How to determine the uncertinity of this circuit

[lonkenzo]

Hi,
This is a circuit which count the frequency of a signal and display it with 7 Segments LEDs.

I want to study and realize it but I don't know how to obtain the uncertinity of the results.

 

[shaiko]

The device on the left is a PIC microcontroller.
It's the "brain" behind the application.

In general, it counts the clock transitions of the signal at question and compares them to it's own system clock which is generated by the 13MHz oscilator that connects to the XTAL pins at the bottom of the device schematic.

It gets a result and then drives the 7 segments LEDs to show the result of the comparation.

 

[sky_123]

What Shaiko said, and also btw the device on the right is a PLL chip, and only the prescaler portion of it is being used.
It was described in another thread that I noticed a while back : https://www.edaboard.com/threads/54108/

However, that i.c. is quite hard to find now. I'm planning to do something similar, but plan to use a different device,
a dedicated prescaler: MC12080
Someone already did this: **broken link removed**