can I hire somebody here?

[joe_rocket]

I thought hysteresis on one meant one would have a "lag" and therefore produce a different voltage if the rate was increased too fast

 

[mbarazeen]

both will reflect the frequency very fast, so its not propper way to find rate of change of freq. what you think in your mind is done easily by the differentiator, instead of 374 you still can use another OP-07, the dual voltage op-amp as a non inverting amplifier and as a differentiator for the next two steps before feeding it to the comparator. dont forget the out put of F-V conv is a negetive voltage and when you feed the differentiator its again inverted. ie for +ve change of rate of freq above the set limit you will get the trigger.