the code I have just displayed in a Teensy sketch called asrc.ino.

    1. Executing asrc.ino, how can I get those 128 inblock samples when they arrive from the...
  3. Well, I still would like to find a way to...

    Well, I still would like to find a way to evaluate my polynomial polyphase asrc on the Teensy.

    My conditions (due to my limited programming knowledge) are:

    1. Don't modifying or add new...
  4. Well, thanks but all of that is a little bit over...

    Well, thanks but all of that is a little bit over my head. I'm not really a software guy. I'm more into signal processing and C programming to make things work. I was hoping to use my C functions in...
  5. Unrolled 4 times by hand -> better 5.5->4.1...

    Unrolled 4 times by hand -> better 5.5->4.1 cycles/tap. Thanks for the tip.
    For the PRAGMA, I don't know how to do that. My code is in the Arduino IDE sketch directory and I let the IDE...
  6. OK. Can't explain why I get 5.5 cycles/tap...

    OK. Can't explain why I get 5.5 cycles/tap otherwise. Thanx
  7. Makes me wonder. Does the instruction,...

    Makes me wonder. Does the instruction, multiply_accumulate_32x32_rshift32_rounded execute in 1 cycle?
  8. OK. Guess those 32x16 multiplies in dspinst.h are...

    OK. Guess those 32x16 multiplies in dspinst.h are there for lower Teensy versions. In this function, I'm executing a FIR with 89 taps. I'm getting 484/89 or 5.4 cycles/tap including overhead stuff....
  9. Continuing on a little bit. Why, in my code...

    Continuing on a little bit. Why, in my code below, do I not improve my cycles consumed when switching from multiply 32x32 to 32x16? See #ifdef __ARM_ARCH_7EM__.



    int32_t sinxcalc_fix(int32_t...
  10. :) Thanx for the info

    :) Thanx for the info
  11. No problem. I have no intention of touching any...

    No problem. I have no intention of touching any libraries. I am a simple customer who reports bugs to those who manage them.

    Apparently there are few people who develop offline. I find that it's...
  12. dspinst.h problem with...

    dspinst.h problem with multiply_accumulate_32x32_rshift32_rounded(int32_t sum, int32_t a, int32_t b) and others

    Seems to be a missing 0 for return sum + ((((int64_t)a * (int64_t)b) + 0x8000000) >>...
  13. Well, I integrated my srconv and associated...

    Well, I integrated my srconv and associated fuctions in a Teensy *.ino sketch for now. Input samples from program memory using AudioPlayMemory object and sending srconv output buffers to...
  14. Hello Alex Comments to: Your answer...

    Hello Alex

    Comments to:

    Your answer Question 1. What can the AudioInputSPDIF3 connect to unless it is in master mode (synchronized with the Teensy clock)? I don't really see the use of it....
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    Actually the current asrc that you have...

    Actually the current asrc that you have implemented has a very low distortion and I have no intention to try and replace it. I am only trying to validate my studies using real hardware on an asrc...
  16. and: 26793

    and: 26793
  17. New project to verify an asrc using polynomial approximations for its coefficients

    Hello. I want to start a new project. I had simulated a floating point software asynchronous sample rate converter in C & Matlab with some satisfying results for +-250 ppm adjustments.

    I am using...
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    Thank you for all your answers! I wanted to...

    Thank you for all your answers!

    I wanted to know if there are really 20481 (16-bit, 32-bit?) coefficients?
    I'm asking all these questions because I am very interested in the subject.

    The ASRC...
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    Yes. I found that it's the inverse of the THD+N...

    Yes. I found that it's the inverse of the THD+N (90dB is good for Sinad and -90dB for THD+N). I always thought my tool was measuring THD+N but it's really measuring SINAD.
    ...
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    SINAD ? A good or bad method for evaluating the...

    SINAD ?
    A good or bad method for evaluating the quality of a sample rate converter?
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    If I correctly understood your explanations: ...

    If I correctly understood your explanations:

    My understanding is:

    AsyncSpdif
    ----------------
    delay_line_length=68 (for half filter length of 34)
    Ncoefs=20481
    983 MACS/sample...
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    @MarkT @alex6679 I haven't yet looked at...

    @MarkT @alex6679

    I haven't yet looked at https://holometer.fnal.gov/GH_FFT.pdf but I also evaluate an audio wav file with a C tool. The tool does not do FFT analysis but rather calculates energy...
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    OK. I will look at it. However I used the same...

    OK. I will look at it. However I used the same method for analyzing the recorded samples from the audio and the Async spdif inputs.
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    You're welcome. As you see, the results seem...

    You're welcome. As you see, the results seem better for the spdif input. However, if I understand correctly, the Teensy processes 16-bit data which will not show much information on the noise floor...
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    thanks. here's the results on the analog signal....

    thanks. here's the results on the analog signal. I think I recorded it with a lower volume than the SPDIF one I showed you in my last post.

    26692
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    Is the results what you expected? I hope so. ...

    Is the results what you expected?

    I hope so.

    They sure look good to me.

    I will probably get a transmitter optical connector for my box as well as the same company makes an FCR684205(R&T). My...
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    I had too much volume on my TV music player and I...

    I had too much volume on my TV music player and I switched to external 5V supply on Teensy Vin instead of power from the USB. It looks good now. Here's the input wav file, and the SD card recorded...
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    For the 10kHz without recording to the SD but to...

    For the 10kHz without recording to the SD but to the USB, same " really not look good" spectrum.
    But, with 10kHz tone on the audio input to the adapter and output to the USB, result was OK.

    26675
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    My results using optical spdif connector...

    My results using optical spdif connector recording a 10 kHz sine wav coming out of my TV audio player OR my PC via an optical cable.


    #include <Bounce.h>
    #include <Audio.h>
    #include <Wire.h>...
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    Thank you. I received the optical connecter...

    Thank you. I received the optical connecter today. I tried to hook it up but there seems to be a compatability issue between the spdfin pin 15 of the Teensy 4.0 and the audio adapter. I need the...
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    Hello Alex I am still waiting for that optical...

    Hello Alex

    I am still waiting for that optical spdif connector to evaluate the quality of the received signal from my TV thru the Teensy spdif asrc input. I now have a reliable method for...
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    OK, no more hiccups. Got me what seems to be a...

    OK, no more hiccups. Got me what seems to be a good method for analyzing Teensy digital audio after ADC. Thanks for your help! Attached are the spectrums of input to Audacity player sig.jpg, and SD...
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    BTW, I'm the BUG. Yes, indeed. Quick test with...

    BTW, I'm the BUG. Yes, indeed. Quick test with same program, I set m to 100 blocks (301.7ms means 103.7 blocks) and I set AudioMemory(128). It happens now. I'll go look for hiccups tomorrow.

    Thanx!
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    There is a problem with the length of the...

    There is a problem with the length of the recording queue. If (queue1.available() >=12) it never happens. 12 corresponds to 35msec of 44100Hz samples. According to the Recorder example sketch, the...
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    Yes, but there were, worst case, 22msec even with...

    Yes, but there were, worst case, 22msec even with those last hiccups I showed. According to the comment in the record example, the buffer object can tolerate 301.7 msec. from time to time.
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    Observations: 1. After studying the forum, there...

    Observations:
    1. After studying the forum, there seems to be a general problem concerning reliable recording of audio on the SD card even if reasonable average SD write latency is obtained (<2ms)....
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    And my next day discovery concerning the previous...

    And my next day discovery concerning the previous spectrum reveals occasional hiccups in that 128-sample recording queue.

    26647
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    I powered up myTeensy and audio adapter with 5V...

    I powered up myTeensy and audio adapter with 5V on Vin instead of via the USB cable. Better but not perfect. I'm curious to find out how it will look when I get that spdif input interface.


    ...
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    And the winner is 22msec but occasionally with...

    And the winner is 22msec but occasionally with normal values of 1.7msec.
    I recorded a linein signal at 172.2256Hz (period of 256 samples at 44.1kHz) and it looks pretty ratty. I didn't have this...
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    Ah, that corresponds precisely with what I'm...

    Ah, that corresponds precisely with what I'm doing. Recording every 2 audio blocks to the SDCard. Sounds like a bug? Here's my code:
    #include <Bounce.h>
    #include <Audio.h>
    #include <Wire.h>...
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    Yes, as soon as I get that connector for the...

    Yes, as soon as I get that connector for the spdif optical cable, I will test it and publish the results. I am a little bit pessimistic about what may happen between my 24-bit sine wav file on my USB...
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    VERY IMPRESSIVE! I ordered the connector you...

    VERY IMPRESSIVE! I ordered the connector you suggested and I will try it out, recording(via an SDCard on my audio adapter) a sine wave from a wav file stored on my TV audio player. I don't know how...
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    Hello. Thanx for the info. Yes, I will try that....

    Hello. Thanx for the info. Yes, I will try that. If it works OK with the Teensy Async spdif input, I will replace my audio connector input with it. It's for my AGC/Compressor box (see below). How...
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    I would like to try this example too. Can you...

    I would like to try this example too. Can you please explain the hardware and schematic I need to interface my optical cable to my Teensy 4.0 and audio adapter. Thanks.
  45. Final version: // Record sound as raw data...

    Final version:


    // Record sound as raw data to a SD card
    //
    // Requires the audio shield:
    // http://www.pjrc.com/store/teensy3_audio.html
    //
    // 1 pushbutton needs to be connected:
    // ...
  46. OK, I have an idea on how I can compare processor...

    OK, I have an idea on how I can compare processor usage of myTeensyBiq vs. the standard audio library biquad.

    1. I know that I can use the command, biquad.processorUsage() to have the the % usage...
  47. 1.OK got it. 2.Last question of the (next)...

    1.OK got it.

    2.Last question of the (next) day. I was able to measure the execution cycles/sample wit myTeensyBiq() because I have access to the beginning and end execution times but not so with...
  48. See myTeensyBiq() in the code which I just sent...

    See myTeensyBiq() in the code which I just sent using multiply_accumulate_32x32_rshift32_rounded() & described in dspinst.h. I get better results than filter_biquad.cpp (THD=90dB instead of 72),...
  49. I have recorded biquad outputs to SDCard instead...

    I have recorded biquad outputs to SDCard instead of thru the USB interface to avoid any additional processing to them.
    Here is my code and results (cycles corrected for calculation error).

    What...
  50. Thanx. Yeah, I've learned a lot from y'all! It's...

    Thanx. Yeah, I've learned a lot from y'all! It's a good forum!
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