2 x square wave oscillators - unwanted modulation

Discussion in 'Digital Circuit Design' started by Tony Elliott, Jul 10, 2016.

  1. Tony Elliott

    Thread Starter Member

    May 8, 2015
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    Hi All-out circuits,

    I am using two square wave oscillators, when i put the outputs together they modulate. you can see the schematic attached. I don't want this modulation. Is there a way of fixing this, maybe an idea to use a diode on each output?
     
  2. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    IC1 is the 555 oscillator.
    IC2A is a divide by 2 circuit.
    What do you mean with modulate ?

    Bertus
     
  3. Tony Elliott

    Thread Starter Member

    May 8, 2015
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    Both square waves connect as one modulating pattern. it sounds great but I would like to have two separate square waves on the oscilloscope and speakers.
     
  4. bertus

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  5. Tony Elliott

    Thread Starter Member

    May 8, 2015
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    Here is some footage of me playing with the modulation.
    The schematic itself is not mine so I just followed the design.
     
  6. benta

    Member

    Dec 7, 2015
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    Why are you connecting the outputs?
     
    Last edited: Jul 10, 2016
  7. BobTPH

    Active Member

    Jun 5, 2013
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    It might help if you clued us in as to how the two signals are combined.

    Bob
     
  8. GopherT

    AAC Fanatic!

    Nov 23, 2012
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    Please show the rest of the schematic datasheet (source of your attachment in post 1).
     
  9. Tony Elliott

    Thread Starter Member

    May 8, 2015
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    I have two circuits and connect x2-2 on the first to the second circuit and connect the x2-1 on the first circuit to the second circuit
     
  10. Tony Elliott

    Thread Starter Member

    May 8, 2015
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    I was emailed this data sheet so sorry i don't have a source
     
  11. GopherT

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    Use the Upload file button as you make a post and attach the datasheet. PDF files and most image files are acceptable.
     
  12. Tony Elliott

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    May 8, 2015
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    squarewave.jpg
     
  13. GopherT

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  14. bertus

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    Apr 5, 2008
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    Hello,

    Your 555 circuit is producing needle pulses, as there is no resistor in the discharge line.
    See the following drawing for more info:

    555_circuit_mainly_high_signal.png

    Bertus
     
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  15. Alec_t

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    Sep 17, 2013
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    :confused: There are 4 connection points. You mention only 2.
     
  16. Tony Elliott

    Thread Starter Member

    May 8, 2015
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    the first two connections are the battery inputs,
     
  17. Tony Elliott

    Thread Starter Member

    May 8, 2015
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    this looks interesting, I will experiment with this, I could even make pulse with stretcher.
     
  18. BobTPH

    Active Member

    Jun 5, 2013
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    So one square wave oscillator is supplying power to a second square wave oscillator. What do you expect the result to be?

    Bob
     
  19. Tony Elliott

    Thread Starter Member

    May 8, 2015
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    No there are two of these circuits, and when both outputs are connected in a passive mixer I get two modulating square waves.
     
  20. bertus

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