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phase shifter circuit

Discussion in 'Electronic Design' started by [email protected], Oct 18, 2007.

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  1. Guest

    anyone know how to design a phase shifter circuit with standard
    components?
    input signal: 6.1v ac rms, 488hz
    phase shift: 23 ±5 deg lead
    output signal: must be capable of driving a DDC DRC-10520 (Ref
    signal).
    ±15V on the board

    any advice/books/links that might aid this design?
     

  2. 488Hz = 2.049180328 ms period time.
    23 degrees is 23/360 x that = 130.9198543 us.
    5 % of that = 6.54992714 us
    So say we are safe with 131 us
    That is 131 cycles of a 1 MHz clock.

    So,
    comparator - 131 cycle delay -
    |
    1MHz
    clock

    Solution: PIC.
    Use 8 pin PIC. 12F629 it has the comparator.
    pins: +, -, in, xtal in, xtal out, out: makes 7.
    One spare pin to break off.

    But actually, if you want to use the DCR-10520 to convert to sine,
    then a PWM on the PIC can do that too.
     
  3. Phil Allison

    Phil Allison Guest

    "Jan Panteltje"

    ** The OP asked for phase " lead " !!!!!!

    Seems he wants to have his info before it arrives.





    ........ Phil
     
  4. My wrong, delay one cycle - lead = 2049.180328 - 130.918542 = 1918.261786
    say 1918 us.
    So delay 1918 clock ticks of 1MHz.
     
  5. Phil Allison

    Phil Allison Guest

    "Jan Panteltje"

    ** That is 337 degrees of lag - according to the OP.

    Betcha.



    ...... Phil
     
  6. Well, we will have to wait and see, I have hopes.
     
  7. Not enough information. You **can** use a simple RC phase shifter with an
    amplitude follower and about four or five stages to give you 337 degrees of
    phase LAG, which is the same thing as 23 degrees of phase LEAD for the
    following cycle.

    Jim

    --
    "If you think you can, or think you can't, you're right."
    --Henry Ford


    anyone know how to design a phase shifter circuit with standard
    components?
    input signal: 6.1v ac rms, 488hz
    phase shift: 23 ±5 deg lead
    output signal: must be capable of driving a DDC DRC-10520 (Ref
    signal).
    ±15V on the board

    any advice/books/links that might aid this design?
     
  8. Phil Hobbs

    Phil Hobbs Guest

    For a fixed frequency, you can get small amounts of phase lead easily
    with an RC highpass network. The phase of such a network is

    tan(23 degrees)
    phi = atan(1/(2*pi*f*RC)), so RC = --------------- = 138 microseconds.
    2*pi*(488 Hz)

    You could use a 140k resistor and a 1nF capacitor. You'll want to use a
    decent cap, so that your phase doesn't vary everyplace, but your spec
    corresponds to about +- 25% capacitor tolerance, so something like a 10%
    film cap will do fine.

    You can clean up the edges with a comparator.

    Cheers,

    Phil Hobbs
     
  9. Tom Bruhns

    Tom Bruhns Guest

    Seems like other posters so far haven't quite groked what a DRC-10520
    is. You need to drive the differential reference input with a
    sinewave (not digital) at 3.4V RMS, and the input impedance is
    guaranteed within 0.5% of 26 kohms. If your input 6.1V is isolated
    (not ground referenced), it should be easy to use series capacitors
    and resistors to scale and phase shift. Phil Hobbs' posting gives
    you the basic info you need for the phase shift part...you just need
    to understand how much attenuation there is in the high pass filter so
    you know the voltage out of it, and then pick the load resistance such
    that the added resistors and the internal DRC-10520 resistance form a
    voltage divider to get you the rest of the way to 3.4 volts.

    If your 6.1V is ground referenced, then I'm unsure whether you will be
    able to use that directly or not. The DRC-10520 data sheet is very
    vague on the common mode range of the reference input, and whether it
    must be driven differentially or if instead RL may be grounded. I'd
    call DDC about that one, to find out. If it can be grounded, then you
    can just use a single series RC from your 6.1V to get the phase shift
    and the attenuation. But DDC's data sheet for this part only shows
    the reference being driven from an isolated transformer winding, so
    it's not really clear how you're supposed to drive it single-ended.
    It's also unclear to me just what they mean by listing different
    single-ended and differential reference input impedances; perhaps you
    can drive it single-ended with RL floating. Again, get ahold of DDC
    and ask them! They should be happy to provide you with some
    applications info about the part. It's to their advantage to have you
    use the part successfully.

    Cheers,
    Tom
     
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