Create a shift on a square signal

Discussion in 'General Electronics Chat' started by kanoun, Apr 14, 2015.

  1. kanoun

    Thread Starter Member

    Jan 29, 2015
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    Hi guys,

    I need to create a 3 signals that are shifted from a reference one (see attached) S1 is the reference one, H is the clock. I'm trying to use a shift regester. My understing is that I need a in serie out series shift register. Is that true? anyway could you advise how to do so.
    I'm really not an expert in electronics.
    Many thanks for your help
     
  2. dl324

    Distinguished Member

    Mar 30, 2015
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    Hi Kanoun,

    How is S1 being generated? Are there any constraints on how S2, S3, and S4 are generated?

    Is this a home work problem?
     
  3. kanoun

    Thread Starter Member

    Jan 29, 2015
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    S1 is generated with ne555
     
  4. dl324

    Distinguished Member

    Mar 30, 2015
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    Is using a couple of flip flops and 4 AND gates acceptable?

    Is the last waveform drawn correctly? Seems like it should be HI for the first half cycle of H.
     
  5. crutschow

    Expert

    Mar 14, 2008
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    Yes, you can use a serial-in shift register with parallel out.
    As Dennis asked, is this a homework problem?
     
  6. kanoun

    Thread Starter Member

    Jan 29, 2015
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    Many thanks guys ... Could you recommend how we connect cause I'm stuck with the one I have :(
     
  7. kanoun

    Thread Starter Member

    Jan 29, 2015
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  8. kanoun

    Thread Starter Member

    Jan 29, 2015
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    I did a mistake with the last one you're right.no it is not a homework ... I'm too old for homework :)
     
  9. dl324

    Distinguished Member

    Mar 30, 2015
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    Hi kanoun,

    You're device will work. Could also use half of a CD4015 or a CD4013 plus CD4011 (which I think is more interesting).
     
  10. kanoun

    Thread Starter Member

    Jan 29, 2015
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    Could you help with how to connect please
     
  11. ScottWang

    Moderator

    Aug 23, 2012
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    1. What is the circuit uesed for?
    2. The S2 is going high when the S1 is at the falling edge.

    Assuming that there are S3 and S4 below the S2:
    3. S3 is going high when S2 is at the falling edge
    4. S4 is going high when S3 is at the falling edge

    S1 output is repeating:
    5. S1 is going high when S4 is at the falling edge.

    So, does what you want is a johnson counter?

    johnson counter d flip flop.
     
  12. crutschow

    Expert

    Mar 14, 2008
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    If you want to use the SN74HC595, then connect the RCLK and SCLK together to the H signal.
    Connect S1 signal to the SER input.
    Outputs QA, QB, and QC should have the signals you want.
     
    kanoun likes this.
  13. ErnieM

    AAC Fanatic!

    Apr 24, 2011
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    I do not see where the "H" signal is being generated.

    kanoun?
     
  14. dl324

    Distinguished Member

    Mar 30, 2015
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    It's equally unclear how S1 is being generated (aside from 555 timer without a schematic) and how it's waveform is being synch'ed to H. If the HI/LO times aren't controlled sufficiently, using a shift register might not give the desired results.

    Much simpler to use a couple flip flops and a pack of AND gates.
     
  15. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    There is a discrepance in your drawing.
    You are stating 50 seconds for a cycle, I come to 40 seconds:
    crenaux_remark.jpg

    When you have the "H" signal, use it to clock a 4017 and reset it at the wanted number of pulses.

    Bertus
     
  16. kanoun

    Thread Starter Member

    Jan 29, 2015
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    Yes yo
    yes you're right ... It is a mistake when I drowed the signals :) ... Anyway Ill use the 4017 I finally understood how it's work ...
     
  17. AnalogKid

    Distinguished Member

    Aug 1, 2013
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    OR, what about a CD4017? Tie output 4 to the Reset input.

    ak
     
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