How to double(quadruple) frequency which is no 50%duty cycle

[twlin1]

If there is a waveform which is not 50% duty cycle, like 20%(80%), how to generate its double or quadruple frequency with the same duty cycle?

Thanks in advance.

 

[rowokii]

Re: How to double(quadruple) frequency which is no 50%duty c

How about this:

1. From picture below signal A is the original clock wave form.
2. Use DLL with a center tap to lock on to rising edges of signal A to create signal B.
3. AND signal A & B to create signal C.
4. Use a second center tap DLL to lock on the rising to fall edges of signal C to make signal D. You need this since even though the picture looks like 50% duty cycle, this won't be the case in general.
4. AND signal C & _D_ (inverted D) to generate signal E.

You can extend the concept to make 4x clock.

 

[twlin1]

Re: How to double(quadruple) frequency which is no 50%duty c

Thanks. It helps much!