Which of the following modulated signal has the best noise tolerance?

Options

A. Long-wave
B. Short-wav
C. Medium-wave
D. Amplitude-modulated

Answer

To determine which modulated signal has the best noise tolerance among long wave, short wave, medium wave, and amplitude modulated signals, we need to understand the concept of noise tolerance and how different types of waves respond to noise.

### Step-by-Step Solution:

1. **Define Noise Tolerance**:
- Noise tolerance refers to the ability of a signal to withstand interference from unwanted signals (noise) during transmission. A signal with high noise tolerance can maintain its integrity better in the presence of noise.

2. **Identify the Types of Waves**:
- The question lists four types of waves: long wave, short wave, medium wave, and amplitude modulated (AM) signals. It's important to understand how each type behaves in terms of noise.

3. **Compare Noise Tolerance of Different Waves**:
- **Short Wave**: Generally has a higher frequency and can travel longer distances with better clarity. It is less susceptible to noise compared to the other types.
- **Medium Wave**: Has moderate noise tolerance, better than long wave but not as good as short wave.
- **Long Wave**: Typically has the lowest frequency and is more prone to noise interference, making it less effective in noisy environments.
- **Amplitude Modulated (AM)**: This refers to a modulation technique rather than a specific frequency band. AM signals can be affected by noise, especially in lower frequency bands.

4. **Conclusion**:
- Based on the comparison, short wave signals exhibit the best noise tolerance, followed by medium wave, and then long wave. Therefore, the answer to the question is **short wave**.

### Final Answer:
**Short wave has the best noise tolerance among the given options.**

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