Check out the latest feature article added to the site - it covers an FPGA-based design for producing an arbitrary-frequency generator.
Written by Eugene Palatnik, of ITEC Engineering, it is entitled: FPGA-based design yields low-cost arbitrary-frequency generator
Many systems divide a crystal frequency by an integer number to generate clock signals. Unfortunately, the integer divisor limits the available set of output frequencies. Applications such as arbitrary-waveform and -frequency generators and biomedical-signal simulators require low-jitter signals at odd sets of frequencies. For such applications, you can use a phase-accumulator-based frequency generator.
With an output that has a highly predictable frequency resolution and low and predictable jitter, the autor believes it is suited for many applications. Note, though, it is one for mathematicians!
(Note that the FPGA image is just generic - it is taken from another EW article)
FPGA