timing sensor

Hello

I want to know if there is a component or circuit that can sense a certain frequency of flashing voltage and if the frequency is increased/decreased it makes cetain outputs turn high/low. The frequency would be coming from the output of 555 timer ic.

thank you for reading and any help.

What frequency range?
How much must the frequency change before the output changes state?
What accuracy of frequency shift detection do you need?

A frequency range of about 1 to 100 hz. The frequency must change about 20 hz for out put to chnge state and accuracy of about + or - 5hz

Thank you for your reply

Do you many any 20Hz change, such a 10Hz to 30Hz or 50Hz to 70Hz, etc.?