Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

this idea will work? (2 PLLs for quadrature generation)

Status
Not open for further replies.

Eugen_E

Full Member level 6
Joined
Nov 29, 2004
Messages
383
Helped
44
Reputation
86
Reaction score
11
Trophy points
1,298
Location
Romania
Activity points
2,862
Hello,

I want to ask if its possible to generate quadrature clock signals using 2 input signals with a small phase shift between them, applied to 2 PLLs like in the image.



I know about obtaining quadrature signals using 2 flip flops and an inverter, but I want to use the above circuit - with PLL, because the maximum frequency of the VCO in the PLL is limited, and I can't aford the frequency division with 2.

Please tell me if this will work, and if the frequency dividers implemented as cascaded flip-flops should be reset at the start, to ensure proper phase shift, or the PLLs wil take care of this?

Thank you.
 

If you are making your own PLL ( IC ) then you can build a quadrature VCO.


Otherwise, you can use a polyphase circuit to generate the quadrature signal without frequency division ( and without need for 2 PLLs )
 

    Eugen_E

    Points: 2
    Helpful Answer Positive Rating
Another method is to generate the signal at 4x the required frequency and then use a 1/4 johnson counter.
 

Status
Not open for further replies.

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top