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Thread: Teensy Convolution SDR (Software Defined Radio)

  1. #201
    Senior Member DD4WH's Avatar
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    Regarding the radio-signal reception of WHF - can it be done so that when this demodulator is turned on, the Sample Rate will set 192k by default? We have to search 192k in the menu for a long time....

    And need to disable the LPF filters when we turn on this demodulator WHF - for bypass.
    I understand that there are not enough controller ports, but you can use, for example, pin3, on which a logical level will appear when the WHF is turned on ....
    But this level should disappear at pin29 above a frequency of 30 MHz.
    Or disable all logic levels at the outputs of the control of LPF above 30 MHz and simple logic on the 5-OR chip, after this frequency, will turn on baypass for WHF.

    And there is an error in the Teensy Convolutio SDR pinout list.
    26pin - LP Filter Band 1 (<320 kHz)
    27pin - LP Filter Band 2 (320.....930 KHz)
    31pin - LP filter Band 3 (930...1975 KHz)
    30pin - LP Filter Band 4 (1975....5375 KHz)
    29pin - LP Filter Band 5 (5375 KHz...37000 KHz)
    Hi Valery,

    1.) sample rate: yes, that is already implemented in the newest version of the software!

    2.) yes, that is also possible, but you would have to alter the function setfreq according to your specific hardware

    3.) Filter pinouts: no, there is no error, it works with my hardware. BUT, you would have to modify the software for your specific hardware/filter layouts [which is not coplicated, just go into "setfreq" and alter the frequencies according to your needs]

    All the best 73s,

    Frank DD4WH

  2. #202
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    Frank, thanks for your reply!
    It is very interesting to me why your compiled file does not work after loading, whereas with the compiled file from Wolfgang DH1AKF everything is fine, the receiver works very well.
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

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  3. #203
    Senior Member+ Frank B's Avatar
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    Frank, i tried RFSIM99 instead (I tried elsie but was not able to use it correctly) - and more important - the exact parts. You can see the parameters if you enter the inductor- partnumber in digikey. You can see the q-factor and resoance frequency, in the digikey result table.
    The result is is a bit different:Click image for larger version. 

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    Only -1.53 db, and the graph looks different. I read RFSim99 is very exact and gives reliable results.

    Any thoughts? Have I done it correctly (I don't have experience with this stuff ??


    The board will have the frontend only, including the filterbank.
    I'm thinking about adding a MMIC amplifier beforethe filters.

  4. #204
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    Frank B, it makes no sense to assemble such complex designs of input filters for a receiver with a mixer of this type.
    Fifth-order low-pass filters are quite enough:
    http://yl2gl.ucoz.net/news/sobiraem_...2019-03-15-146
    You only need to weaken the reception on the odd harmonics - the third and higher....

  5. #205
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    Hi Frank DD4WH

    I would like to make use of your AM_demod header.
    Is it a simple matter of adding the .h .cpp files for compiling and adding the audioconnection code with a switched output path for the AM-demod block?

    Hope you have time to reply, Rob

  6. #206
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    Transceiver

    Frank

    Have you, or has anyone you know of, made a transceiver version of this project?

    Joe
    W3JDR

  7. #207
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    Hi Frank. Teensy SDR will be supported also by new Teensy 4.0 ? Thanks

  8. #208
    Senior Member DD4WH's Avatar
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    Quote Originally Posted by robjohn View Post
    I would like to make use of your AM_demod header.
    Is it a simple matter of adding the .h .cpp files for compiling and adding the audioconnection code with a switched output path for the AM-demod block?
    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!

    The Convolution SDR uses 32-bit floating point processing outside of the audio lib and it does not make use of audio-lib-like processing blocks.

    Hope that helps!

    Regards,

    Frank DD4WH

  9. #209
    Senior Member DD4WH's Avatar
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    Quote Originally Posted by joedarock View Post
    Have you, or has anyone you know of, made a transceiver version of this project?
    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 STM32F7). This implements a full featured ham radio transceiver.

    https://github.com/df8oe/UHSDR/wiki

    All the best,

    Frank DD4WH

  10. #210
    Senior Member DD4WH's Avatar
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    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 home :-).

    You would have to:

    * rebuild your hardware, because the audio board has to use different pins
    * think about I2C expanders, because probably the T4 does not have enough output pins to do all the external switching (bandpass filters etc.)
    * install the newest Teensyduino and other libs
    * reinstall the newer CMSIS DSP library --> I am not sure if anybody got this to work with the T4

    So, as you can see, its a lot of work and a lot of fiddling around.

    If you are willing to try and do that, go ahead! I would be happy to hear about progress in using the T4 with the Teensy Convolution SDR code!

    All the best,

    Frank DD4WH

  11. #211
    Senior Member DD4WH's Avatar
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    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 little more.

    However, I will be travelling the next four weeks, so not much time for that . . .

    All the best,

    Frank DD4WH

  12. #212
    Senior Member DD4WH's Avatar
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    Quote Originally Posted by yl2gl View Post
    It is very interesting to me why your compiled file does not work after loading, whereas with the compiled file from Wolfgang DH1AKF everything is fine, the receiver works very well.
    Hi Valeri,

    well thats explainable:

    * there are different options to use the oscillator chip Si5351: which clock output do you use? [CLK0, CLK1, CLK2] and which Xtal frequency did you install? [25MHz, 27MHz]

    These six different options alone explain why a specifically compiled file works on your machine and the other does not.

    That is exactly the reason why I would recommend to compile the ino. - file by yourself according to your needs! It is not so complicated as you might think [especially for a trained ham radio amateur ;-)]!

    All the best,

    Frank DD4WH

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