Absolutely right Melanie,
Dwayne use Transisor, op amp, voltage comparator will not resolve the problem. But in this case what i think... never test but...

do 2 Pulsin reading one for state 1 and 1 for state 0 will give you the entire period.

Pulsin SignalInput,1,TimeHigh
Pulsin SignalInput,0,TimeLow
EntirePeriod=TimeHigh+TimeLow

Results may vary a few depending the speed of intruction execution or triger detection. Why not read a few time (5-10 times) EntirePeriod and do the average of them. Send results to an LCD to see what it gives to you. try to vary the input amplitude too and see how different they are.

Of course you can do the same job with two LM567. But as you request less component as possible. But for time consuming ...

keep us inform

regards