Implementing PSK using Atmel Microcontroller ?

Discussion in 'Embedded Systems and Microcontrollers' started by Mjd Kassem, Aug 17, 2017.

  1. Mjd Kassem

    Thread Starter New Member

    Sep 9, 2016
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    Hi every body. I have a question.
    i have uart serial frames every 10 ms i have to check each frame according to some rules and then this frame will be sent as a 50 KHz psk signal
    can i achieve this function using any product of atmel
    i have old design using atmega128 to receive and check each frame and output it vi PISO (shift register) to sine wave generator circuit
     
  2. DickCappels

    Moderator

    Aug 21, 2008
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    Probably not some of the 8051 derivatives or some of the ATTINY parts. Depends on the resources that code requires. A great many AVR controllers, especially ATMEG controllers can probably do it, but it depends on the resources that the code requires.
     
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  3. Mjd Kassem

    Thread Starter New Member

    Sep 9, 2016
    15
    1
    Thank you very much....
    the system i tried to implement is a part of telemetry system, it have to be trusted and robust.
    have i to use the PWM Function to generate carrier (sine wave)?
    can the micro inverse the phase of carrier according to the binary data without overloading or failing?
    what is the new technique belongs to psk implementation ?
    what about vhdl, is it the modern technique design?
    thank you for attention but really i need to design some thing In line with reality..
     
  4. be80be

    AAC Fanatic!

    Jul 5, 2008
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    You can gate the pin your wanting to use.
     
  5. DickCappels

    Moderator

    Aug 21, 2008
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    If my understanding that you already have the necessary PSK functionality running on an ATMEGA128 is correct, then you can be confident of getting the same functionality another AVR controller.

    Is there some reason you cannot use some or all of the ATMEGA128 code that you mentioned?
     
  6. Mjd Kassem

    Thread Starter New Member

    Sep 9, 2016
    15
    1
    sorry for late
    the ATMEGA128 checks each frame which received from it's USART for some rules and then (in case of acceptable frame ) sends this frame to PI-SO shift register to stream the parallel byte in serial vision, this stream of byte goes to analog switch IC which combine the PCM data with carrier signal generated by another circuit
    if you understand my explain you will notice that the ATMEGA128 really don't make real psk modulation and my question
    can we generate a pure 50 KHz PSK signal directly from ATMEGA128 or any another micro controller
     
  7. DickCappels

    Moderator

    Aug 21, 2008
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    Most AVR controllers can make 50 kHz PSK. My reasoning is that the signal being generated is 50 kHz and many AVR controllers can run at 20 MHz, even some ATMEGA controllers. That means the controller can execute nearly 200 instructions per half cycle. That is plenty of cycles to sleep while waiting for an interrupt, during the interrupt change the phase as required by the incoming data, leave the interrupt and prepare for the next half cycle before going back to sleep. There are even enough memory cycles left to do things like look-up values in a sine table if you need an analog output.
     
  8. Mjd Kassem

    Thread Starter New Member

    Sep 9, 2016
    15
    1
    thank you...
    if we need sine wave we have to use the timer in PWM mode, the PWM Frequency is the timer frequency divided by timer top(2^8 or 2^16) so the frequency is limited to some values and the sine wave frequency is equal to PWM frequency divided by time top, this lead to limited sine wave frequency
    this application note describe what i have wrote
    https://www.google.com/url?sa=t&rct...31.pdf&usg=AFQjCNEvL3Gj7I_2BMD6hBX2J6kpRK_4lQ
     
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