PI controller

Thread Starter


Joined Oct 30, 2020
Hello. No, this is from the book "Phase-Locked Loops: Design, Simulation, and Applications" by Ronald E. Best.


Joined Jun 17, 2014
Hello. Could you help me? How was the expression for T1 obtained? Thanks.View attachment 256031

I took a quick look and it looks like there could be a problem with that T1 formula. Looks like a sqrt(10) factor may be missing or included where it shouldnt be. You'll have to go through it in detail i guess.

So it may be a book error. I have been finding technical book errors since i was in something like 7th grade. This one could be such also but the only way to know is to go through the entire derivation.
I found one on the web (God forbid) that was very very complicated and it was obvious something was wrong. The derivation was very complicated though and took a couple hours to deduce from basic principles.
It can be very annoying. One of the explanations i got back in the 1980's was that very often non technical people are responsible for the type and dont realize when they typed something wrong or backwards. The original formulation might have been perfect, but after the 'translation' it becomes mangled and unusable.
I've even found very advanced texts to be wrong now and then. Sometimes easy to prove, sometimes harder.

The best books show the derivation so you can go through it step by step and follow their logic, so if they made a typo you can find it much easier. Unfortunately they dont always do that. You may have to contact the publisher.