Catching 12 khz

Hi everybody.In the picture u can see a cirsuit.This circuit was found to lock from about 139 kHz to 159 KHz.But now i am trying to find 11 to 13 KHz.
I have the formula to find how to calculate for Hz.
'''''''''''''''''''''''''''''''''''''''''''''''''' '''''THE FORMULA''''''''''''''''''''''''''''''''''''''''''' ''''''''''''''''''''''
BW = 1070 sqrt(Vi/foClf) in % of fo. Clf is in μF, Vi in V, and fo in Hz.
'''''''''''''''''''''''''''''''''''''''''''''''''' '''''''''''''''''''''''''''''''''''''''''''''''''' ''''''''''''''''''''''''''''''''''''''''''''''''''
but the problem is i don't know how to do this.I am not an engineer :(
i am only a novice user :)
if any body can send me the right cirsuit i will be really glad.
Thanks for reading my problem.

Where your signal is coming from, what is the amplitude would help to do the calculation.

BUT you can skip the Tone Decoder and use the PIC to do it.
11Khz => freq period = 90.909 uSec
13Khz => freq period = 76.923 uSec

Using PBP Pulsein could give great results.

OR use COUNT wich will return the frequency if you set it to 1Sec count.

That's the easy way, there's a tons of other method using PIC internal Timer/Counter wich will be really much accurate and code efficient...

Novice or not, you might as well learn how to do it - after all we would have to follow the same proceedure...

Start by downloading the DATASHEET for the NE567/SE567. There not only you will find sample application notes but also the way to calculate the Centre Lock Frequency and so determine the values for the appropriate components. Give it a go.

My signal is comming from telephone line.In turkey (if u want)they sent 12 KHz on each kredit finish.For example 1 minute left they sent 12 KHz from the telephone line.I found a shematic for the phone line.When i buy the materials i will try this shematic.

It's so simple to use a NE 567 PLL in 8 pins can ...

Widely distributed overall ...

Alain