The term channel is used to indicate

Options

A. the amplitude range allocated to a given source
B. the frequency range allocated to a given source
C. the voltage-range allocated to a given source
D. all of the above

Explanation

**Step-by-Step Solution:**

1. **Understanding the Concept of a Channel**: In communication systems, a channel refers to the medium through which information is transmitted from a sender to a receiver. It is essential to understand that multiple signals can be transmitted simultaneously, and to avoid interference between these signals, specific ranges are allocated.

2. **Identifying the Role of Frequency**: The primary way to prevent interference between different signals is by allocating distinct frequency ranges to each transmitter. Each transmitter operates on a specific frequency band, which helps in distinguishing between different signals.

3. **Analyzing the Options Provided**:
- **Option a**: The amplitude range allocated to a given source - This is not correct because amplitude does not define a channel.
- **Option b**: The frequency range allocated to a given source - This is correct, as it describes how channels are defined in communication systems.
- **Option c**: The voltage range allocated to a given source - This is also incorrect, as voltage does not define a channel.
- **Option d**: None of these - This is incorrect since option b is valid.

4. **Conclusion**: Based on the analysis, the correct answer is that the term channel is used to indicate the frequency range allocated to a given source.

**Final Answer**: The term channel is used to indicate **b. The frequency range allocated to a given source**.

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