A longer pulse has a _____ Q factor.

A longer pulse has a _____ Q factor.

• A. Lower
• B. Directly
• C. Higher
• D. Inversely

Answer: (C)

Quality factor measures how selectively a system responds at its resonant frequency, essentially comparing how much energy it stores to how much it loses per cycle. It’s commonly expressed as Q = f0 / Δf, where Δf is the bandwidth. A longer pulse in time means the signal lasts longer and its frequency content is more tightly centered around the main frequency, so the bandwidth Δf is smaller. With a smaller Δf, the ratio f0/Δf increases, giving a higher Q factor. In short, longer pulses are more frequency-selective, which corresponds to a higher Q. Shorter pulses spread energy over a wider range of frequencies, producing a lower Q.

Quality factor measures how selectively a system responds at its resonant frequency, essentially comparing how much energy it stores to how much it loses per cycle. It’s commonly expressed as Q = f0 / Δf, where Δf is the bandwidth. A longer pulse in time means the signal lasts longer and its frequency content is more tightly centered around the main frequency, so the bandwidth Δf is smaller. With a smaller Δf, the ratio f0/Δf increases, giving a higher Q factor. In short, longer pulses are more frequency-selective, which corresponds to a higher Q. Shorter pulses spread energy over a wider range of frequencies, producing a lower Q.