Cyclone III - PLL

[Altera_Forum]

Hi, 

 I write for Elsys Design in association with SAFRAN Group.  I am working on a project where I need to get the Cyclone III PLL precision.  I would like to know how much the Cyclone III PLLs are accurate ? What is the uncertanity added to the clock outputs whereas the clock inputs (of 17.734573 MHz) ?  Thanks for your answer.  Antoine MASSON Elsys Design

[Altera_Forum]

There's no freqruency uncertainty. the PLL output frequencies have a rational (m/n) relation to the reference frequency, the exact frequency can be read from the Quartus MegaWizard or the compiler report files. In addition the PLL output has a phase jitter, see the device handbook for the specification.