Ratio detector characteristics: Which of the following statements about a ratio detector is correct?

Introduction / Context:
The ratio detector is a frequency demodulator used in FM receivers. It is derived from the phase discriminator but has important advantages in terms of automatic amplitude limiting.

Given Data / Assumptions:

• Ratio detector is used in FM demodulation.
• Operates without a limiter stage in some designs.

Concept / Approach:

A ratio detector generates an output voltage proportional to the frequency deviation of the input FM signal. Unlike the phase discriminator, it inherently cancels amplitude variations, providing stabilization against signal strength fluctuations.

Step-by-Step Solution:

Verification / Alternative check:

Radio receiver design manuals confirm ratio detectors improve performance by rejecting AM noise and signal strength changes.

Why Other Options Are Wrong:

• (a) Linearity is not worse; it is acceptable.
• (b) Output is not exactly double; misleading.
• (d) Diode reversal alone is not the defining feature.
• (e) Output is not constant—it varies with frequency deviation.

Common Pitfalls:

• Assuming ratio detector improves linearity—it actually improves amplitude stability.

Final Answer:

Stabilization against signal strength variations is provided