In the precision circuit, an operational amplifier provides a buffered output and also acts as a 2-pole filter. The ripple will beless than 5 mV peak for all frequencies above 1 kHz, and the response time will be much quicker than in Part 1. However, for input frequencies below 200 Hz, this circuit will have worse ripple than the figure. The engineering of the filter time-constants to get adequate response and small enough ripple simply requires a study of the compromises to be made.
Inherently, V-to-F converter response can be fast, but F-to-V response cannot.