Small Signal Envelope Bandwidth from DC to 30 MHz

I am reading the data sheet of AD8302. The data sheet says Small Signal Envelope Bandwidth from DC to 30 MHz.
Could anyone please tell me what is the meaning of the term "Small Signal Envelope Bandwidth".

it means if there is a sudden relatively small change in input power level, the detected output will be mostly settled out in 100 nanoseconds

It is the bandwidth of the video output (baseband) demodulated signal, without using C2 video filtering capacitor (and C8 respectively for phase output).