Passive Phase lock loop

[anum_pirkani]

Hi..

I am looking for a PASSIVE PLL component that I can use after VCO followed by 2 way power divider in my design.

I have searched for PLL but i have found active ones...!!!

Frequency is approximately 900MHz

VCO------PASSIVE PLL-----2-WAY POWER DIVIDER


Regards

 

[crutschow]

Why do you think there is such a thing as a passive PLL? What frequency are you trying to lock to what other frequency with this PLL?

 

[chuckey]

If your two RF sources are in phase at some physical point, add a 1/4 wave length coax line in series with one, then use a resistive adder. At this point a detector will give you a signal that goes +ve/-ve as the phases change. The problem is that it cannot detect the direction of the phase change, so you need a "non ambigous" detector to get your phasing into the correct quadrant, this is basically the same as above but the added line is a extra 1/4 wavelength and the detector just gives a gives a positive output when the RF is phased up correctly and no output when its trying to anti phase the RFs. When its doing this just fire a monostable to inject a small voltage into the circuit to bring the VCO back into the right quadrant. As used in the PYE VHF TV transmitters, 1955 -1984.
Frank