Phase difference detector, 433.92MHz

Discussion in 'Wireless & RF Design' started by AndyPLL, May 3, 2006.

  1. AndyPLL

    Thread Starter New Member

    May 3, 2006
    3
    0
    Hi, I am hoping to detect the phase difference from a 433.92MHz carrier signal detected at two antennas, where one antenna is about a 1/4 wavelength further from the transmitter than the other.

    The circuit looks as follows. I use PLLs to ensure phase lock on the carrier and pass the 2 signals to a phase detector:

    Code ( (Unknown Language)):
    1.  
    2. (Antenna 1)              (Antenna 2)
    3. |                      |
    4. (JFET AMP 1)              (JFET AMP 2)
    5. |                      |
    6. (~433.92 MHz Bandpass 1)    (~433.92 MHz Bandpass 2)
    7. |                      |
    8. (BJT AMP 1)              (BJT AMP 2)
    9. |                      |
    10. (PLL1)                  (PLL2)
    11. |                      |
    12. |                      |
    13. (PHASE COMP) -------------------------------|                          
    14. |
    15. |
    16. OUTPUT
    17.  
    I hope you can understand my circuit diagram. A second Bandpass filter after the BJT Amps would double the 6dB of the first to 12dB, so I will probably put those in each line aswell.

    My questions are:

    1) Do I really need the PLLs? Can I just put the antenna signals into the Phase difference detector without phase lock, or do I really need the VCO (powered) output?
    2) If PLLs needed, what ICs do you recommend? Do I need special PLLs capable of locking onto a 433.92MHz signal? Or can I somehow use standard 4046/LM565??
    3) What IC for final phase comparator? Anything special required?

    I hope you can answer my questions!! If you can, then you have probably guessed that the circuit is designed to detect which antenna is closest to the transmitter source, within a wavelength as per diagram:

    Code ( (Unknown Language)):
    1.  
    2. Antenna1
    3.  
    4.     -------------------------------//------------------------- Transmitter
    5.  
    6.     Antenna2
    7.  
    Antennae are about a foot apart, transmitter is off in the distance.

    HOPE YOU CAN HELP!!!!!
     
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