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Triangular signal shift phase

Discussion in 'General Electronics Discussion' started by belhouss13, Jan 27, 2016.

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  1. belhouss13


    Jan 27, 2016
    hello, firsly sorry if i made error in english i still improve my langage.

    my problematic is simple.
    I have one triangular signal with frequency of 3.6 KHz, and 5Vpp. This signal is use on the analogic field (not numeric application). I need to have this signal in phase with an others fixed signal. Do it exist simple analogique solution to make a triangular signal phase shift systeme with controllable dephasage?
  2. duke37


    Jan 9, 2011
    Bon jour belhouss13.

    I presume you want a triangular signal with a frequency of 3.6kHz locked to another signal.
    Note K is degrees Kelvin. Upper and lower case letters are critical in electronics.

    You say you have triangular signal already, please tell us how this is produced.
    If you wish to have the signal locked to a reference, then the way I would do it would be to square up the reference and then pass it through an integrator. This could be as simple as a resistor and capacitor or something more complicated depending on the accuracy that you desire.

    Your english is better than my french.:)
  3. Merlin3189


    Aug 4, 2011
    Quite agree with your comment about K and k, then I was slightly thrown by "square up".
    I had been thinking of either a Schmidt trigger with varying DC bias so that it triggered at different points along the slope of the triangle wave, or to use the input wave to trigger a monostable ( < about 200 microsec pulse), to give a new series of pulses at the same frequency, but with different transitions. Then pass the resulting non 50:50 square wave through an integrator to get a new triangle wave. But the trouble is, because neither gives an equal mark:space ratio square wave, the integrated wave is an asymmetric triangle.
    When I read "square" I immediately thought you were squaring the triangle wave to double the frequency, so that after adding the phase shift, you could divide by 2 to restore the 50:50 ratio square wave, which could integrate to give an accurate triangle.

    Not a criticism, just noting that it's not just upper & lower case that can cause confusion! Once my brain took in the "up" as well, I realised my error. And when writing my bit above, I struggled to think how I should describe a square wave when it is not square but elongated, oblong, rectangular, ...? These things crop up all over. Only yesterday I was struggling to help someone with a calculation where he had used m and n as the symbols for his distances. So when I wanted to say 3 times m metres, I was writing 3mm, which I eventually decided should be 3m m.
  4. AnalogKid


    Jun 10, 2015
    What you are describing is a variation of a phase-locked loop. There are two basically different ways to do this. One is to recreate the input signal at a different phase; that is what is discussed in posts #2 and #3. A potential problem is that a circuit based on a square wave and integrator has the signal frequency and amplitude inherently locked together. Getting both to track the input input waveform exactly is doable, but not simple.

    The other way is to shift the phase of the actual input signal using some kind of group delay mechanism. Back in another life I designed and built a voltage-variable delay line for broadcast-quality video. A true analog phase delay is possible, but 3.6 kHz is a very low frequency for such circuits. Another approach is to digitize the input triangle wave with an A/D converter, write it to a memory, and recreate it from the memory with a D/A converter. All of this can be done within a medium-speed microcontroller such as a PIC, but it also can be done without any microcontroller or device programing. One A/D, one D/A, one memory chip, two binary counters, one clock source, and a monostable that is controlled by whatever it is that is controlling the phase delay.

  5. belhouss13


    Jan 27, 2016
    Hello Duke37, Merlin3189 and analogkid,

    thank you for your response and Duke37 I note your comment it is true, I need to be accurate and rigorous.
    In fact, I don't have more information concerning this signal, it comes from a black box with an output. I need to make a system which can provide a controllable dephasage because the debugger should be controlled by an operator. I'm sorry for this ambiguous description of the problem, but I don't have more input.
    I derived my signal pass it through tow monostable the first control the dephasage and the second rebuilt the signal and after, I integrate the signal to refund my triangular signal to finish an adaptation of the offset. Then thank you very much for your help.

    The idea of digitized the signal is a very good idea, but it seems to be more difficult than the analogue solution: for my application the first basic solution seems to be ok: I'm sure that I could use it in another application :)

    in any case thank so much for the help
  6. dorke


    Jun 20, 2015
    If I understand correctly what you did.
    It is only possible if the input triangular signal is a fixed one.
    that is frequency and offset are fixed and known.

    Is this the case?
  7. belhouss13


    Jan 27, 2016
    Hello Dorke,

    yes it is. the frequency and the offset are fixed.

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