433MHz PLL

Thread Starter

AndyPLL

Joined May 3, 2006
3
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 in quote. I use PLLs to ensure phase lock on the carrier and pass the 2 signals to a phase detector:

(Antenna 1) (Antenna 2)
| |
(JFET AMP 1) (JFET AMP 2)
| |
(~433.92 MHz Bandpass 1) (~433.92 MHz Bandpass 2)
| |
(BJT AMP 1) (BJT AMP 2)-
| |
(PLL1) (PLL2)
| |
|-----------------------------------------|
|
|
(PHASE COMP )
|
|
OUTPUT

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 in quote:

Antenna1
.
. ---- ------------------------------------------------------ Transmitter
.
Antenna2

Antennae are about a foot apart.

HOPE YOU CAN HELP!!!!!



 

Grant

Joined Mar 5, 2006
17
Originally posted by AndyPLL@May 11 2006, 03:44 PM
thanks for the help!

http://actgeoeng.mod.net.au
[post=16997]Quoted post[/post]​
Aw..come on Andy, don't be like that! We thought RadioRon's advice to you was quite helpful- you are not the only one who uses another forum!
Cheers,
Grant
 
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