I have a signal generator at 31.25khz on a buried loop for a toy car to follow. The problem I am having is trying to figure out how to convert this signal to the right pulse 1ms , 1.5 ms and 2ms sqaure wave to an rc servo used to steer the front tires with linkages. There is an inductor mounted on the front of the chassis. That signal only gets weaker and stronger so trying to use a cd4046 pll doesnt seem to work as the signal never goes out of phase so I am stuck on this problem. Is there a way to use this signal and convert it to the proper period to control the rc servo. It is a Hi tech servo and I have the signal amplified and coverted to a saw tooth wave through an opamp. I just need a direction and Googling 'buried wire follower ' are showing results but not servo control only turning on motors left and right to steer. I am novice and just need a direction to think on a solution. Thank you.

 

You have to tackle this project in stages.

The first step is the inductor. The inductor gives out a signal that gets stronger the closer the inductor is to the buried loop wire. However it does not provide information on which way to turn, left or right.

How would you get left or right information?

 

These may be a source of help if modified, the first uses a Picmicro, which if possible, may be the best solution.
http://www.ermicro.com/blog/?p=771
https://www.servomagazine.com/magazine/article/may2015_Predko
Max.