Interpreting the circuit diagram in the dataasheet of TGS2442
You need to drive the two transistors with separate control signals. 

The PDF at this link is somewhat easier to read.  

You can zoom in on the timing diagram in that PDF  - in the one you linked to the zoom doesn't seem to work and you (or at least I) can't download the PDF.

The heat pulse begins where the measure pulse ends.  

I don't see any reasonable way to drive both with a single signal.  

You have a period where one is on followed by a period where the other is on followed by a period where neither is on.  I don't see getting that out of one signal without having some extra circuitry, so just use two digital outputs from your controller and save yourself some hassle.

The cycle looks like this:


Activate Vc
Wait 2.5 msec
Read output value
Wait 2.5 msec
Turn off Vc
Turn on Vh
Wait 14 ms
Turn off Vh
Wait 981 msec
Repeat from step 1.