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    Generation of 4 Phase Shifted clock Signals

    hello

    How could we generate a phase shifted signal clock signal (90,180, 270) with just basic components?

    Thank you

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    Re: Generation of 4 Phase Shifted clock Signals

    Use an FPGA. Use a microprocessor. Use some resistors, capacitors and inductors.

    Perhaps if you asked a better question you would get a better answer. Like maybe some specifics of exactly what you're trying to do.



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    Re: Generation of 4 Phase Shifted clock Signals

    I need a phase shift of 90°..... to a clock signal of 50% duty cycle which has a frequency of 2.5Mhz by just using the basic components ( transistors, cap, resistors)


    No flips flop,fpga or processor



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    Re: Generation of 4 Phase Shifted clock Signals

    Hi,

    From your first post I thought about sinusoidal waveform with positive and negative voltage swing.

    Now it seems to be a squarewave...
    with unknown voltage swing.
    Unknown risetime and falltime.
    And no other specifications

    Now you need to know that it's technically impossible to generate perfect square wave...thus I find it very important to specify what you want.
    Rs and Cs will modify a square wave .... it will be no longer a square wave.

    ...then you say basic components like: R, C, transistors..
    You can build amplifiers, comparators, opamps, microcontrollers and almost any circuit you like with R, C , transistors...
    Thus I find it important to give detailed restrictions...
    (Rs, Cs, transistors .... is no restriction...)

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    Re: Generation of 4 Phase Shifted clock Signals

    CMOS gate parts can do this easily @ 2.5MHZ look up the CD4000 series - there should be a shift register type part that will do it in 16 or 14 pins ...



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    Re: Generation of 4 Phase Shifted clock Signals

    4-stage chaser (sequencer) made with transistors. It's an extension of a 3-stage chaser whose principle is similar to the classic 2-transistor astable multivibrator. One led at a time is lit, moving from left to right.

    Click image for larger version. 

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    It has more than one mode of operation. If not adjusted carefully it easily starts alternating between two patterns: 0101 and 1010 (creating a 'twin railroad crossing signals' appearance). This tendency is mathematically inherent in sequencers consisting of more than 3 stages. So it's not easy to build a 4-stage chaser.

    This principle works in simulation. With some effort components might be moved, or added, to create a better arrangement. The goal is to make it begin working properly at start-up.



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    Re: Generation of 4 Phase Shifted clock Signals

    apologies for not giving a detailed description.


    description is as follows...( attached image for reference)


    1) I have to use an external clock of 50 % duty cycle with a frequency of 2.5mhz and i should design a circuit which gives me same duty cycle signal but with a phase shift of 90 degrees .


    so now, from the four signals

    signal 3 is just inversion of signal 1

    signal 4 is just inversion of signal 2



    And i could easily do with d flip flop, but i'm kind of interested in just doing the basic components.

    Click image for larger version. 

Name:	IMG_20191016_100804__01.jpg 
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ID:	156071



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    Re: Generation of 4 Phase Shifted clock Signals

    If the frequency is fixed, and you are using logic levels which are precise, you can get 90 degrees shift with one resistor and one capacitor. Just use three inverters, one to invert your original clock to give 180 degrees output and the other two fed in series after the RC delay to give 90 degrees and 270 degrees. However, it will only work if the components and logic levels are stable and the frequency is fixed. You need different RC values for different frequencies and you might have problems maintaining the duty cycle.

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    Re: Generation of 4 Phase Shifted clock Signals

    could we generate a phase shifted signal clock signal (90,180, 270) with just basic components?
    With basic components you will be able to create delays, not properly a phase in the usual sense of this expression in digital electronics. A frequency dependent timming approach should be always avoided, so it is better consider of using logic devices for that.
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    Re: Generation of 4 Phase Shifted clock Signals

    CD4015B should do it (?) 4 stage shift register - dual -

    - - - Updated - - -

    sorry - I missed post #7 - at 2.5MHz it is futile to use discretes because of the delays introduced - 2 x D - flip flops or similar is the engineering way to go ...



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    Re: Generation of 4 Phase Shifted clock Signals

    What kind of system would you have that requires a clock, but doesn't want to use digital logic?



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    Re: Generation of 4 Phase Shifted clock Signals

    Once upon a time, a complex timing waveform generation like the horizontal and vertical TV sync pulses, were designed using only vacuum tubes. But the sync generator was a refrigerator-sized cabinet.
    Then it went to all transistors. But the generator still used a 4U 19 inch rack plus a large external supply.
    Now everything fits in a 2mm X 2mm VLSI running from a pair of AAA batteries.

    The point I'm trying to make is: do you want to build a practical circuit, or do you want to do it the hard way, because of technical curiosity or as an academic exercise?
    There is nothing wrong with the latter, I sometimes like to build such circuits simply to satisfy a technical challenge, to exercise my brain. But those circuits are not practical.


    Now, if what you want is a brain challenge, start with the basic circuit that Brad has suggested. You will find however, that as frequency increases the transistors will require matching and a you'll also means to prevent them to saturate.
    The output waveform will look like crap, so you will require to follow them with a schmitt trigger and a monostable to maintain the duty cycle. You will not able to load the ST output because that will change the operating point. A totem pole buffer will then be required.
    Then as the devices warm up, you may find that the pots require constant tweaking.

    I AM NOT ATTEMPTING TO DISSUADE YOU! QUITE THE CONTRARY, when one builds such circuits, one gains an enormous amount of insight on actual circuit operation. One gains significant admiration for the engineers of yore, which were able to design and build complex systems like computers, Radar, TVs and oscilloscopes with only discrete devices. It is a real eye opening experience.

    OTOH, if you require a practical device, use an IC or two.
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    Re: Generation of 4 Phase Shifted clock Signals

    thank you guys for the response . i figured it out, just using the basic logic gates.



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