Problem in understanding DDFS (Direct Digital Frequency Synthesizer.)

1. How accurate is DDS?
2. What is direct digital frequency synthesizer?
3. What provides the main input to the phase accumulator in a direct digital synthesizer?
4. What is DDS DAC?

How accurate is DDS?

* The ability to generate arbitrary frequencies with accuracy and stability, limited only by the oscillator used to clock the phase accumulator. Crystal oscillators, depending on their specifications, can deliver tolerances of 50 parts per million to ~0.1 part per billion, making DDS extremely accurate.

What is direct digital frequency synthesizer?

Direct digital frequency synthesis (DDFS) is a method of producing an analog waveform—usually a sine wave— by generating a time-varying signal in digital form and then performing a digital-to-analog conversion.

What provides the main input to the phase accumulator in a direct digital synthesizer?

The binary number in the frequency register provides the main input to the phase accumulator. If a sine look-up table is used, the phase accumulator computes a phase (angle) address for the look-up table, which outputs the digital value of amplitude—corresponding to the sine of that phase angle—to the DAC.

What is DDS DAC?

Read more. Complete Direct Digital Synthesis (DDS) is a technique for producing an analog waveform by manipulating a fixed system clock digitally then running the output through a DAC. This allows for fine frequency resolution over a wide range of frequencies and quick switching between those frequencies.