Frequency Multiplier for variable input pulses

[ridgemao1983]

I don't think a PLL will work for variable input frequency, because it needs the locking time. My input frequency is between 0Hz to 1MHz.

But someone has did it, so I just want to know how they did it. Did they count the previous interval of the input pulse and generate the new frequency?

How did they achieve this accurate frequency multiplier:
"Unit to multiply the input impulses with a proportional factor F1 and a reciprocal factor F2, both adjustable in a range of 0.005 to 9.9999"

**broken link removed**

 

[ridgemao1983]

Now I know it is called "digital pll", and I found it difficult to design, you need all of those algorithms.

Does anyone has some simple ways to implement a digital pll?