Digital phase shifter

Discussion in 'General Electronics Chat' started by DominusDRR, Sep 3, 2009.

  1. DominusDRR

    Thread Starter Member

    May 25, 2009
    26
    0
    Hello.

    Are there a way to make a digital phase shifter with flips flops and logic gates?

    Thank you.
     
  2. mik3

    Senior Member

    Feb 4, 2008
    4,846
    63
    A simple phase shifter can be made with a NOT gate due to its propagation delay. The more gates you add in series the more the phase shift.
     
  3. DominusDRR

    Thread Starter Member

    May 25, 2009
    26
    0
    Please. Do you have a circuit that can share?
     
  4. mik3

    Senior Member

    Feb 4, 2008
    4,846
    63
    Connect two NOT gates in series (the output of the first in the input of the second). Then connect you signal on the input of the first. You will get a delay of about 50ns to see the signal on the output of the second gate.
     
  5. DominusDRR

    Thread Starter Member

    May 25, 2009
    26
    0
    Thanks But I need phase shifted (90º, 180º, 270º) etc
     
  6. mik3

    Senior Member

    Feb 4, 2008
    4,846
    63
    180 is easily implemented with a NOT gate. To achieve other phase shifts with a delay you have to know the signal's frequency and calculate the appropriate delay otherwise you need more complex circuits which read the signal and perform the required delay.
     
  7. DominusDRR

    Thread Starter Member

    May 25, 2009
    26
    0
    But if the signal is PWM and high frequency? (100MHz)
     
  8. mik3

    Senior Member

    Feb 4, 2008
    4,846
    63
    First why do you need such a high frequency PWM signal?

    How you generate it?
     
  9. DominusDRR

    Thread Starter Member

    May 25, 2009
    26
    0
    PWM signal comes from the comparison of a signal 1MHZ with a triangular signal of 100MHz
     
  10. mik3

    Senior Member

    Feb 4, 2008
    4,846
    63
    And you want to phase shift one signal as to vary the duty cycle?

    But why you need such high frequencies?
     
  11. DominusDRR

    Thread Starter Member

    May 25, 2009
    26
    0
    Yes. I want to phase shift the duty cycle in 90 ° and add the two signals (input and output) to increase the duty cycle time.
     
  12. mik3

    Senior Member

    Feb 4, 2008
    4,846
    63
    Why don't you use a triangular wave, a comparator and a pot to generate PWM from 0% to 100%.

    Feed the triangular wave on one input of the comparator and the output voltage of the pot to the other.
     
  13. DominusDRR

    Thread Starter Member

    May 25, 2009
    26
    0
  14. DominusDRR

    Thread Starter Member

    May 25, 2009
    26
    0
Loading...