need help with a frequency based project

[Wildfox]

Hey everyone,

Im fairly new to electronics so this will probably be simple for most of you, but I would like to build a device as follows using the simplest components available.

The device will take a changing frequency (apx 5v square wave) that will range from 22hz to 2500hz(apx)

I need the device to allow the input signal to pass through unchanged until 2300hz, at 2300hz I need the output to remain at 2300 hz until the input drops back below 2300.

Thanks,
Drew

 

[Roff]

How rapidly can the frequency change?

 

[Wildfox]

How rapidly can the frequency change?

from min to max in the area of a second