Which aircraft fuel quantity indicating system incorporates a signal amplifier?

The electronic fuel quantity indicating system is the correct choice because it utilizes a signal amplifier as part of its operational process. In this system, sensors measure fuel levels and convert these measurements into electrical signals, which are typically very low in amplitude. The signal amplifier is crucial as it enhances these low-level signals to levels that can be effectively processed and displayed on the cockpit instruments. This technology allows for more accurate and responsive readings of fuel quantity, which is essential for flight safety and efficient fuel management.

Other systems, such as mechanical, capacitance-type, or optical, operate on different principles and do not require a signal amplifier for their functionality. Mechanical systems rely on physical displacement of a float or similar mechanism to indicate fuel quantity, while capacitance-type systems measure changes in electrical capacitance as fuel levels vary, and optical systems use light to measure the fuel level. Each of these methods has its own advantages and limitations, but none incorporate a signal amplifier in the same way that electronic systems do.