Final answer:
The mid-band gain of an amplifier is the gain at the center frequency.
Step-by-step explanation:
The mid-band gain of an amplifier is the gain at the midpoint of its frequency response curve, or the gain at the center frequency. It can be calculated by taking the ratio of the output voltage (Vo) to the input voltage (Vsig) at the center frequency. The mid-band gain is a measure of how much the amplifier amplifies the input signal at its center frequency.