PLL

164

02:27:15

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published 5 years ago

hurz

5 years ago

is it suppose to work, i dont see it does lock. VCO 40kHz divided by 16 would give the 2500Hz reference, but the VCO is running after minutes around 20 and 22kHz which is about half of what it should and this is a problem for PLL with just a simple XOR as phasdetector, what you need in case of such a big tuning range of VCO an additional fequency detector plus a phase detector. BTW is 2500Hz a common reference to something, so is this somehow related to an practical apllication?

hurz

5 years ago

Ahh, and a second order loop filter is also quite novel, better start in this area of knowledge with a first order loop filter.

lucky1811

5 years ago

Congrats for PLL....A lovely circuit for PLL learning

thebugger

5 years ago

Yeah, when I posted it, it worked with a first order filter of 5k/50nF. I made some modifications afterwards. Will return it

thebugger

5 years ago

Also, no I picked 2.5kHz at random, because it corresponds to 40kHz at the given division rate.

hurz

5 years ago

This type of VCO likes to cause CFS

thebugger

5 years ago

CFS?

hurz

5 years ago

After 2 minutes watching the PLL simulation how it does not lock it fails finaly with CFS (Cant Find Solution)

hurz

5 years ago

Buggzy, you are so quiet, i dont want to blame you, just EC cant handel this kind of VCO, as you can see in latest try on PLL from @kiani. You guys just look for a more stable VCO for EC. Nothing personal.

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