I have 0-12v signal that I want to turn into a 0-30000hz signal. I am looking at the link below as a starting point
http://www.zimbio.com/Broadcast+Har...TC9400+10Hz+10kHz+Voltage+Frequency+Converter

it is 10 to 10k hz which is a decent starting point. My first question is this a good route to take?
Second question, how do I get -5v?

 

There are other sources of V to F IC's - http://www.analog.com/en/analog-to-...s/index.html?gclid=CI3Atar4_qgCFYXc4AodJ3_0Tg

http://www.national.com/mpf/LM/LM331.html#Overview

 

Study the data sheet for the TC4900 part. It shows how to use it with a single ended positive supply. Also note the caveats for the -5v supply if you choose to go that way:

http://ww1.microchip.com/downloads/en/DeviceDoc/21483d.pdf

The data sheet has a few incomplete sentences in it which wouldn't be expected from a company with more than 1 person like Microchip. Also, one of the circuits (I think its fig. 4.3) shows a 0.1 ohm resistor and a 0.2 ohm rheostat as part of the circuit that makes no sense.

 

Attached is the schematic for the board I built. It does give a pulse out. I am struggling with getting the offset to work correctly. The pulse out will stop when Vin is less than 4v. At 4V the FO/2 is 10hz. My understanding from the schematic was I should be able to adjust the OFFSET pot to get the pulse to start at 10hz at around 0.200mv.

I modeled my schematic off this link
http://ecelab.com/circuit-9400-vf-conv-2.jpg

I am using a 5K pot to adjust the Vin.

 

Taking the frequency all the way down to 0Hz may be rather problematic, depending what you want the signal for. In particular, it takes a relatively long time to determine a low frequency, so if you are representing a voltage in this way, the effective bandwidth gets less at low voltages.