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Differences between PLL and DPLL and DLL

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mystique_unbound

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please explain the differences between PLL and DLL and also DPLL
 

gliss

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A PLL is a phase locked loop. It is a circuit that generates an output signal based on the frequency of an input signal. It's usually used for clock multiplication and frequency detection. Say you have a 1Mhz clock and you want to generate a 5Mhz clock that's in sync with the 1Mhz clock.
A DLL is a delay locked loop and all that does is insert a variable delay onto an output signal based from an input signal. You can use it to put two clock lines in sync that have fallen out of sync because of skew for example.
A DPLL is a digital phase locked loop and is just a PLL implemented in an IC instead of discrete analog components. Typically these DPLLs are cheaper, more power efficient and less susceptible to noise compared to discrete PLLs.
 

qslazio

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gliss said:
A PLL is a phase locked loop. It is a circuit that generates an output signal based on the frequency of an input signal. It's usually used for clock multiplication and frequency detection. Say you have a 1Mhz clock and you want to generate a 5Mhz clock that's in sync with the 1Mhz clock.
A DLL is a delay locked loop and all that does is insert a variable delay onto an output signal based from an input signal. You can use it to put two clock lines in sync that have fallen out of sync because of skew for example.
A DPLL is a digital phase locked loop and is just a PLL implemented in an IC instead of discrete analog components. Typically these DPLLs are cheaper, more power efficient and less susceptible to noise compared to discrete PLLs.
so what's the advantage of PLL over DPLL?
 

ahmad_abdulghany

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No advantage of PLL over the DPLL but the DPLL is a newer version from PLL. In old PLLs (after starting to be integrated) all parts of PLL were be integrated except some parts like the VCO, charge pump, ...etc. but now in the new DPLL it's totally integrated even on a single chip.
 

hanjiemy

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Can't be compared together, because of diff. applications.
 

gavin23

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"No advantage of PLL over DPLL ..."? Is this true?

"Can't be compared together, because of diff. applications." Where would I use a PLL and where would I use a DPLL

Thanks,
Gavin
 

leo_o2

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DPLL is usually used for low frequency application. Its accuracy is limited by digital accuracy. PLL/DLL is used for high frequency case.
 

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