I just want to detect when two pulses are completely in sync. I would rather use 555 timers, or even transistors, just because I want the smallest PLL. A digital PLL is ok. I specified a range because the input frequencies can be between 1Hz and 1Khz.
For example, Let's say I have a squarewave signal of 1Hz into one input, and a squarewave signal of 1Khz into another input. I want to create an output that indicates that these signals are not equal.
Also, Let's say I have a squarewave signal of 1Hz into one input, and a squarewave signal of 1Hz into another input. I want to create an output that indicates that these signals are equal.
The output could be as simple as an LED.