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  • DD4WH's Avatar
    Today, 01:38 PM
    :-) Well, it is a matter of definition of your goals! You mention three different of your goals in this thread: * pitch shifting * playback rate adjustment * crunchy and lovely audio effects All of those...
    12 replies | 156 view(s)
  • DD4WH's Avatar
    Today, 11:31 AM
    In the context of Software Defined Radio dealing with analytical (complex) signals, builders often use an IF at exactly samplerate-divided-by-4, ie. in your case 192ksps / 4 = 48kHz Then you are able to use a...
    9 replies | 141 view(s)
  • DD4WH's Avatar
    09-08-2020, 07:14 PM
    I am not at all familiar with FAUST, but by looking at the webpage it seems that there are things that can be very easily done with a T4.1 (all the filtering stuff) and more complex/demanding things (pitch shift --> CPU...
    6 replies | 207 view(s)
  • DD4WH's Avatar
    09-08-2020, 07:00 PM
    Could you specify your project and the kind of DSP you are planning? Otherwise there is no chance anyone could help you with an idea.
    6 replies | 207 view(s)
  • DD4WH's Avatar
    09-08-2020, 06:28 PM
    ??? Could you be a little more specific in your question? I think the T4.1 is more than capable of doing complex DSP.
    6 replies | 207 view(s)
  • DD4WH's Avatar
    09-08-2020, 11:54 AM
    Bob Larkin provided very nice code for an Audio Equalizer (https://forum.pjrc.com/threads/60928-Audio-Equalizer-using-FIR?highlight=audio+equalizer), which I implemented as a 9-band graphical EQ in the latest version of...
    550 replies | 90835 view(s)
  • DD4WH's Avatar
    09-04-2020, 09:05 AM
    Yes, the Malahit is a nice receiver, but unfortunately closed source. If you port the software to the STM32F7 or H7, please keep it open source and it would be very nice if you posted a link to the software source...
    550 replies | 90835 view(s)
  • DD4WH's Avatar
    09-04-2020, 07:00 AM
    Yes. At the moment it is programmed like that. Synch is not a problem, because both, the ADC and the DAC use the same master clock MCLK provided by the Teensy. Paul, did you already build a Teensy Convolution SDR? If...
    550 replies | 90835 view(s)
  • DD4WH's Avatar
    08-30-2020, 05:43 PM
    Not sure what you mean exactly? What are "valid channels"? Do you want an automatic frequency scan search for stations and save their frequencies in memory? That is not implemented at the moment. 73 de Frank
    550 replies | 90835 view(s)
  • DD4WH's Avatar
    08-30-2020, 05:41 PM
    I hope, the new version solves this problem. 73 Frank
    550 replies | 90835 view(s)
  • DD4WH's Avatar
    08-30-2020, 12:42 PM
    Thanks for pointing me to that, You are right, I built that bug. Will try to solve that this evening.
    550 replies | 90835 view(s)
  • DD4WH's Avatar
    08-30-2020, 12:33 PM
    Bill, I tried to exactly reproduce the situation you described: * 50 Ohms resistor on the antenna input So, the spectrum looks similar, BUT: the birdies are very very low signal strength. the overall noise...
    550 replies | 90835 view(s)
  • DD4WH's Avatar
    08-29-2020, 08:53 PM
    Yes, fully agreed! :-) AM mediumwave stations do not pose problems any more here in Central Europe, because most countries have shut down all or many of their transmitters! (eg. Germany, the Netherlands, France,...
    550 replies | 90835 view(s)
  • DD4WH's Avatar
    08-29-2020, 08:41 PM
    Just to let you know I uploaded a new version of the software to my github. * Teensy 4.1 support with DO7JBH hardware (and a self-built T4.1 to T3.6 adapter) * Menu Assistant by tisho (thanks a lot, tisho!) * more...
    550 replies | 90835 view(s)
  • DD4WH's Avatar
    08-28-2020, 10:44 AM
    for wideband transformers, I have good experience with FT77 ferrite material ring cores and also with binocular cores 73-202. Using this ferrite material leads to better results in the VLF range (however, I have no...
    550 replies | 90835 view(s)
  • DD4WH's Avatar
    08-28-2020, 10:42 AM
    Hi Bill, good to hear your setup works with higher drive strength. I use the default 2mA and it works, but could have to do with shorter wires. You made a very good point in discussing the trade-off between...
    550 replies | 90835 view(s)
  • DD4WH's Avatar
    08-26-2020, 06:58 AM
    Hi! that looks like you have some sophisticated plans, very interesting! Si5351: * maybe you could experiment with the drive strength of the Si5351 which is software controlled?...
    550 replies | 90835 view(s)
  • DD4WH's Avatar
    08-21-2020, 06:10 PM
    Workaround1: * Restart the Codec once you detected twinpeaks Workaround2: * Shift your Sample Buffer by one Sample once detected I use the DAC PCM5102 for my setup You do Not need two Teensy for a transceiver
    12 replies | 336 view(s)
  • DD4WH's Avatar
    08-21-2020, 05:42 PM
    This specific bug made me crazy a few years ago while programming SDR radio software. We termed it "twin peak syndrome", because in an SDR, you have to have a strict 90 degree phase difference in the I & Q input...
    12 replies | 336 view(s)
  • DD4WH's Avatar
    08-19-2020, 03:48 PM
    It seems I had a combined hardware and a software bug that prevented mirror rejection. Now it runs and the mirror rejection seems normal! Excellent. Also, the mirror rejection seems to be highly dependent on the...
    550 replies | 90835 view(s)
  • DD4WH's Avatar
    08-19-2020, 12:15 PM
    DD4WH replied to a thread Bat detector in Audio Projects
    Deleted due to possible misunderstanding
    648 replies | 60347 view(s)
  • DD4WH's Avatar
    08-19-2020, 11:44 AM
    DD4WH replied to a thread Bat detector in Audio Projects
    Yes, exactly. An ultrasound signal ZoomFFT example with real figures: with the original routine in the software, 256 samples are taken as input for the FFT --> 128 real samples as output --> at 192ksps sample...
    648 replies | 60347 view(s)
  • DD4WH's Avatar
    08-18-2020, 07:42 PM
    Regarding the non-existing mirror rejection with the Msi001: * Do you experience also missing mirror rejection? * in your video, Esteban, I can see that there is some mirror rejection on shortwave, but on medium...
    550 replies | 90835 view(s)
  • DD4WH's Avatar
    08-18-2020, 04:41 PM
    @tisho, @Esteban: I have a bugfix for the tuning step / AFC int64_t DeltaF = p.freq - Flo; //Calculate the diference between the "set" and the "result"(without fine correction) frequency DeltaF -=...
    550 replies | 90835 view(s)
  • DD4WH's Avatar
    08-18-2020, 02:30 PM
    0xf380 does not make sense to me at all: 1111001110000000 --> so reg0, no RF synthesizer enabled??? and then, reg0 is written again? 0x6280 --> 110001010000000 and then, which register is written then? 0x0e...
    550 replies | 90835 view(s)
  • DD4WH's Avatar
    08-17-2020, 07:55 AM
    DD4WH replied to a thread Bat detector in Audio Projects
    Ivano, * is there a similar ADC with 500ksps that could be powered on a single 3V3 supply? That would enable users to power them with a single 3V7 lithium 18650 cell. The ADS8685 seems to be using a minimum of 5V...
    648 replies | 60347 view(s)
  • DD4WH's Avatar
    08-16-2020, 01:06 PM
    DD4WH replied to a thread Bat detector in Audio Projects
    Hi Ivano, just a comment on the codec: * the first version of the Bat detector of this thread (four years ago ;-)) had a codec because I had a Teensy audio board at hand and it was easier to handle for me than...
    648 replies | 60347 view(s)
  • DD4WH's Avatar
    08-16-2020, 10:46 AM
    DD4WH replied to a thread Bat detector in Audio Projects
    Hi Edwin, thanks for your correction! That was my fault, I altered my post accordingly! Yes, you are right, depending on the gain of the preamp, you will get a lot of noise anyway and the differences between mics...
    648 replies | 60347 view(s)
  • DD4WH's Avatar
    08-16-2020, 09:51 AM
    DD4WH replied to a thread Bat detector in Audio Projects
    Hi, it is really fantastic to follow the developments by you, Cor & Edwin. This is a superb project! Just my subjective view on the question which microphone to use : * ICS40730 is the best available and tested...
    648 replies | 60347 view(s)
  • DD4WH's Avatar
    08-15-2020, 12:44 PM
    @Esteban, @tisho Thanks again, to you, Esteban and your colleague EA7GIB for your kindness to send me a Msi001 board for integration into the Convolution SDR software! I am working hard to get it working properly and...
    550 replies | 90835 view(s)
  • DD4WH's Avatar
    07-25-2020, 01:15 PM
    Thanks a Lot! Will Take a Look in August, sorry, that its Not possible earlier!
    550 replies | 90835 view(s)
  • DD4WH's Avatar
    07-25-2020, 08:43 AM
    Fantastic developments! I am really impressed! @tisho: the menu looks excellent! I would really like to include it into the main code. Is it possible that you submit a pull request to my github? it would be very...
    550 replies | 90835 view(s)
  • DD4WH's Avatar
    07-23-2020, 12:25 PM
    Bill, exactly, you got it, excellent! Some further comments on the signal flow: * I & Q samples coming in with user-defined sample rate (as an example, lets take 96ksps) * spectrum display (256-point FFT) can...
    550 replies | 90835 view(s)
  • DD4WH's Avatar
    07-22-2020, 11:09 AM
    Excellent! Thanks a lot for trying this and sorry to see it took so much of your time. Thats pretty close to my experience. It took my computer even 50% longer for the computation. However, I did not find a way to...
    550 replies | 90835 view(s)
  • DD4WH's Avatar
    07-22-2020, 10:57 AM
    @WH7U: not sure how the sample & hold in the Tayloe frontend will react exactly. You made a lot of good points there. I am not sure -however- about the causes for your birdies, the cause might be related to missing...
    550 replies | 90835 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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Pitch control of sample playback: current state of things? Today 01:38 PM
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