Question
Which of the following is characteristic of a direct digital synthesizer (DDS)?
Answer Options
- A) Extremely narrow tuning range
- B) Relatively high-power output
- C) Pure sine wave output
- D) Variable output frequency with the stability of a crystal oscillator
Correct Answer: D
Explanation
A Direct Digital Synthesizer (DDS) is a method of generating arbitrary waveforms from a single, fixed-frequency reference clock. Modern transceivers use DDS technology for their Variable Frequency Oscillators (VFOs).
The key characteristic of a DDS is its ability to produce a variable output frequency with the stability of a crystal oscillator. Since the output frequency is mathematically derived from a fixed, highly stable master clock (usually a temperature-compensated crystal oscillator, or TCXO), the output frequency is incredibly accurate and stable, making it ideal for modern radio communication.
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