Statement: The noise figure of a multi-cavity klystron amplifier is very low. Choose the correct truth value.

Introduction:
Noise figure (NF) describes how much an amplifier degrades the signal-to-noise ratio. Understanding typical NF values for vacuum-electronic RF power devices such as klystrons is important in receiver front-end design and link budgets.

Given Data / Assumptions:

• Device: multi-cavity klystron amplifier
• Operating region: RF/microwave power amplification
• Comparison: low-noise front-end devices vs high-power devices

Concept / Approach:
Klystron amplifiers are primarily power devices with high gain and efficiency for transmit chains. They are not used as low-noise front ends; their noise figures are comparatively high (often many dB above specialized LNAs). Thus the statement claiming “very low” NF is incorrect.

Step-by-Step Discussion:

Verification / Alternative check:
Transmitter line-ups place klystrons after the exciter; receivers avoid klystrons in the first stage precisely due to noise.

Why Other Options Are Wrong:

• True: contradicts common usage and measured NF performance of klystron power amplifiers.

Common Pitfalls:
Confusing high gain/efficiency with low noise; assuming all vacuum devices have inherently low noise.

Final Answer:
False