The purpose of ...A... is to convert the message signal produced by the source of information into a form suitable for transmission through the ...B... Here, A and B refer to

Options

A. channel, transmitter
B. transmitter, channel
C. receiver, transmitter
D. receiver, channel

Explanation

To solve the question regarding the purpose of A and B in the context of communication systems, we can break it down into a step-by-step solution.

### Step-by-Step Solution:

1. **Understanding the Components**:
- In a communication system, there are typically three main components: the transmitter, the channel, and the receiver.
- The transmitter is responsible for sending the signal, the channel is the medium through which the signal travels, and the receiver is the device that receives the signal.

2. **Identifying A and B**:
- The question states that the purpose of A is to convert the message signal produced by the source of information into a form suitable for transmission through B.
- Here, A refers to the component that prepares the signal for transmission, and B refers to the medium through which the signal is transmitted.

3. **Determining the Purpose of A**:
- The purpose of A (the transmitter) is to convert the low-frequency message signal into a high-frequency carrier wave. This conversion is essential because low-frequency signals have low energy and require larger antennas for transmission, which is not practical.
- By using a high-frequency carrier wave, the transmitter increases the energy of the signal, making it suitable for transmission through the channel.

4. **Identifying B**:
- B refers to the channel, which is the medium through which the signal travels. This can include various mediums such as air, optical fibers, or water.
- The channel is crucial because it determines how effectively the signal can be transmitted from the transmitter to the receiver.

5. **Final Identification**:
- Therefore, A is the **Transmitter** and B is the **Channel**.

### Conclusion:
The correct answers are:
- A = Transmitter
- B = Channel