Identify the incorrect statement from the following

Options

A. AM detection is carried out using a rectifier and an envelope detector.
B. Pulse position denotes the time of rise or fall of the pulse amplitude.
C. Modulation index `mu` is kept `ge` 1, to avoid distoriton.
D. Facsimile (FAX) scans the contents of the document to create electronic signals.

Explanation

To identify the incorrect statement regarding AM detection, let's analyze each of the provided statements step by step.

### Step-by-Step Solution:

1. **Statement 1: AM detection is carried out using a rectifier and an envelope detector.**
- **Analysis:** This statement is true. AM detection indeed involves the use of a rectifier to demodulate the amplitude-modulated signal and an envelope detector to extract the original message signal from the modulated carrier wave.

2. **Statement 2: Pulse position denotes the time of rise or fall of a pulse amplitude.**
- **Analysis:** This statement is also true. In pulse position modulation (PPM), the position of the pulse in time indicates the information being transmitted. The rise and fall of the pulse amplitude correspond to the binary values (1 and 0).

3. **Statement 3: The modulation index (μ) is kept greater than or equal to 1 to avoid distortion.**
- **Analysis:** This statement is false. The modulation index can range from 0 to 1 or even exceed 1, but it is not a requirement that it must be greater than or equal to 1 to avoid distortion. In fact, a modulation index greater than 1 can lead to distortion in the signal.

4. **Statement 4: (Assuming a fourth statement is present for completeness)**
- **Analysis:** Since the fourth statement is not provided, we will focus on the first three statements.

### Conclusion:
The incorrect statement among the options given is **Statement 3**: "The modulation index (μ) is kept greater than or equal to 1 to avoid distortion."