Reference Input & Output
Windfreak Technologies RF signal generators with reference input and output access can achieve better phase noise or more accurate frequency settings. With Windfreak devices, if the internal reference is used, then that reference frequency is available on the reference I/O connector (if included). The internal reference may also be turned off with the supplied GUI so that an external reference can be applied.
In general, the phase noise in a PLL circuit gets better as the reference or phase comparison frequency is increased. While the TCXO reference inside of Windfreak products is high quality, an OCXO will exhibit much higher accuracy and lower phase noise. Combine this with higher reference frequencies and the phase noise could go down by several dB, especially at offsets of 1KHz or less.
Also, when sharing the same reference with multiple RF signal generators, the frequency among all outputs will have the same accuracy, and, if on the same RF frequencies, have coherent (non-rotating) phases.