Need advice on converting high frequency to low frequency

[nicholastok]

Currently I am doing a project on sensor, below is the schematic diagram. From my reading from Fout using the oscilloscope, the nearer an objects/obstacles the frequency increase and vise versa. May I know what I should do/use to convert the high frequency to low frequency and vise versa.

or converting high frequency to low voltage and vise versa.

thanks in advance
Nicholas Tok

 

[Timoh]

Taking a quick glance at the AD 645 block diagram, and by no means am I an expert, it might work if you swap pins 3 and 4.

The block diagram shows an op-amp/voltage comparator on pins 3 and 4, with pin 4 being the positive input. Swapping it to pin 3, which is the negative input, should drive the output of the op-amp in the exact opposite direction than if you had used the positive input.

Or you could put a seperate op-amp in front of the chip and invert the input.

It might work, it might not... It's just an idea.

Tim