*Question E8B10:
What is frequency division multiplexing (FDM)?*  

*Correct Answer is  B: Dividing the transmitted signal into separate frequency bands that each carry a different data stream*  

### AI Response: (may contain errors)  

Frequency Division Multiplexing (FDM) is a technique used to transmit multiple signals simultaneously over a single communication channel by dividing the available bandwidth into separate frequency bands. Each band carries a different data stream, allowing for efficient use of the available spectrum.

### Correct Answer Explanation:
- **Correct Answer: B**: "Dividing the transmitted signal into separate frequency bands that each carry a different data stream."
  - In FDM, the total bandwidth is split into smaller frequency bands, each assigned to a different signal. This allows multiple signals to be transmitted at the same time without interference, as each signal occupies a unique frequency range.

### Incorrect Answer Explanations:
- **Choice A**: "The transmitted signal jumps from band to band at a predetermined rate."
  - This describes a technique known as Frequency Hopping Spread Spectrum (FHSS), not FDM. In FHSS, the signal changes frequencies rapidly, while FDM maintains fixed frequency bands for each signal.

- **Choice C**: "The transmitted signal is divided into packets of information."
  - This describes packet switching, which is a method used in digital communications where data is broken into packets for transmission. FDM does not involve packetization; it focuses on frequency allocation.

- **Choice D**: "Two or more information streams are merged into a digital combiner, which then pulse position modulates the transmitter."
  - This describes a different technique involving digital signal processing and modulation, not FDM. FDM specifically deals with the allocation of frequency bands rather than combining streams for modulation.

### Summary:
- FDM is effective for transmitting multiple signals simultaneously by allocating distinct frequency bands.
- It is essential to understand the differences between FDM and other multiplexing techniques like FHSS and packet switching for the exam.

### Key Concept:
- **Bandwidth Allocation**: In FDM, the total bandwidth $B$ is divided into $N$ frequency bands, where each band has a bandwidth of $B/N$. This ensures that each signal can be transmitted without interference.