The output frequency fout of the DDS waveform for a single channel configuration is a function of the system clock frequency fclk, the modulus M, and the phase increment value ΔΘ. The output frequency in Hertz is defined by:
For example, if the DDS parameters are:
- fclk = 120 MHz
- M = 1000
- ∆Θ = 12 (decimal)
Then the output frequency is calculated as follows:
- fout= 120 x 106 x 12 / 1000
- fout= 1.44 MHz
The phase increment value ∆Θ required to generate an output frequency fout Hz is:
If the DDS core is time-division multiplexed to do multiple channels, then the effective clock frequency per channel is reduced. For C channels, the phase increment required is:
